If you live in the Bay Area, growing lemons is a no-brainer. Lemons love this area.
Native to Asia (we think), lemons evolved out of a cross between bitter orange and citron during the times of Ancient Rome. Lemons did not become popular until they were introduced to Persia and Egypt around 700 AD. Christopher Columbus brought lemon seeds to Hispaniola (modern day Haiti and Dominican Republic), but lemon trees were seen as medicinal and ornamental plants at that time. Though they didn’t know about Vitamin C at the time, James Lind discovered that adding lemon juice to the diet prevented scurvy in 1747.
Lemons are a type of fruit called hesperidium. Hesperidium are berries with a leathery skin and fruit that forms in sections, called carpels. Within each carpel are hundreds of juice-filled sacs, called vesicles. Lemons contain citric acid, which is what makes them taste sour. Lemons are only a little more sour than limes, but they can be almost twice as sour as grapefruits, with five times the bite found in orange juice.
The lemon tree
Lemon trees (Citrus limon) are evergreen, which means the leaves stay green all year. They do not, however, handle cold temperatures very well. Mature trees can handle occasional light frosts, but young trees need protection in temperatures below 45°F. Lemon leaves and fruit both have waxy coatings that reduce moisture loss. You can grow a lemon tree in a sunny spot in your yard, in a container, or even on a balcony. The blossoms smell heavenly!
Most grocery store lemons are ‘Eureka’ lemons. This variety is also known as ‘Four Seasons’ because of its continuous production. This is also the most commonly available variety as bare root stock. There is also a pink-skinned variety of ‘Eureka’ that features green and yellow variegated skin. Thinner skinned and seedless “Bonnie Brae’ is grown in San Diego County, CA. If you want to make your own limoncello (lemon liquor), you will want to plant a ‘ ‘Femminello St. Teresa’, also known as ‘Sorrento’ lemons.
Contrary to popular opinion, ‘Meyer’ lemons are actually a cross between citron and a mandarin/pomelo hybrid. Other lemons-that-are-not-lemons include:
Caring for a lemon tree
Lemon trees are relatively trouble free, when grown in an appropriate location. Lemon pruning is normally limited to the standards of removing dead, diseased, and crossing branches. You will also want to remove vertical water shoots. Lemon tree trunks and the upper surface of exposed branches benefit from whitewashing, to prevent sun scald. Regular feeding will help your lemon tree stay healthy and productive. Each of the doasges listed below should be divided into 2 or 3 separate feedings:
1st year - 3 tablespoons of nitrogen per tree
2nd year - 1/4 pound of nitrogen per tree
3rd year - 1/2 pound nitrogen per tree
4th year - 3/4 pound nitrogen per tree
5th year and on - 1 pound nitrogen per tree
Understand that 1/4 pound of nitrogen is not the same thing as 1/4 pound of packaged fertilizer. Assume, for example, that your 5 pound bag of fertilizer has an NPK of 10-5-2. This means that out of the 5 pounds, 10% of the bag is nitrogen, 5% is phosphorus, and 2% is potassium. [The rest is filler.] This works out to 1/2 a pound of nitrogen, a 1/4 pound of phosphorus, and 1/10 of a pound of potassium. In all likelihood, your lemon tree will not need those other nutrients, so they are best left out of the equation (especially until after you get a soil test). An easier way to feed your lemon and other citrus trees is to use blood meal or ammonium sulfate.
Blood meal contains 13.25% nitrogen, 1% phosphorus, and 0.6% potassium. To equal one pound of nitrogen, you would need to apply 7-1/2 pounds of blood meal. Five pounds of ammonium sulfate will give you the same amount of nitrogen. Just remember that these feedings are totals for the year and that they should be spread out over three different feedings, ideally in April, June, and August. Lemon trees also benefit from a top dressing of aged compost.
Lemon pests and diseases
The biggest insect threat to your lemon tree (and lemon trees across the country) is the Asian citrus psyllid, which can infect your tree with a fatal disease called huanglongbing, or HLB, for short. Leaf miners will burrow tunnels in citrus leaves, but the damage is mostly cosmetic, unless it becomes extensive. Other lemon pests include aphids, katydids, citrus cutworms, several varieties of mites, mealybugs, glassy-winged sharpshooters, Fuller rose beetles, hoopla beetles, leafrollers, snails, thrips, whiteflies, and nematodes. Several varieties of scale insects are attracted to lemon trees, including, black scale, brown soft scale, California red scale, citricola scale, cottony cushion scale, and purple scale. Lemon tree diseases include alternaria rot, armillaria root rot, anthracnose, brown rot, citrus blast, exocortis, phytophthora-related diseases, and the Tristeza disease complex.
Like other citrus trees, many lemon trees will follow an abundant year with a year of reduced production. This does not mean that anything is wrong.
