Aphids on potatoes? Well, why not? They’re on everything else!
Potatoes are susceptible to two different types of aphids: green peach aphids and potato aphids. Today, we will learn about potato aphids.
Originally from North America, these pests are now found everywhere potatoes are grown. And potatoes are not their only food of choice. Your cabbages, tomatoes, eggplant, and peppers are also at risk, along with many other food crops.
Potato aphid description
Potato aphids (Macrosiphum euphorbiae) can be either green or pink, with a dark dorsal stripe, and they tend to be larger, with longer legs, than most other aphid species. When feeding on tomatoes, potato aphids become distinctly red. They have the same long-legged, soft, pear-shaped wingless body of other aphids. As populations boom, or food becomes otherwise scarce, some aphids will develop wings with which to fly to new feeding grounds.
Potato aphid lifecycle
Potato aphids, like other aphids, are phenomenally prolific. A single female aphid can produce 600 billion descendants in a single season. Aphids reproduce both sexually and asexually. When females produce offspring without male intervention (parthenogenesis), the offspring are born live and significantly smaller than their co-authored siblings. When reproduction involves a male counterpart, offspring are laid as eggs that overwinter in nearby weeds, or on other host plants. Adult aphids molt four times, leaving behind telltale white skins.
Damage caused by potato aphids
Aphid feeding is usually first seen as deformed leaves. As aphids feed, they damage plant tissue and disrupt the balance of growth hormones. This can reduce or eliminate crop size, and it can kill young plants. These sap sucking pests tend to cluster together, piercing plant tissue and sucking out nutrient rich fluids. They also poop out sugary honeydew, which attracts protective, disease-carrying ants, and creates habitat for sooty mold.
Potato aphid feeding can certainly weaken plants, but the real problem is that these aphids carry and transmit a number of viral diseases, such as cucumber mosaic, lettuce mosaic, bearded iris mosaic, narcissus yellow stripe virus, tulip breaking virus, potato virus Y, beet mild yellowing virus, beet yellows virus, alfalfa mosaic, and potato leafroll disease. Plants infected with potato leafroll disease will produce potatoes with a network of browning phloem tissue, called net necrosis, that is very unappetizing. Once a potato plant is infected with leafroll, it and three plants in all directions should be removed to prevent further spread of the disease.
Controlling potato aphids
The battle against aphids in the garden never ends. It starts by monitoring plants regularly for signs of infestation. Potato aphids tend to prefer the lower portions of plants, the undersides of leaves, and around new buds. You can dislodge aphids with a powerful stream of water from the garden hose, but it is practically impossible to get every single aphid off your potato plants in this way, and it only takes one aphid to start the whole process over again. Insecticidal soaps can be used with better results, but you have to make sure you wet every surface of the plant. Personally, I wipe them off whenever I see them. I like to think it slows them down a little, if nothing else.
The next step in controlling potato aphids is to remove nearby plants that might harbor these pests. This means keeping weeds away from potato patch. Malva, penny cress, and various mustards, in particular, can act as early season host plants for this pest.
Luckily, lady beetles, lacewings, syrphid or hoverfly larvae, and parasitic wasps will all help control potato aphid populations. That’s assuming you haven’t used broad spectrum pesticides and wiped out your helpers.
What's eating your potatoes?
From 1845 through 1852, over one million residents of Ireland starved to death, and another two million were forced to emigrate elsewhere, all because of potato blight. Before you lose your crop to potato blight, let’s learn more about this tiny water mold.
In the world of scientific classification, water molds are a type of mostly land dwelling organisms called oomycetes. Oomycetes fall between fungi and algae. These pathogens attack stems, roots, and tubers, and frequently kill host plants. Common water mold diseases include phytophthora tentaculata, crown rot, damping off disease, sudden oak death, and potato blight. Potato blight, also known as late blight, is caused by a specific oomycete called Phytophthora infestans. The word phytophthora means ‘plant killer’, and rightfully so.
The Great Potato Famine
The pathogen responsible for potato blight was first identified in 1843, in New York and Philadelphia. Wind then spread the spores throughout neighboring regions. Since potatoes weren’t found in North America until the 1500s, and then not grown regularly until the 1700s, potato blight wasn’t seen as a serious threat to anyone. Then, when seed potatoes were sent to Belgium in 1845, all hell broke loose for potato farmers across Europe. Ireland was hit the hardest in what became known as the Great Famine, or the Great Starvation. Since monoculture of a single potato species was common practice at the time, it wasn’t difficult for this disease to take hold.
Potato blight lifecycle
The potato blight pathogen prefers cool, moist environments, which Ireland has in abundance. Spores are produced 54°F to 65°F, while lesions develop when temperatures are between 64°F and 75°F. And it takes surprisingly little moisture to create a water mold habitat. Morning dew on a leaf is all it takes, though more water is preferable. These pathogens can also attack other members of the nightshade family, such as tomatoes, though another disease, called early blight (Alternaria solani) is often the culprit on tomatoes.
Water mold reproduction is odd. [Remember, oomycetes fall somewhere between algae and fungi.] Water mold reproduction starts with an asexual phase during which branching structures, called hypha, grow, followed by spore development. Then, the receptacle where spores develop, called sporangia, begin to germinate, much the way pollen granules germinate in fertilization. Then, our tiny water mold grows more hypha, and the process continues. Sexual reproduction occurs when two mating types meet.
Symptoms of potato blight
Potato blight symptoms start out as small, dark green, irregularly shaped, water-soaked spots on leaves, stems, petioles, and tubers. These spots have a yellowish halo. These lesions expand rapidly when moisture is present, turning purplish brown. Grayish white fuzz can also be seen on the underside of leaves as spores develop.
A special group of genetically modified potatoes has been developed with a resistance to potato blight. These cisgenic potatoes appear unable to catch the disease. If you prefer not growing genetically modified plants, there are other ways to prevent potato blight from taking hold.
How to prevent potato blight
Fixed copper sprays are the best preventative measures against potato blight. In fact, during WWII, when copper was being used to make artillery shells, farmers faced new threats from potato blight because they were unable to spray their fields.
Potato blight can find its way into your potato bed through contaminated potatoes, visitors and materials which have come from areas infested with the pathogen, and by rain or irrigation water splashing from contaminated plants to healthy plants. These are excellent reasons for quarantining new plants and avoiding the use of grocery store produce as a plant source. [Just because a plant is healthy enough to eat now does not mean it isn’t carrying diseases that may stay in your soil for years.]
Excess moisture should be avoided in areas susceptible to potato blight. This means allowing the soil to dry out between waterings, pruning for good air flow, and adding organic material to the soil to improve drainage.
A healthy potato bed is a thing of beauty. Let’s keep it that way!
Rain beetles only occur in California, Oregon, and southernmost Washington.
While they live here all year, rain beetles can only be seen after the year’s first big rain, or at spring’s first big snow melt. Even then, you will probably only see the males.
Rain beetle description
Rain beetles are scarabs, making them cousins to rose chafers, hoopla beetles, and Junebugs. Rain beetles (genus Pleocoma) are robust, shiny beetles. They are over one inch long, dark brown to reddish brown, with fuzzy undersides. [The word ‘Pleocoma’ is Greek for ‘abundant hair’.] That hair can range from black and brown to yellow.
Damage caused by rain beetles
Adult rain beetles do not eat. They have no functional mouths or digestive systems, so they do not cause any damage to the garden. Their larvae, however, are another story altogether. Rain beetle larvae feed on the roots of fruit, nut, and ornamental trees and shrubs, and grasses, along with fungi and other organic matter. Rain beetle larvae seem to prefer the roots of apple, pear, and other orchard trees.
Rain beetle behavior
Rain beetle larvae do not dig through the soil, per se. Instead, they move through it by eating it and pooping it out. Burrowing up to 3 inches each day, a rain beetle larva can be found anywhere in the top 8- to 10-feet of soil. Adult rain beetles use powerful legs and a V-shaped scoop found on top of their head to push their way through the soil.
Male rain beetles generally emerge at dusk, though they can be seen flying around in the day, especially if it is raining. Males fly low to the the ground, looking for mates. Male rain beetles are relatively good flyers, though they will bang into your windows at night, being attracted to lights and bodies of water. Flightless females stay in the ground, emitting a pheromone that attracts the males. This pheromone has a lemony scent that is so strong even people can smell it.
Rain beetle lifecycle
Rain beetles are long lived bugs. From egg, to larva, to pupa, to adult can take 12 years. [Most beetle species only live one year.] That being said, by the time you see a rain beetle, it is probably only hours or minutes from death. Male rain beetles only store enough energy as fat from their more youthful stages to fly for a couple of hours, looking for mates, before dying.
After mating, female rain beetles burrow a spiral-shaped tunnel, as much as 10-feet below the soil surface, laying 40 to 50 eggs as she goes. In 2 months, the eggs hatch and the larvae begin feeding.
Rain beetles were once found throughout California and Oregon. Now, they are generally only found in pockets of foothill and mountain habitats. Being flightless and ground dwelling, female rain beetles have been wiped out everywhere urban development has occurred.
Rain beetle controls
Since rain beetles spend nearly all of their lives underground, chemical controls are ineffective. For the most part, rain beetles are more of a nuisance than a significant pest, though you can catch males in a butterfly net, if they really bother you.
Overwatering is the most common cause of death for houseplants and holiday plants. Under-watering can be just as devastating, indoors or out. So, how much water is enough, and how much is too much? And how can you tell?
Moisture meters measure the amount of available water in a soil sample. You can buy a simple moisture meter at any garden supply store. You can also install a multi-million dollar moisture sensing system throughout your landscape, but that’s beyond the scope of this blog (and my budget).
The trick to using a moisture meter is understanding the reading, and using the information properly to avoid water-stress. Before we learn how to read those results, let’s see what types of moisture meters are available.
Types of moisture meters
Handheld moisture meters measure soil moisture using a bimetal tip that measure electric conductivity. Other types of moisture meters use a variety of methods to measure soil moisture and its availability to plant roots. These other tools include gypsum blocks, tensiometers, watermarks, and neutron probes. [A neutron probe is a radioactive tool used by professionals who have been trained and licensed. If you get your hands on one of these, please donate it to your local County Extension Office as soon as possible.] Moisture meters either measure the amount of water in a soil (content), or how tightly the soil holds that water (tension).
The most commonly available handheld moisture meters do not require any real understanding about soil moisture. You simply stick the probe(s) into the soil, look at the display, and water accordingly.
These inexpensive moisture meters are very useful tools, though the probes tend to corrode rather quickly. Since each type of soil has unique properties, it is important to be able to calibrate your moisture meter for your soil texture. Salt levels in soil can have a big impact on moisture meter readings. If your soil has high salt levels, you will need to take that into account, as well. Also, where you place your moisture meter probe has a big impact on the usefulness of the information.
If you want to know more about soil moisture, read on. Otherwise, skip to the bottom section on caring for your moisture meter.
Each soil has its own water holding capacity. For example, if you have sandy soil that is saturated with water, gravity will pull any excess water downward, away from plant roots. If you have clay soil, as we do in the Bay Area, water may be present, but much of it will be unavailable to plant roots. This is because clay has many small spaces with which to hold tightly to water molecules. [Adding organic material to clay soil increases the availability of that water.] The extent to which soil holds onto water is called its soil moisture tension. Soil moisture tension is measured in centibars (cbar). Most plants perform best between 40 and 80 cbar.
The amount of moisture available to plant roots is called a soil’s plant available water. Plant available water (PAW) can be measured as a percentage of weight, a percentage of volume, or by depth, as inches of water per foot of soil.
When plant roots are unable to pull water from a soil, it will have reached its wilting point. The permanent wilting point occurs at 15 to 20% for clay soil, 10 to 15% in loamy soil, and at 5 to 10% in sandy soil.
A plant’s need for water varies throughout its lifecycle. The biggest demand for water occurs during vegetative growth and initial fruit production.
Since this normally occurs during summer, when evaporation is at its peak, maintaining the proper moisture level makes the difference between healthy, productive plants, and plants that are struggling for survival. As temperatures drop or senescence (preparation for death) begins, the need for water drops dramatically. Adding more than is needed creates a different sort of life-threatening set of conditions. [Can you say fungal disease?]
Caring for your moisture meter
The sensor found at the end of most moisture meter probes is sensitive to damage and corrosion. To keep your moisture meter operating properly, be sure to wipe it off after each use and do not force it into dry, compacted soil. If a reading is needed under those conditions, create a starter hole with a screwdriver. Also, watch out for rocks, which can damage the probe.
As an added benefit, many moisture meters can also provide you with soil pH information. This is one tool every gardener should have on hand and use regularly. Just remember, you get what you pay for.
Most fruit and nut trees available today are actually two different plants that have been grafted together. Where those two plants come together is called the graft union, or graft collar.
Graft unions are usually easy to spot. They tend to be lumpy, raised areas. The shape of the graft union depends on the type of graft used to merge the two plants.
People have been cloning plants with grafting for thousands of years, and this method of plant propagation is not limited to trees. Your store-bought tomatoes and other vegetables may also have been grafted.
Grafting is done by inserting a shoot or twig, called the scion, into a slit cut into the trunk or stem of another plant, called the rootstock. This allows the vascular bundles of the two plants to merge, allowing water and nutrients to move between the two.
Grafting allows us to take advantage of one plant variety’s strong root system and another plant’s heavy fruit, nut, or flower production. Grafting allows us to select plants for their combined characteristics of size, hardiness, growth habit, growth rate, disease and pest resistance, and flavor.
The name of the plant you buy usually refers to the aboveground portion of the graft, though you may also see mention of the rootstock. Grafting is what allows you to have a tree that produces multiple varieties of fruit. These graft unions are found higher in the tree canopy.
Bare root trees
Bare root trees commonly start appearing in garden centers in January in the Bay Area. If you shop from knowledgable, reputable growers, the plants they have available will be suited to the local climate. If you are shopping bulk discount stores, well, you may be getting something else entirely. Wherever you get your fruit and nut trees, be sure to inspect the graft union for signs of damage, disease, vine mealybug nymphs, and other insects. Graft unions are delicate, vulnerable areas. Until relatively recently, it was suggested that the graft union be positioned below soil level. We now know that this is a really bad idea, leading to several problems.
Graft union problems
Improper planting depth is currently the primary reason why trees fail. Part of this is due to bacterial and fungal diseases entering the tree through the graft union, causing root rot, crown gall, and phytophthora root and crown rot, among others. These problems can be avoided by ensuring that your plants are installed at the proper depth. This generally means that the graft union will be 2 to 4 inches above the soil level, or more. [The higher the graft union, the smaller the mature tree will become.] If stem growth starts occurring below the graft union, it is called graft union suckering.
Graft union suckering
Graft union suckering occurs when the graft is less than successful. These suckers start growing out of the root stock portion of the stem, which may sound fine for the root system, but it is bad for the overall plant. Very often, rootstock plants are highly susceptible to aboveground pests and diseases, and they rarely produce desirable crops. If graft union suckers appear, remove them as close to the branch collar as possible, without damaging the collar.
Take a closer look at the trees, shrubs, and other plants in your garden. Do you see any graft unions? Are they above the soil line? I hope so!
There is something about garden water features that makes everything better.
Calming, refreshing, or splashing playfully, water has the ability to improve our mood, create art, and support local biodiversity. And, hey, it looks nice!
Benefits of water features
Water features provide many benefits other than the artistic appeal. Water features can provide life-sustaining moisture for hummingbirds, butterflies, other insects, reptiles, and amphibians, many of which are severely threatened these days with habitat loss. You can encourage honey bees and other pollinators to come to your garden when a water feature is present.
Water features can suit any style, from rustic to elegant, quirky to traditional. Water features also tend to improve curb appeal and property values, if you are thinking of selling your home. If you are even the least bit handy, you can install your own garden water feature. [Instructables has some excellent ideas!] You can get the necessary information from your local library, or you can buy a kit.
Types of garden water features
Water features come in all shapes and sizes. They can be birdbaths, fountains, or waterfalls, ponds or pools, or even a creek or stream. Starting with the most simple water feature, and moving through to more complex features, each has its own pros and cons.
A simple birdbath can often be found at yard sales and thrift stores. You can also make your own with a wide, shallow bowl, or any other container that has sloping sides. While a birdbath requires regular refilling and cleaning, it is very rewarding to see goldfinches, mourning doves, and jay birds drinking and bathing. Add a pump to a small water-holding container and you have a fountain, or a waterfall.
Fountains and waterfalls
Fountains and waterfalls are especially good at transforming a space without a huge expense. And you can now find solar pumps to power a garden water fountain. Fountains add water movement and oxygenation to your water feature. This slows the growth of algae and reduces the likelihood of creating a mosquito breeding ground. Also, the sound of falling water can be very soothing, and it can mask less desirable sounds of traffic or noisy neighbors. Moving water also adds moisture to and helps clean the surrounding air, supporting nearby plants and animals, along with your family. You will need to maintain water levels in your fountain, especially in summer. Also, fountains do need to be cleaned occasionally, to keep water flowing through the pump. If you have more room, a pool or pond might make a lovely addition to your garden.
Ponds and pools
While swimming pools have chemicals and steep sides that can prove detrimental to most local wildlife, small ponds and pools take up only a moderate amount of space and can often be self-sustaining. [And who wants the wildlife playing in your swimming pool, anyway?] A small pond can create a shady sanctuary for weary feet, brilliantly colored koi, and overheated dogs, along with local wildlife. You can take a pond idea one step further by using the soil dug out for the pond to create a sloping creek.
Creeks and streams
Backyard creeks and streams create a magical space in your yard. And these systems are mostly self-contained. Water is pumped from the pond, through a filter, and then up over a small waterfall. Because the water is moving, you get the sights and sounds of running water, the water is oxygenated, and the filtering system reduces the amount of maintenance you need to provide.
Ponds with creeks also create ideal habitat for shy amphibians and reptiles who will feed on pesky beetles, wasps, and other pests. You can find affordable kits that walk you through the installation, or you can hire a professional.
Garden water features add beauty and value to your home and garden, while improving the quality of life for all nearby living things.
Lenticels are porous tissues used in plant respiration.
Plant respiration involves exchanging oxygen, carbon dioxide, and water vapor as part of photosynthesis and other cellular functions to generate or release energy.
The words ‘lenticel’ and ‘lenticular’ refer to the more common lentil-shape of these openings, but theses raised areas can be round, oval, or elongated. In some cases, such as silver birch, lenticels appear as horizontal cracks.
There are two types of lenticels: those found in the stems, trunks, and roots of woody plants and trees, and those found in the skin of certain fruits, such as apples.
Many apples and pears, in particular, have fruit skin lenticels. These are the tiny nicks of color seen on the skin. These lenticels start out light colored and then darken as the fruit reaches maturity and is ripe for picking. This darkening occurs because of the formation of cork cells. These openings are often the site of failing stoma, broken off trichomes, or other points of early damage, rather than planned growth. The number of lenticels seen on pome fruits can vary by species and by the availability of water during early development.
Bacterial and fungal disease can enter the fruit through these openings. There is a global skin disorder of pome fruits, called ‘lenticel breakdown’, in which 1-8 mm pits develop at the lenticels just after processing.
Trees and other woody plants have lenticels in their bark (periderm), both above and below ground. These openings facilitate the necessary exchange of oxygen, carbon dioxide, and water vapor. Since different species have uniquely shaped lenticels, knowing the characteristic shape of a tree’s lenticels can help in identification
Trees growing in low oxygen environments, such as mangroves, have lenticels on specialized roots. Grapes, on the other hand, have lenticels on their pedicels, or flower stems. Grape lenticels react to changes in temperature, rather than oxygen levels.
Did you know that potatoes have lenticels?
Now you know.
Not counting gardeners, there are several types of mammals that may turn up in your garden. Some can be helpful, others can be a royal pain.
Mammals are warm-blooded and more or less intelligent. This can make excluding them from certain areas of the garden problematic. In most cases, there are ways to work around pesky mammals in the garden, without losing your mind or getting in trouble with local law enforcement.
Speaking of law enforcement, before you go trapping, shooting, poisoning, or otherwise dispatching wildlife, you need to track down your local laws and obey them. The low level squirrel feud can turn into a legal nightmare if improper methods are used against them. It’s not worth it - regardless of how tempting it may be when they take your last juicy pears for the umpteenth time!
So, let’s see which animals might end up in the garden and how to protect your plants against them.
There are three types of bats found in California: leaf-nosed bats (4 species), vesper bats (19 species), and free-tailed bats (4 species). These bats are primarily insectivores, capturing insect pests, such as moths, wasps, flies, mosquitoes, in flight, or capturing beetles, ants, and other insects off of leaves or from the ground. This makes bats welcome guests in the garden, though they will sometimes eat ripe fruit. [Who can blame them?] You can attract bats to your garden for the evening shift by installing a bat house.
Deer are the bane of gardeners wherever they are found. These animals can leap small buildings in a single bound. Oh, wait, wrong story. But deer can wipe out an orchard, garden, or landscape, between feeding and trampling, in short order. Really high fencing (and I mean 7- or 8-feet high) might block deer. If your garden is on a slope, you will need fencing that is 10- or 11-feet high! Loud, scaring devices and various repellants can also be used to try and block these determined garden pests, but the effectiveness of these methods doesn’t last very long.
In California, we have deer mice, house mice, and meadow mice, also known as voles. Deer mice and house mice are mostly seed eaters that can wipe out a garden crop before it even starts. Voles are herbivores that will eat your bulbs, tubers, artichoke, beets, Brussels sprouts, celery, cauliflower, sweet potatoes, lettuces, tomatoes, turnips, cabbages… well, you get the idea. If that weren’t enough, voles will also chew the bark off your fruit and nut trees.
While poisons do kill mice, those poisoned mice can then be eaten by other wildlife, or your pets, so I urge you to avoid poisons. And those sticky boards, well, those are just cruel. Also, as the animal struggles to escape the glue, they tend to urinate and defecate and those materials then get slung around as the animal continues to struggle. Instead, good old fashioned mouse traps are still your best bet. They are usually an instant death and generally not very messy. Since all mice can carry hantaviruses, be sure to wear non-fabric gloves whenever handling mice, materials mice may have urinated on, or mice droppings. Also, be sure to thoroughly disinfect any areas inhabited by mice.
Moles and shrews
Shrews and moles may look like mice with deformed noses, but they are not rodents. They are more closely related to hedgehogs. There are 13 shrew species and 4 moles species in California, and they spend most of their lives underground, digging burrows and eating. For their size, shrews have voracious appetites, eating 1/2 to 2 times their body weight each day in worms, insects, and other invertebrates. They will also eat seeds, roots, and bulbs, but mice and pocket gophers are usually the culprits in those cases. Trapping is the most effective control measure, though chemical repellants and noisy, scaring devices can provide some protection.
Opossums may look prehistoric, but they can do your garden a good service. While they will sometimes eat fresh fruit and vegetables, opossums much prefer rotting produce, ticks, slugs and snails. In my book, that makes them a beneficial visitor. If an occasional tomato is lost, well, it seems a fair price.
Pocket gophers spend most of their time underground, digging burrows that lead to many of your garden and ornamental plants. We have 5 gopher species in California and they all feed on roots from below. They will also grab a tasty plant and pull it below ground to enjoy in relative safety. In a single night, one pocket gopher can destroy an entire garden row. Gopher traps are your best control measure.
Rabbits, hares, and pikas
Contrary to popular belief, rabbits are not rodents. They are lagomorphs. There, I said it. Now, what are pikas? And what’s the difference between rabbits and hares? Well, rabbits are smaller than hares, and hares, also known as jackrabbits, have longer legs and ears. Also, hares change color with the seasons, while rabbits do not. As for pikas, you probably won’t ever see them because they tend to live at elevations above the tree line, but they are cute. So are rabbits and hares - until they decimate your salad garden or other crops. Keeping rabbits and hares out of the garden is an unending battle. Since they can burrow, fencing alone is not enough. Raised beds with an exclusionary hardware cloth base may be your only real solution if these pests are feeding on your garden.
Raccoons are smart. And when they are not attacking your chickens or eating your pet’s dinner, they are probably busy eating your garden fruits, berries, nuts, corn, or other grain. Raccoons are attracted to compost piles, trash cans, and bird feeders. Raccoons may also try using your house, chimney, or garage as a nesting site. While young raccoons are adorable, these nests mean the presence of urine, feces, and disease-carrying parasites. Also, unlike opossums, raccoons tend to carry several diseases, such as roundworm, distemper, and rabies. Raccoons are best controlled with live traps. As a furbearer, raccoon pelts have value, so you can probably find someone who will be happy to discharge a trapped raccoon. Otherwise, you can discretely relocate your visitor somewhere more appropriate, and less destructive. Just be sure to check on your legal obligations before you get yourself in trouble.
If you live in the Bay Area, you have rats. There are 2 types of rats found in California: Norway, or sewer, rats and roof rats. These pests are filthy, destructive, and difficult to get rid of. Rats carry disease, chew through electrical wires, and can damage your home, along with your garden. Roof rats prefer avocados, berries, citrus, and nuts, while Norway rats prefer meat and grain. Before you protect your garden against these pests, be sure that there are no points of entry to your home. Once your house is secure, then you can start trapping outdoors in earnest.
In California, we have spotted skunks and striped skunks. In either case, it is a good idea to stay at least 10 feet away from the back end of a distressed skunk. [By the way, skunks have terrible eyesight. If you find yourself closer than you would like, be very, very still, or move away very, very slowly. A startled skunk is an unpleasant experience.] Both skunk species will eat pretty much anything: garbage, compost, pet food, worms, fruit, berries, mushrooms, beetles and other insects, lizards, frogs, snakes, and even the occasional bird egg. Since skunks are the most common carrier of rabies in California, along with distemper, canine hepatitis, leptospirosis, and several other diseases, getting them out of your garden (or out from under your porch) is a good idea. This is best done by professionals. Very often, your local Animal Control Office will remove skunks for free. Once a skunk family is removed, it is important to block whatever area, or remove whatever feature, attracted them in the first place. Otherwise, you will just get a new skunk. If you are unfortunate enough to be bit by a skunk, see your doctor right away. Seriously.
There are two types of squirrels in California: tree squirrels and ground squirrels. If I didn’t have dogs, I would probably have nothing to show for all my work in the garden because of squirrels. I was surprised to learn that they will eat oranges, tomatoes, blueberries, pears, and more. Adding insult to injury, squirrels will, like birds, often only take a bite or two before moving on to the next delectable piece of fruit, leaving a trail of potential disease behind them everywhere they go. Hardware cloth and chicken wire are the only reliable barriers to squirrel feeding, though I have had some success with a repellant called Bobbex-R.
Finally, our pets.
We love our pets. There’s no denying that cats and dogs have a very special place in our hearts. That being said, we do not want cat feces next to our lettuces, or dogs digging up rows of beans or tomatoes. As much as your cat may love being outdoors, researchers at UC Davis have demonstrated that your cat is perfectly happy and actually safer kept indoors. Being stealthy predators, cats can decimate local bird, reptile, and amphibian populations, and we need those other creatures more than your cat needs time outside. Dogs can be trained to provide several beneficial services in the garden. My two dogs will chase squirrels, raccoons, rats, mice, opossum, jays, and cabbageworm butterflies out of my garden. Since most of my gardening is now done in raised beds, I don’t have to worry about the dogs running through them.
While we need to learn how to live and let live, there is nothing wrong with protecting what is yours. This is especially true for disease carrying pests. In some cases, it is simply easier to fence in your crops with netting and tree cages. For those mammals in the garden that must be killed, please use the fastest, most painless method.
How do you manage mammals in your garden?
Frogs, toads, newts and salamanders are all amphibians that you might find in your garden. If you are lucky.
Of course, luck has very little to do with creating a healthy environment. It takes fact based knowledge and a little effort. With just a few slight modifications to your garden, you can create a habitat that attracts these beneficial creatures and encourages them to stay. But why would you want to?
Benefits provided by amphibians
Newts (a type of salamander) are one of the few animals that love to eat slugs. For that reason alone, I am happy to create an amphibian-friendly habitat. Most amphibians are insectivores, which means they will reduce the number of snails, beetles, worms, millipedes, and whatever else they can catch and swallow. While still in their aquatic stage, amphibians will also eat mosquito larvae, along with other insect eggs, water snails, and even small fish.
What are amphibians?
Amphibians are cold-blooded, and many of them start out in water before moving to land. In fact, the word ‘amphibian’ comes to us from the Ancient Greek amphibious, which means ‘both kinds of life’. Amphibians evolved from fish approximately 370 million years ago.
Most of us are familiar with the way frog eggs hatch in water and are called tadpoles. Those tadpoles then lose their gills and tails to become adult frogs and toads. Baby salamanders and many other amphibians also start out in water. At this early stage, they are called larvae. Then, they generally go through some sort of metamorphosis to reach their adult size and shape, and to start breathe using lungs. [Did you know that amphibians also breathe through their skin? For some species, skin breathing is their only form of respiration.] Amphibians often have glands in their skin that release toxins, as a defense mechanism. For this reason, it is a good idea to not handle your garden amphibians - they probably wouldn’t like it anyway.
There are approximately 7,000 species and 3 orders of amphibians in the world: frogs and toads (Anura), salamanders (Urodela), and blindworms, or caecilians (Apoda).
Each region has its own native amphibian population. The first step to improving the biodiversity of your garden is to learn which amphibians are native to your area. Here in the Bay Area, we have a wide variety of amphibians, just looking for a home:
Frogs and toads
Salamanders and newts
How to attract amphibians
Most amphibians start out in or near water, so a pond or similar water feature is the best way to attract amphibians to your landscape. The water should be at least 20 inches deep, and provide both sunny and shady areas, with sloping edges. You will also want to incorporate floating, submerged, and plants that grow from the bottom of your pond to above its surface. The ideal ratio of plants to open water is 1:1. Unlike your swimming pool, you will want algae to grow in your pond, as it is an important food source and it generates oxygen for tadpoles and larvae.
If a pond is completely out of the question, you can still maintain a moist area that includes rotting logs and leaf litter. Brush and rock piles, a stone wall, and basking areas will also help lure these beneficial creatures to your landscape.
Incorporating native plants will attract other natives, providing both food and family for your amphibians. Under no circumstances should you release a nonnative amphibian into your garden. This is how ecological disasters often start.
Other ways you can help your local amphibians include allowing your lawn to grow a little taller, to provide safe travel corridors, reduce or eliminate your use of chemical pesticides, fertilizers, and snail pellets, keep your cat indoors, and monitor your dog. Also, be on the lookout for hidden amphibians when using a lawnmower or weedwacker.
Amphibians are very sensitive to toxins in the environment. This is why they are considered an indicator species. If you have amphibians in your garden, then you know you have created a healthy place. Similar to the recent decline in insect populations, amphibians are currently facing a mass extinction.
Recent studies tell us that, before the 1500s, the expected rate of amphibian extinction would be 1 to 11 species lost over a 500-year period. Since the 1500s, 35 to 130 species of amphibian have become extinct. Since 1980, 9 to 122 more amphibian species have become extinct, with an additional 1,896 species in “imminent danger of extinction”. [The numbers are ranges because it is very difficult to prove that a species is finally and irrevocably gone.]
While most mass extinctions span a couple of million years, the current mass extinctions can be measured in centuries and are caused, both directly and indirectly, by us. The current amphibian population crash is attributed to disease, habitat loss, introduced species, pollution, climate change, and pesticide use, though it is not completely understood. Nor do we understand the long term ramifications of this mass extinction.
The food web and network of life here on Earth is very complex. The loss of amphibians is bound to have serious implications for all of us. Please, do your part to make life possible for amphibians in your garden.
Reptiles in the garden? Let’s hope so!
You may see a lizard scurrying for cover under your lettuces, or a snake slithering across your strawberry patch, but what are they doing in your garden? Are they pests or helpers? And what’s the difference between reptiles and amphibians?
Reptiles v. amphibians
Reptiles and amphibians are both cold-blooded. This does not mean that they are insensitive or cruel, it simply means that they cannot keep themselves warm. If you want to attract reptiles and amphibians to your garden, this is helpful information. The difference between reptiles and amphibians is seen in their skin. Reptiles have dry, scaly skin, while amphibians have smooth, moist skin. Also, amphibians start their lives in water, breathing through gills, while reptiles do not. The classification of reptiles and amphibians may surprise you…
Reptile and amphibian classification
Reptiles (Reptilia) include crocodiles, lizards, turtles, and, wait for it - birds! Before you lose your mind, hear me out. The classification system you grew up with, the Linnaean system, was developed in the 1730’s by Carolus Linnaeus. [I was allowed to pick up and read one of Linnaeus’ first edition copies of Systema naturae, sive regna tria naturae systematice proposita per classes, ordines, genera, & species (1735), during my visit to the Missouri Botanical Gardens!] Linnaeus’ work was based solely on physical characteristics, which meant birds and lizards were in two separate clades. [Clades are subdivisions of a class, descendants of a common ancestor.]
In the 1940’s, a biologist named Willi Hennig came up with a different classification system. His system is based on genetic ancestry, and it is called phylogenetics. Using this more accurate method, birds are members of the reptile class.
What are reptiles?
So what makes a reptile a reptile? First, all reptiles are descended from 4-legged, cold-blooded vertebrates. The reptile clan includes lizards, snakes, and turtles. Skinks are a type of lizard. Most reptiles hatch from eggs (oviparous), while some give live birth (viviparous). Reptiles can range in size from the tiny gecko, at just over 1/2 an inch in length, to the giant, 20-foot saltwater crocodile. Reptiles shed their skin as they grow, so you may find signs of a resident lizard, even if it is too shy to let you catch it out in the open.
What do reptiles eat?
Most reptiles are carnivores or insectivores, though there are a few exceptions. This is what makes [most of] them so useful in the garden. Local reptiles will feed on aphids, ants, beetles, flies, wasps, grasshoppers, slugs and snails, smaller reptiles, baby voles, mice, and rats, sowbugs, earwigs, and practically anything else they can grab, including beneficial spiders and worms, and even baby birds
Why attract reptiles to the garden?
Creating habitat for native reptiles in or near your garden is an easy way to limit pest populations without any chemicals or effort on your part. Just be sure that you do not release an invasive pet reptile into your yard - this is how ecological disasters often start. Please don’t do it. In California, native lizards may not be captured or sold, so you can’t buy them. What you can do is create a welcoming habitat. They will find it, sooner or later.
To attract reptiles, use these tips to provide healthy habitat for reptiles and their prey:
Nearly all reptiles found in California are harmless, with the exception of rattlesnakes, Mexican bearded lizards, gila monsters, and a handful of others. Since reptiles are mostly shy, conflicts are rare. Creating habitat for these elusive garden helpers is a great way to cut back on your work load, while increasing biodiversity in your garden.
Did you know that crocodiles are more closely related to birds than they are to lizards?
Now you know.
Pests, predators, and pollinators, whatever role they play in the garden, insects are everywhere. Or, are they?
Most of the world’s insects evolved in tandem with flowering plants (angiosperms). The majority of insects are small, but a few of those early insects were huge by today’s standards. Dragonflies, known as predatory griffinflies, had wingspans of over 2 feet, and cockroaches were the size of house cats. This was due, in part, to higher oxygen levels in the atmosphere. [31-35% oxygen then, 21% today - don’t panic, though, these levels have been fluctuating since Earth was formed.
Changing oxygen levels were not the only reason for some insects getting smaller. Research has demonstrated that the evolution of insect-eating birds, around 50 million years ago, also played a big role in this change. As bird (and bat) predators started feeding on insects, those prey animals had to become more mobile, harder to see, and less delicious to survive.
Today, insects are facing the biggest threat to their existence - us.
Recent studies show an alarming decrease in insect populations around the globe. Today, we will be learning about different types of insects, the benefits they provide, the problems they face, and ways we can help.
Insects are spineless, 6-legged, armor-plated creatures with three-part bodies, compound eyes, and antennae. To put those characteristics in more scientific terms, insects are invertebrate hexapods with a chitinous exoskeleton.
The word ‘insect’ comes to us from the Latin word insectum, which means ‘with a divided body’. An insect’s body consists of the head, thorax, and abdomen. The legs and wings attach to the thorax. Insects have two types of eyes: simple and compound. Simple eyes (ocelli) are a single lens that can see clearly. Most insects have three simple eyes on top of their head. Compound eyes are those bulging eyes we can easily see. Insects’ compound eyes can have dozens, hundreds, or even thousands of lenses, called facets.
Insects represent between 50 and 90% of all living things on Earth, with over one million named species, and an estimated 4 to 10 million unnamed species. Cousin to spiders and crustaceans, insects come in an astounding array of shapes, sizes, and colors.
A bug by any other name
All bugs are insects, but not all insects are bugs. The word ‘bug’ only refers to true bugs (Hemiptera). True bugs all share piercing, sucking mouthparts that may be used on plants or other insects. There are approximately 80,000 different types of true bugs worldwide, along with 12,000 ant species, 20,000 bee species, and 400,000 types of beetles.
Insects are first classified as winged (Pterygota) or wingless (Apterygota), though not all winged insects can fly. Winged insects are further classified by when and where those wings develop. True flies, bees, fleas, ants, beetles, and butterflies and moths go through a complete metamorphosis, with the wings developing inside the insect during a pupal stage. These insects are in the Endopterygota order. Insects whose wings develop outside of the body, as with dragonflies, lice, mantids, and earwigs, it is considered an incomplete metamorphosis and these insects are in the Exopterygota order.
Most insects hatch from eggs. Rigid exoskeletons are shed in a series of molts, as an insect grows. Some baby insects, such as praying mantis, look like miniature adults, while other insects, such as the Monarch butterfly, go through a complete, 4-stage metamorphosis that includes a pupal stage. While other insects have a 3-stage metamorphosis, in which there is no pupal stage, but a series of nymphal stages.
Pests, parasites and pollinators
Insects are profoundly important components of an environment. They aerate the soil, eat pests, pollinate one-third of all crops (by volume), feed local wildlife (and domestic chickens!), and recycle natural materials into forms usable by plants. Insects play a major role in the creation off topsoil. Insects are also eaten as food by 80% of the world’s nations. Insects can also carry disease, destroy crops, and damage buildings.
Initially, chemical insecticides were seen as the first line of defense against unwanted insects. Because many insects are able to develop a tolerance to those dangerous chemicals (and we cannot), other methods of control are being explored. Very often, beneficial insects, such as parasitic wasps, and other natural predators, such as birds, are encouraged or imported into an area to control harmful insects. These integrated pest management methods reduce our reliance on chemicals and increase local biodiversity.
Declining insect populations
We have been so focused on killing insects off that we didn’t notice, at first, when their populations started to decline, or by how much. Hard, verifiable population facts are still difficult to come by, but recent research has shown a 45% decline in invertebrate populations worldwide. Now, that figure includes more than just insects, but the news is alarming. One German entomological society has recorded nearly 80% less insect biomass in their studies. Another German study reported a 75% decrease in the total flying insect biomass over a 27 year study on 63 different sites. Now, biomass does not mean number of insects. It also does not tell us which type of insects. It simply tells us the amount of insects by weight. Also, not all sites were studied every year, so please do not take this study to say that ’75% of all insects disappeared over 27 years’, because that’s not what the study claims. What it does tell us is that this is a very real problem.
Declining insect populations are the result of many different factors:
The food web ties all living things together. As insect populations fall, so do bird, bat, fish, and amphibian populations. European ornithologists (bird experts) point to declining insect populations as a fundamental reason behind 80% less partridges and turtledove, and 50% less nightingales currently found in the French countryside. In the past 30 years, over half of all Europe’s farmland birds have disappeared, and we have to assume that similar results are occurring locally.
Call to arms
Scientists recognize the critical nature of insect population decline, and the lack of verifiable information. To counteract that lack, large-scale monitoring is being called for, using photos, videos, acoustic recordings, traps, genetic fingerprinting, and citizen science. Automated data collection, worldwide, is the only way we can learn where insects are and how their populations are behaving, and you can help, too.
How you can help insects
There are many things you can do to help insects at home:
Did you know that earwig mothers clean, protect, and keep their eggs warm?
Now you know.
Planting trees too deeply has become the Number One reason why trees fail.
Is your tree failing to thrive? Does it seem overly susceptible to fungal diseases and pests? Are leaves smaller, scorched, or otherwise discolored? Has seasonal leaf color change started occurring earlier? Are wilting, early leaf drop, or twig dieback been occurring? Are you seeing more water sprouts and suckers? Have you noticed less new twig development? It may be that your tree is planted at the incorrect depth. Even heavy fruit production can indicate a problem. Confused? Don’t be. Producing fruit is a tree’s way of continuing the species. If the tree is dying, it will put everything it has into ensuring a big crop of potential future generations.
A properly planted tree shows a flare at the base of the trunk. If your tree looks more like a fence post, it is probably planted too deeply. In the world of botany, a tree planted too deeply is said to be planted ‘below grade’. Trees with exposed roots were planted too shallowly and are ‘above grade’.
Knowing how to plant a tree at the proper depth (or how to correct the problem once it occurs) is the best way to keep your trees healthy and productive.
Start your trees better
When you first buy a young tree, it is usually in a container or the roots are balled up in a burlap bag. In both cases, the young tree has 5 to 20% less feeder roots than a similarly sized tree growing in the ground would have. As a result, these young trees dry out more easily and are easily stressed. If that weren’t problem enough, putting that stressed tree in the ground at the wrong depth can kill it, though it may take a few years. The goal of planting is to get your tree in the ground in such a way that new roots can grow quickly and properly.
Proper planting depth
The majority of a tree’s roots are in the top 18 to 24 inches of soil. They spread out horizontally and vertically from the center, well beyond the drip line, in their search for food, water, and air. [The drip line is the outer circumference of the tree canopy, where rain water drips to the ground.] To plant a tree at the proper depth, use these tips:
Ultimately, you want at least two structural roots to be in the top 1 to 3 inches of soil.
Planting too deeply
The roots closest to the surface are are responsible for a large portion of a tree’s respiration. Tree respiration is not the same thing as human breathing. Tree respiration refers to the process by which a tree performs the gas exchange used to generate or release energy. If a tree is planted too far below grade, those surface roots will still grow horizontally and be unable to get at the air they need.
Planting too shallowly
The primary vertical roots of trees planted too shallowly (above grade) will not grow out into the air. They simply dry up and die. This reduces the water and nutrients available to the growing tree. These upper roots may also try growing into the mulch, where there is limited food and water, or they will simply go around in circles, becoming root bound in the planting hole. This is one way that girdling roots occur.
Girdling roots are those lateral roots found just below the surface that have, for one reason or another, started growing in circles around the tree. This is common with trees kept in containers for too long. Another common way girdling roots occur is when the roots are ‘spun’ into the planting hole, rather than spread out horizontally. Make sure that your planting hole is wide enough to allow those important roots to spread out the way they were meant to grow.
Girdling roots can also occur in compacted soil. If the surrounding soil is compacted, young roots simply cannot penetrate, so they go around and around, looking for a path in their search for moisture, minerals, and air. Curbs, large stones, and building foundations can have similar effects. Girdling roots will kill your tree in 5 to 15 years. It won’t matter how well you fertilize or irrigate your tree.
Speaking of irrigation, be sure to avoid standing water around the trunk of your tree. This can lead to crown rot and other fungal diseases. Instead, use soaker hoses or build an irrigation ring at the tree’s drip line.
Are your trees planted properly?
The easiest way to tell if a tree is planted properly is to dig down an inch or two, with your fingers, next to the trunk. You should come across 4 to 11 substantial roots. If all you find are delicate feeder roots, your tree is planted too deeply. If the roots are visible from the surface, it is too shallow.
How to correct planting depth errors
Trees planted too deeply (below grade) should be dug up, the roots inspected, and then replanted at the proper depth. Trees planted above grade need more soil added around the trunk. First rake the area under the tree to loosen the existing soil. Then add a layer of soil to the proper depth, gently sloping away from the trunk.
Proper planting depth is critical to your tree’s health. Trees planted above or below grade will never thrive. Believe me, it is much easier to do it right in the first place.
Juicy, delicious mangos are one of my favorite tropical fruits.
Mango trees have been around for about 50 million years. This means mangos were around for the mass extinction of the Cretaceous Era, through the extreme climate changes and carbon cycling seen at the end of the Paleocene Era, and again today. Hopefully, mangos will continue to thrive.
Native to South Asia, mangos (Mangifera indica) were part of the spice trade of the 15th and 16th centuries. They were brought to the colonies in the 17th century but, because refrigeration was unavailable, those mangos were pickled. Due to poor communication, other pickled foods, such as sweet peppers, were also referred to as mangos. For a time, the word mango was a verb that meant “to pickle”. But I digress.
Types of mangos
You may be surprised to learn that there are over 500 mango cultivars. In commercial mango orchards, these cultivars are often interplanted to improve pollination. The current market leader is the ‘Tommy Atkins’ variety, due to its nice appearance, productivity, disease resistance, and shelf life. Other, less resilient cultivars, such as ‘Alphonso’, are said to provide better eating enjoyment. With so many cultivars to choose from, home growers can afford to be picky. And those mangos you buy in the store? Many of them (like many other fruits) are picked unripe, so they will never attain the rich flavor of a tree ripened mango. These climatic fruits do continue ripping after leaving the parent plant, but their flavor is never quite what it could have been. [Keep in mind, when you buy mangos at the store, each fruit is picked by hand, then washed, polished, and stickered by people working in warehouses.]
The mango tree
Mangos are stone fruits, right along with apricots and cherries. And that large flat seed - it’s a drupe. Like legumes, pineapple, sorghum, and sweet potatoes, mangos have evolved alongside a helpful bacteria (Gluconacetobacter diazotrophicus) that fixes atmospheric nitrogen, making it available to to the plant and its neighbors, until it goes to seed.
Mango trees are big. When I say big, I mean that they can reach heights of over 130 feet. The crown can be 30 feet across and these trees can produce fruit for more than 300 years. [For comparison, the standard, commercially grown nectarine tree is only expected to produce fruit for 15 years.]
Before you let that size scare you off, know that most commercially grown mango trees are pruned to more manageable sizes, and you can, too.
Mango trees have an extensive root system. They produce a taproot that may go down 20 feet and abundant feeder roots that spread out both horizontally and vertically.
Mangos are evergreen trees with large, broad leaves that start out orangish-pink, and then turn dark shiny red before maturing to dark green. Mangos produce small, white, fragrant flowers in clusters, called panicles. These flowers are pollinated by insects, but it is estimated that less than 1% of the flowers produced by a mango tree will every mature to form a fruit. It takes 4 to 5 months to go from flower to harvestable fruit. And you know that red blush on mango fruit? It has nothing to do with ripeness or sweetness. Instead, it is an indicator of how much sun that side of the fruit was exposed to as it grew.
Inside that delicious fruit is a drupe that fights being removed with every fiber of its being. The reason for this is because mangos, along with avocados, lychees, and cocoa seeds cannot tolerate being dried out or too cold. This type of seed is called recalcitrant. Recalcitrant seeds, also known as unorthodox seeds, lose their viability when stored. Other, orthodox seeds, can tolerate varying degrees of cold, dryness, and storage time. [Note, the stories about seeds from King Tut’s tomb germinating are bogus.] If you want to grow a mango tree from a pit, your odds will improve significantly if you start it right away. Most commercially grown mango cultivars and bare root stock are grafted onto sturdy rootstock.
Before you start growing your own mango tree, you may want to find out if you are sensitive to the oils found in mango stems, sap, and leaves. Some people are sensitive, while others can be severely allergic. Also, mango trees are killed by extended exposure to temperatures below 30°F. If your microclimate receives substantial frost, you may need to protect your tree in winter. If you enjoy snowy winters, you may want to try growing a dwarf mango indoors and pollinating it by hand.
Commercially grown mango trees are often girdled by professionals to increase the sugar content of the fruit, but I advise against this practice, as it can kill your mango tree if done incorrectly.
Mango pests and diseases
Sadly, mango trees are susceptible to a wide variety of pests and diseases. This list is so long that I encourage you to skip it (unless you are really into this sort of thing). If you own a mango tree, you should familiarize yourself with each of these conditions and their treatments.
According to Wikipedia, bacterial diseases of mango include bacterial fruit rot, crown gall, and bacterial canker. Fungal diseases of mango include alternaria leaf spot, anthracnose, black banded disease, black mildew, black mold rot, black rot, blossom blight, blue mold, branch canker, branch necrosis, ceratocystis wilt, charcoal fruit rot, charcoal root rot, crown rot, crusty leaf spot, curvularia blight, felt fungus, fruit rot, galls, grey leaf spot, hendersonia rot, leaf blight, leaf spot, macrophoma rot, fusarium dieback, mucor rot, mushroom root rot, phoma blight, phyllosticta leaf spot, pink disease, powdery mildew, rhizopus rot, various root rots and seed rots, scab, sclerotinia rot, shoestring rot, sooty blotch, sooty molds, stem canker, stem end rot, stem gall, stemphylium rot, stigma leaf spot, tip dieback, transit rot, trunk rot, twig blight, verticillium wilt, white sooty blotch, wood rot, and various forms of dieback. Fixed copper sprays are the most common treatment for many of these fungal diseases.
If that weren’t enough, dagger, lance, and sheathed nematodes, vine mealybugs, guava fruit flies, Mexican fruit flies, melon flies, polyphagous shothole borers, and Oriental fruit flies will attack mango trees, as will an algae that causes red rust, along with a parasitic lichen. Copper, zinc, and boron deficiencies can also cause problems, while too much nitrogen combined with not enough calcium can cause a condition known as soft nose. It’s a wonder we get mangos at all!
Mangos, like most other tropical fruits, produce significant amounts of ethylene gas, a ripening agent. If you need to speed ripen an avocado for guacamole, put it in a paper bag with a mango.
Did you know that mangos are related to cashews?
Now you know.
Indoors or out, you can create an attractive salad garden that provides fresh, crisp salads practically year round.
Imagine walking over to a container, raised bed, or garden patch with a pair of scissors and snipping off fresh ingredients for a salad. Much like an herb garden, salad gardens can provide a variety of colors and textures to your landscape, balcony, or home, as well as delicious, fresh ingredients for your meals.
Where can you grow a salad garden?
Balconies, patios, raised beds, windowsills, towers, and containers are all the space you need to create a salad garden. You can also add salad plants in with your other plantings!
You can use a collection of artistic planter pots, or some of those long, narrow planting containers found at yard sales and thrift stores, or you can get really creative, using takeout containers, an old wheelbarrow, or any other food safe container. And that’s really important. Be sure that whatever container you choose is rated for food use - many pallets are sprayed with a cocktail of chemicals, and some ceramic pots are decorated with toxic enamels. Once you’ve made sure your containers are food safe, it’s time to start choosing your plants!
Choosing plants for a salad garden
Start your salad garden plant selection with foods you and your family will eat and enjoy. There’s no sense using up valuable growing space on plants you don’t want. To select the best plants for your salad garden, consider the time of year each plant will be able to grow in your area. Check with your local County Extension Office and read those seed packets. You can also get all the information you need right here, online. If you will be growing outdoors, be sure to check with the USDA Hardiness Zone Map to identify your zone. You will also want to identify which plants are perennial, which are annuals, and which are biennials:
Salad perennials — chives, patience dock, Malabar spinach, nasturtiums, perennial rocket, sorrel [If you have the space, rhubarb and artichokes provide HUGE, ongoing crops each year]
Salad biennials — kale, parsley, Swiss chard
Salad annuals -- arugula, bok choy, cilantro, dill, lettuces, mizuna, radish, spinach
The perennial plants will serve as year-round anchors in your salad garden, the biennials may take 2 or 3 years before going to seed, and annuals will have to be replaced each year. Or, maybe they won’t. We will get to that in a moment.
One tool for helping in the garden design planning process is to get a package of 3x5 index cards and create a card for each type of plant, putting all the relevant growing information on the card. That information would include:
You can spread the cards out on a table and move them around, to create attractive, productive groupings that will play well together. Consider the height and shape of each plant. A deep container that features tall, wispy dill in the center, offset by brilliantly colored Swiss chard, surrounded by a bright green halo of short, mounding lettuces will look lovely and taste good! Keep a lookout for hybrid dwarf varieties of many salad greens that fit better in containers. If you are growing indoors, you may need to add grow lights during winter.
As your salad garden begins to produce edibles, remember to continue planting new annual seeds every 2 to 4 weeks, whenever the growing conditions are appropriate for each plant. This succession planting will keep you in salad greens practically year round. The important thing about planting a salad garden is to keep planting those seeds!
Surprises in the salad garden
Some plants don’t seem to play be the rules of botany. Beets, for example, are classified as biennials. This means they are ‘supposed’ to generate a fleshy root in the first growing season, to store nutrients for the next growing season, during which seeds are produced. [By the way, beet seed-bearing stems are lovely - they look like Japanese art.] My seed-producing beets, however, have been providing me with beet leaves and seeds for over 5 years now! I use the seeds to grow new plants, and the baby beet leaves are delicious in salads.
You can add a tiny touch of art to your salad garden with ceramic bunnies, glass balls, or tiny metal snails. Will these features help your plants grow? No, they won’t. But they might make you smile!
Harvesting your salad garden
Many salad greens can be harvested using a cut-and-come-again method. This mean you remove outer leaves, as you need them, and the plant simply generates new leaves from its center.
If you allow some of your annual and biennial salad garden plants to complete their lifecycle, going to seed, you will end up with a perpetual motion salad garden that continues to generate new edible plants each year.
While most salad greens prefer cooler temperatures, if you plan around your microclimate, you might be able to put together a salad garden that will continue producing throughout most of the year.
What do you put in your salads?
Stumperies are not Gordian Knots of the pop-quiz world. Instead, stumperies are garden features that use large branches and tree trunks as their anchor points.
While visiting the Missouri Botanical Garden, I was delighted to discover an entire section of the gardens dedicated to stumperies. Coming around a curve in the path, I was met with a cool, green peaceful bit of gardening that featured logs, branches, sheets of bark, tree trunks, and skyward bound tree roots, surrounded by wispy ferns, colorful lichens, and fuzzy mosses. The effect was soothing and peaceful - and who doesn’t need more of that these days?
Originally described as a “Victorian horticultural oddity”, stumperies use branches and other large pieces of tree to create habitat for a wide variety of shade-loving plants, growing them more closely together than might otherwise be possible. First created in 1865 England, stumperies often use storm-damaged or diseased trees to create a unique shade gardening space, rather than going to the trouble of disposing of those trees.
Personally, I had an ancient apricot tree whose trunk had been regularly sprayed with a sprinkler for years before we bought the property. Rot had taken over the tree and the root system was pretty much nonexistent. Rather than waiting for it to fall over on somebody, we tipped it over and moved it to a corner of the yard, where it now serves as a new growing space and a good place to sit.
Stumperies are based on what naturally occurs in a forest. As a tree ages, it eventually falls. When it does, it slowly decomposes, absorbing rain water, improving nearby soil structure, and acting as a ‘nurse log’ to plants that have adapted to growing on rotting wood. To design your own stumpery, you must look at each piece of wood and bark as an artistic component. Try different arrangements until you have achieved something you like. Don’t worry, there are no wrong answers. Here are some tips to creating a healthy stumpery:
Plants used in stumperies
The most common plants found in stumperies are mosses, ferns, and lichens. Hostas, hellebores, epimedium, rhododendrons, bleeding hearts, and some bulbs can also thrive in a stumpery.
You can encourage moss growth on logs and stones by smearing them with yogurt [or that carton of soured milk from the back of the fridge]. You can also install shade-loving edibles, such as arugula, basil, blueberries, bok choy, celery, chervil, chives, cilantro, fenugreek, garlic, ginger, kale, lettuces, Malabar and other spinach, mint, mustards, nasturtiums, onion, parsley, potatoes, raspberries, sorrel, tarragon, and tomatillos. The perennials will continue indefinitely, and you can allow some of the annuals to go through their full lifecycle and propagate themselves!
Benefits of stumperies
Stumperies create micro habitats for local flora and fauna, increasing your garden’s biodiversity. Beetles, toads, and lizards often find sanctuary in all the hidden nooks and crannies provided by a stumpery. Of course, slugs and snails and other pests do, as well. But birds enjoy the extra perches and snacks, so it all balances out.
Stumperies can be a good way to put old wood to work in the garden. They can hide eyesores, make use of neglected corners, and create a whimsical woodland that adds some tranquility to your day. If you don’t have stumps readily available, you can always contact local arborists and construction companies. Very often, they will be happy to provide you with all the material you need for free. [That way, they don’t have to pay to dispose of such large items.] Which reminds me: keep in mind that, eventually, the trees and branches that make up your stumpery will disappear and need to be replaced.
After writing this post, I think I will have to create a more formal stumpery with my apricot trunk. I’ll keep you posted.
While it might be fun to imagine tiny worms wearing hardhats and utility belts, there's nothing cute about carpenterworms.
Carpenterworms (Prionoxystus robiniae) are the larval form of a common moth, and they love to burrow into apricot and pear trees. They can also be found in many ornamental trees, such as maple, oak, birch, cottonwood, ash, and willow. Once these pests are inside your trees, they can be difficult to evict.
As you can see, this is a robust caterpillar. They can be 1/2 an inch in diameter and 2 to 3 inches long. They have a dark, brownish head and a yellowish white body that is covered with fine hairs. They have sharp, hooked legs on the middle section (thorax) and distinct fleshy legs on the abdomen
Damage caused by carpenterworms
These wood-boring insects live in galleries, feeding on sapwood. Knowing the signs of infestation can help you get a handle on this pest before the damage becomes irreversible. The galleries created by carpenterworm feeding tend to be vertical, except for the entrance. These entrances are often found in branch crotches and in bark crevices. Tunnels are 1/2 an inch in diameter and 6 to 10 inches long. This tunneling creates points of entry for many other pests and diseases. Adult female carpenterworms seem to prefer areas that are already infested for egg laying, which can result in multiple galleries in the same area of the same tree. All that feeding and tunneling can weaken branches, making them more likely to break in strong winds, or when supporting heavy crops. Branches can also become girdled by carpenterworm feeding and tunneling, and die.
Adult carpenterworms are large, mottled grey moths that can have a 3-inch wingspan. Their coloration blends with tree bark and lichen. This camouflage makes them difficult to see. If you are able to catch one and spread out its wings, you wing be able to see if you have a male, with orange hind wings, or a female, with off-white hind wings.
Because adult female carpenter moths cannot fly very far, they tend to lay their eggs near the gallery where they were feeding. Three to six eggs are laid in the crevices near an existing gallery entrance. Upon hatching, the larvae immediate start boring into the sapwood, leaving small, rectangular entrance holes.
As they feed, the larvae will occasionally push sawdust and frass (bug poop) out of the ever-widening entry. The larvae will feed on the sapwood and hardwood until they reach maturity, molting 8 to 31 times over the next 2 to 4 years. Finally, mature pupae wriggle their pudgy selves to the entry hole and create a protective pupal case, which will block the hole until adult moths emerge. In California, this usually occurs May through July. As soon as adults start flying, they mate and the cycle continues.
Signs of carpenterworm infestation
The first sign of carpenterworm infestation is stained areas on the trunk. These stains are a combination of sap, sawdust, and frass. You may also see pupal cases sticking 2/3rds of the way out of the tree. Since the stained areas and branch dieback may also be caused by clearwing moths/currant borers, flatheaded borers, bark beetles, and longhorned borers, it is important to identify the pest before trying to control the problem.
Healthy trees are better able to protect themselves, so start by planting trees in the right location, at the proper depth, with regular fertilization and irrigation.
Because these caterpillars are already protected by the tree, insecticides do not work. There are a couple of specific nematodes, Steinernema feltiae or S. carpocapsae, that have been very successful at controlling carpenterworm larvae. Before you place your order, however, make sure that these are exactly the type of beneficial nematodes you are buying. Any other variety will be ineffective against carpenterworms. And be sure to follow the package directions exactly, or you will have wasted your money.
Small infestations can sometimes be controlled by poking long, sharp, flexible wires into the galleries and skewering the caterpillars. This is tricky because you really can’t see if you killed them or not. The only way to really know is to clear all the frass and other debris away from the area and mark the spot with some paint. Then, check the area every week for signs of frass. If frass and sawdust are seen, you missed and the caterpillar is still alive and busy feeding and burrowing.
Heavy infestations are dangerous and should be left to a professional arborist. This is because tree branches that are compromised this badly are very likely to fall on you. Since none of us are exempt from the laws of physics, and heavy branches can paralyze or kill you, stay away from them, and call an expert.
This winter, take a few minutes each week to inspect your trees for signs of frass and sawdust, or pupal cases, and cut those cute little, hardhat wearing pests off at the knees.
Glass snails, such as this whimsical piece by GlassBorisov, are a delightful way to add art and color to houseplants and your garden.
The same is generally not true of real snails. Yesterday morning, after our first rain of the year, I noticed a snail trail. Snail trails are pretty normal in most gardens, but this one ended with a flat-bodied snail I’d never seen before.
Introducing, the glass-snail family (Oxychilidae). Glass-snails get their name because their shells are translucent. Looking closely at my discovery, I could see the snail body through the shell!
Glass-snails are land snails that breathe air. Unlike marine snails, which breath using a single gill, land snails have evolved a single, simple lung. Most glass-snails are omnivores. They eat everything: live plants, dead plants, dead animals, insects, poop, other slugs and snails (and their eggs), sowbugs, and earthworms.
Sorting out glass snails
Specific characteristics are used when comparing different snail species, including height, width, number of whorls, and the umbilicus. The umbilicus is the snail’s bellybutton. It is the tiny opening at the center of the whorls on the underside of the snail’s shell.
Only three glass snails are found in California, at this time: cellar snails, garlic snails, and Drapernaud’s snail. [I'm not sure if my guest is a cellar or Drapernaud's glass-snail, but I'll keep you posted.]
Cellar glass-snails (Oxychilus cellarius) have shiny, translucent yellowish-brown shells are just under 1/2 an inch wide, 1/6 of an inch tall, with 5-1/2 to 6 whorls. The umbilicus is very narrow. The snail itself is bluish-grey, with small brown freckles and a groove that runs along each side of the foot
The garlic glass-snail (Oxychilus alliarius) gets its Latin name, a twist on the onion family (Allium), because they emit a garlic odor when disturbed. Originally from the Netherlands, Great Britain, Ireland, Poland, and the Czech Republic, the garlic snail has spread its range to include Columbia, Latvia, and California. Garlic snails are reddish or greenish brown, and the snail is blackish blue. The shell is 1/4 of an inch in diameter, a little more than 1/8 of an inch high, with 4 or 4-1/2 slightly convex whorls. The umbilicus is 1/6 of the overall diameter, and the whorls are coiled more narrowly than cellar glass-snails.
Drapernaud’s glass-snail (Oxychilus draparnaudi) is larger than the other glass snails, being slightly more than 1/2 an inch in diameter, and the shell is a waxy yellowish-brown on top and somewhat lighter underneath. The body is a dark blue and grey color. Drapernaud’s glass-snail is carnivorous.
How to control snails
Unless you are enjoying artistic versions of this common pest, managing snails is an ongoing task. It comes as no surprise that these snails’ peak breeding season in the Bay Area is autumn, just before our rainy season begins.
The first step in snail management is to inspect and quarantine new plants. A single snail can lay over 400 eggs. Putting new plants into isolation for a couple of days, with a beer trap nearby, can prevent years of frustration. Once infestation occurs, try to reduce hiding places, such as boards, stones, and other debris. Regularly applying slug and snail bait, and using beer traps, can take a big bite out of the snail population, before they start taking bites out of your plants. Going outside with a flashlight at night, you can catch them feeding - handpick them and feed them to your chickens or dispose of them in the trash.
Did you know that snails have a powerful sense of smell?
Now you know.
Growing up in Southern California, I was lucky enough to attend a childcare program that was built on the grounds of a former walnut grove. Scattered throughout the property, there were dozens of ancient walnut trees, great for climbing, tire swings, and more delicious walnuts than any of us kids could possibly have eaten. But we sure tried!
People have been growing walnut trees longer than any other food tree. Nearly 10,000 years ago, in ancient Persia, walnuts were grown for members of the royal family. Traded along the Silk Road, and then via sea trade, Persian walnuts made their way to Rome, where they were called Jupiter’s royal acorn, and to England, where the name was changed to English walnuts, even though they were not being grown commercially in England at that time. In the 1700s, missionaries brought walnuts to California.
Types of walnut trees
There are actually several different trees that qualify as walnut. They are all members of the Juglans genus. The familiar English walnut is only one of four types of walnut tree:
The walnut tree
Walnut is a deciduous hardwood. It is also one of the few trees with a true taproot. [Most tree roots are fibrous.] Walnut trees can take 5 or 6 years before they produce fruit. When selecting a site for a walnut tree, keep in mind that a mature walnut tree can reach 40 to 80 feet, in both height and width, and it can live 50 to 250 years!
Walnut trees, like avocado trees, are monoecious, which means they produce both male and female flowers. Male walnut flowers are catkins that look like hanging cat tails. The female flowers are spiky and short.
Fruits of the walnut tree
Unlike chestnuts, which are both botanical and culinary nuts, the common walnut isn’t a nut at all. You may be surprised to learn that walnuts are actually a type of stone fruit. [I know! I was surprised, too!] This means that the walnuts you enjoy eating are a form of fleshy fruit, known as a drupe. Almonds are also drupes. Surrounded by a thick, green rind, the walnuts you see in the grocery store are not what they look like when they are still hanging in the tree. That rind is actually the fruit of a walnut tree, but you wouldn’t want to eat it. It’s nasty.
Walnut trees, like citrus and many other fruit and nut trees, tend to produce heavy crops one year and a light crop the following year. Known as alternate bearing, these fluctuations allow trees to recover from heavy production years.
You have probably heard that walnut trees put out toxins that make it impossible to grow other plants nearby. This is only partly true. Many plants use a type of chemical warfare, called allelopathy, to reduce competition. Walnut trees produce do produce toxins that can cause some other plants to wilt. Tomatoes, potatoes, eggplant, peppers, blackberries, raspberries, blueberries, and asparagus do not grow well when planted near a black walnut tree, according to the University of Illinois Extension. At the same time, according to the PennState Extension, onions, beets, squash, melons, carrots, parsnips, beans, yarrow, stonecrops, and corn can all be grown near a walnut tree without any problems. In fact, in commercial walnut groves, a type of agroforestry, called alley cropping, is used to plant other crops, such as corn, between the rows of walnut trees.
Propagating walnut trees
While you can certainly buy a bare root walnut tree, there are other ways. You can plant a raw walnut in the ground, or, if you know of someone with a walnut tree, you can use air layering. Layering is a form of vegetative propagation. Strawberry runners are an example of layering. The nice thing about air layering is that the parent plant continues to feed and care for the newly developing plant, since they are still attached to one another. To air layer a walnut, pull a stem down until it touches the ground at what would have been a leaf node. Instead of developing into a leaf, that bud will start putting out roots.
Walnut trees can produce nuts on the same spurs for several years. Because of this, mature walnut trees do not require renewal pruning. The only pruning needed is occasionally thinning branches to maintain overall shape and good health. Young walnut trees are trained using the modified central leader system. In this method, a single, strong shoot is encouraged up the central line of the tree. Two or three lateral branches, spread evenly around the tree, both vertically and horizontally, are allowed to grow. All other branches are removed. Eventually, there can be five to seven lateral branches in place before the central leader is removed.
Walnut pests and diseases
Walnuts are susceptible to an astounding number of pests and diseases. Luckily, walnuts are rugged trees that rarely need assistance in fighting off these foes. It’s still a good idea to know what your tree might be up against. Many varieties of scale insects, including walnut scale, frosted scale, European fruit lecanium scale, San Jose scale, Kuno scale, and Italian pear scale may be found on walnut. Walnut husk flies, aphids, southern fire ants, walnut twig beetles, fall webworms, Pacific flathead borers, navel orangeworms, false chinch bugs, redhumped caterpillars, American plum borers, and Mediterranean fruit flies prefer walnut, as do tortricid moths, such as the light brown apple moth, which can cause leaf roll of walnut. A type of eriophyid mite, called the blister mite, will also attack walnut trees, as will European red mites and webspinning spider mites. Codling moth larvae will burrow into the nut meat of English walnuts, starting in April. You can monitor your trees for many of these pests by using pheromone traps.
Diseases, such as crown gall and walnut blight can be prevented and treated with Bordeaux mixture or fixed copper. Walnut trees may also become infected with anthracnose, armillaria root rot, phytophthora root and crown rot, branch wilt, and several canker diseases. If that weren’t trouble enough, squirrels, voles, pocket gophers, rats, and deer will try to get at as much of your walnut crop as they can.
While many trees are treated with horticultural oils during dormancy, oils should not be used on walnut. Dormant oils are phytotoxic (poisonous) to walnut trees. Like apricot trees, walnut trees are also susceptible to Eutypa dieback. This fungal disease can kill a tree. The easiest way to avoid it is to only prune your walnut tree during summer, when there are no rains expected. Also, make sure that your sprinklers are not hitting the tree’s trunk.
Walnuts contain high levels of oils that can turn rancid. To keep walnut meats fresh, they are left in their shells and placed in cold storage. If you buy walnuts from a store and plan on using them within one month, store them in your refrigerator. Since walnuts can absorb odors, be sure to keep them away from fragrant foods, such as cabbage, broccoli, and fish. Longer storage should be done in the freezer.
Walnut trees can make a magnificent addition to your foodscape, providing decades of delicious nuts and welcoming shade from the summer sun.
Hugelkultur is a no-dig gardening method that uses mounds of logs and branches covered with soil to create growing space. Mounds are commonly used when growing pumpkins, melons, and other cucurbits. These “hills” help prevent waterlogged roots, prone to rot. Hugelkultur is something entirely different.
What is hugelkultur?
Hugelkultur was started in Germany as a way to put woody debris to good use when, at the time, it was illegal to burn it. While proponents state that hugelkultur started “hundreds of years ago”, there is no proof to substantiate that claim. The term was first used in 1962 by Herrman Andrä, a German gardener, when he noted the diversity of plants growing on a pile of woody debris at his grandmother’s home. Andrä and others standardized the method, claiming that the rounded mounds increased growing area and nutrient availability, while storing moisture for growing plants.
How to build a hugelkultur bed
At first, hugelkultur was nothing more than long piles of logs, branches, twigs, and plant waste, such as straw, compost, or sod, covered with soil. In some cases, the design evolved to start with a dug trench or sunken area. The soil removed to make the trench is then used on top of the mound, before planting occurs. The trench method is more commonly used in sandy soils [In another method I found, cardboard, kitchen waste, and old clothing are also incorporated into the mound. Depending on the type of fabric, cotton and wool, as opposed to polyester and rayon, this may or may not be a good idea, respectively.]
These mounds start out 3 feet high and wide. As decomposition occurs, the mounds collapse. After being built, mounds are normally left to rest for several months, though some people plant them right away. Since more decomposition is occurring during the first seasons of a hugelkultur’s life, heavy feeding crops, such as melons, squashes, cabbages, potatoes, and tomatoes are grown first, followed by less demanding crops, such as beans, strawberries, and peas, in later seasons. The average lifespan of a hugelkultur is 5 to 6 years.
Hugelkultur beds are generally positioned so is to be perpendicular to prevailing winds and slopes. For a more whimsical appearance, you can create hugelkultur in whatever shape suits your fancy, such as spirals or mazes. While enthusiasts claim hugelkultur can be used to redirect stormwater, these mounds do not have the strength or stability required of solid earthworks. Instead of protecting against flooding, hugelkulturs can cause even more destruction as floating logs and branches join the water flow.
Problems with hugelkultur
Before you get caught up in the hugelkultur fad, understand that there is, as far as I know, no scientific research to verify the claims made by hugelkultur fans. This doesn't mean the claims are false. It simply means that scientific studies have not yet verified the claims. There are some obvious problems, however.
Traditionally, hugelkulturs were recommended for counteracting “poisoned layers” of soil. This is a terrible idea. Plant roots will move through the mound and into the soil below. Using raised beds with soil barriers, or container gardening, are much better solutions.
Hugelkultur is also said to feed and water nearby plants. In nature, fallen logs do provide water and nutrients to nearby plants. This occurs because they are on top of the soil. As they decompose, they become more porous, storing water and releasing nutrients. These ‘nursery logs’ have long been a source of water and nutrition for young trees and other plants. Hugelkultur logs are underground and do not function in the same way.
Other concerns about hugelkultur include the potential for nutrient deficiencies or toxicities. With all that decomposition going on, nitrogen deficiencies may occur. This can happen because the microorganisms responsible for breaking down plant materials use nitrogen as an energy source. (See nitrogen cycle) On the flip side, so much organic material is being used and broken down that nutrient levels can become excessive, creating toxicities within the soil and groundwater.
Also, the materials used to create the mounds can cause problems of their own. Cedar and walnut contain chemicals that slow the growth of other plants. Some branches, such as Chinese privet, will generate roots all along the buried branches and twigs, and take over the area. Because there is sod, water, soil, and nutrients available in a hugelkultur, weeds can also become a serious problem.
If hugelkultur works for you, wonderful! If you haven’t tried it yet, you may want to put all those logs, stumps, or tree trunks to work in the garden in other ways. Larger pieces make attractive stumperies, while logs make excellent path markers. Ultimately, these woody limbs will break down, adding nutrients and improving soil structure but, as nature intended, these things take time.
Mealybugs have been around for a long time. There is a relatively new, invasive mealybug that may be attacking your grapes.
Traditionally, California grape growers have had to watch for grape mealybugs, obscure mealybugs, and long-tailed mealybugs. These species generally do not cause significant problems, as long as their populations do not get out of hand. They are easy to recognize because of the clusters of grey, soft-bodied females gathering on the underside of leaves and in nooks and crannies. The invasive vine mealybug is another problem altogether.
Vine mealybugs (Planococcus ficus) are native to the Mediterranean areas of North and South Africa and Europe. Vine mealybugs were first seen in California in the mid-1990s and had spread to 17 California counties by 2011. Vine mealybugs are now considered a significant pest of grapes, figs, avocado, apple, bananas, mango, citrus, date palm, and several ornamental plants.
Vine mealybugs are difficult to see because they spend most of their lives protected under the bark, on roots, and around developing buds. Only during spring, when they become active again, can you sometimes see them moving away from the roots and trunk and into the leaf canopy. By summer, vine mealybugs may be found under the bark of first- and second-year canes, among fruit clusters, and under leaves. Sometimes, ants can be seen providing the mealybugs with transportation to their summer feeding grounds.
Vine mealybug description
Vine mealybug females are 1/8 of an inch long, pink, oval-shaped, and covered with a white, mealy wax that also covers filaments (spines) along the sides and posterior end. These filaments are shorter than those seen on other mealybugs, and there are no long tail filaments. Like their cousins, vine mealybugs have a segmented body. Males are tiny, winged, and you’ll probably never see them, unless you have a 30x microscope. They are 0.7 inches long, amber colored, with beaded antennae, one pair of wings, and 4 tail filaments that may stick together. It is important to know which mealybugs you are dealing with. If you see mealybugs, try to collect some and place them in a sealed plastic bag, or in a container of alcohol, and take them to your local County Extension Office for identification. This also helps authorities better understand the spread of this invasive pest.
Vine mealybug lifecycle
In summer, females lay 300 to 700 eggs in the leaves above the fruit in little pouches, called ovisacs. First instar nymphs, called crawlers, are orange and very tiny. During winter, only nymphs are present. They can be found hiding under the bark around the graft union, below the base of spurs, and around pruning wounds. There can be 3 to 7 generations a year.
Damage caused by vine mealybugs
Vine mealybugs are phloem sap suckers that produce significantly more honeydew than native mealybugs. This honeydew attracts protective, disease-carrying ants and creates a growth medium for sooty mold on fruit clusters. These invasive pests can also carry grapevine leafroll viruses and corky bark disease. Vine mealybugs reproduce at a much faster rate than their native cousins.
How to control vine mealybugs
Being an invasive pest, vine mealybugs do not have as a many natural predators as their native cousins. Because vine mealybugs are such a serious threat to California grape growers, parasites of these particular mealybugs have been released in the state. This has helped somewhat, but eradication appears to be impossible at this point. Since these beneficial insects are unavailable to the home grower, the best things you can do to protect your vines is to inspect them regularly, especially during spring, monitor and control ant traffic with sticky barriers, and to quarantine new vines and other plants before installing them. Also, sanitize your tools regularly. Vine mealybugs also feed on burclover, malva, black nightshade, sowthistle and lambsquarters, so controlling these weeds can also help prevent infestation.
Protecting your grapevine from vine mealybugs is an important step toward providing your family with fresh, delicious, organic, homegrown grapes.
You can grow a surprising amount of food in your own yard. Ask me how!