Lemons are very easy to grow and they can produce an astounding amount of fruit. Get yours today!
Melon flies could end up costing California farmers over $4.5 billion if they ever get a toe-hold in the state.
Melon flies (Bactrocera cucurbitae) are a type of fruit fly. Native to India and Asia, melon flies were first seen in Hawaii in the late 1800’s. They have now become a devastating pest on the Islands. Quarantine stations have worked long and hard to prevent this pest from entering the Continental U.S. The melon fly was first seen in California in 1956, and several other times since, but whenever melon flies are identified stateside, eradication programs immediately go into affect. These programs use pheromones to attract male melon flies. These males are then sterilized and released. This messes up melon fly breeding. So far, this method has been effective. So, why would a gardener care, if the pest isn’t even here? Because maybe it is.
Melon fly host plants
It would probably be easier to list the plants that are not seen as food by melon flies, but it is important to know where to look, and to know what to watch for, so here’s the fruit fly menu of favorites from your garden:
Melon fly description
The size of a house fly, melon flies are mostly orange or yellow and brown with a pale black T-shape on the abdomen and distinct wing patterns. Wings are clear with a large brown spot at the tip and a brown stripe along the back edge and along the base. Melon fly antennae also have an especially long third segment. Melon fly larvae (maggots) are creamy white, without legs, somewhat flattened at the back end. Maggots are less than 1/2 an inch long. Pupae are somewhat smaller than the maggots, held in a protective case that can be dull white or red, or brownish yellow. Eggs are very tiny, white, and somewhat elliptical.
Melon fly lifecycle
A single female melon fly can lay 1,000 eggs. Eggs are laid on young fruit and tender new stems, which will provide food for newly hatched maggots. Eggs that have been laid under the skin of fruits, or in host plant stems, flowers, and exposed roots, will hatch and the feeding damage begins. There are three larval stages, or instars. After feeding continuously, mature maggots drop to the ground, where they burrow into the top inch of soil and enter a pupal stage. There can be 8 to 10 generations a year.
Melon fly damage
During the heat of the day, adult melon flies rest on the shady undersides of leaves. When temperatures are more comfortable, they feed on nectar, decaying fruit, sap, and bird poop. [Keep in mind, as these pests fly from one food source to another, they can be carrying pathogens from the bird poop to your fruit crop.] Tunneling and feeding create points of entry that allow bacterial, fungal, and viral diseases to enter. Generally, the fruit ends up rotten and inedible.
Melon fly control
Unfortunately, there are not any effective controls available to the home gardener. You can certainly rake up the soil under and around potential host plants, to spot, remove, and report any pupal cases you find, and be sure to quarantine new plants. Currently available insecticides have not been found to work against melon flies.
If you think you see a melon fly, please make every effort to capture or kill it. Then call the CA Pest Hotline at 1-800-491-1899, or your local Department of Agriculture, to report it. Only by working together can we protect commercial agriculture and our own gardens from the melon fruit fly. And don’t smuggle fresh fruit or produce across state lines. There’s a lot more at stake than you might think.
Lovage tastes like a cross between parsley and celery, but it can grow to over 8 feet tall!
Lovage is a perennial herbaceous plant that requires very little care. Stronger tasting than either celery or parsley, a little goes a long way, but all parts of the lovage plant make an excellent addition to soups, salads, casseroles, and stews, and the minced leaves take pasta and potatoes to new heights. Lovage seeds and stems are also used in candy-making.
The lovage plant
Even though lovage looks and smells more like celery, it is actually a member of the carrot, or umbellifer family. While lovage plants can grow more than 8 feet tall, more often, they grow 3 to 6 feet tall and 2 or 3 feet wide. Small yellow flowers grow in umbrella-shaped umbels. Seeds are one-half an inch long. Lovage is native to eastern Europe
How to grow lovage
You can start lovage seeds indoors, 4 to 6 weeks before the last frost date, or outside any time the soil has warmed to at least 60°F. Plant seeds 1/4 inch deep and keep the soil moist until seedlings are several inches tall.
Lovage grows best in full sun to partial shade and it needs soil with plenty of organic matter. You can help your lovage plant thrive by top dressing the planting area ahead of time with aged compost. As the growing season nears the end, you can allow flowers to produce seeds for future crops. In cold regions, the root is dug up and stored where it will be protected from freezing until the next spring.
Lovage has very few pest or disease problems. Leaf miners can cause cosmetic damage, but that’s about it. Because of its rugged demeanor and its celery-like flavor, lovage is an excellent addition to any California foodscape.
White mold, also known as lettuce drop, is a disease that affects far more than just lettuce in your garden.
White mold (Sclerotinia spp.) can remain dormant in the soil for a very long time. It takes a significant amount of cool moisture to wake one of these fungi up from its dormant sleep, but the underside of a head of lettuce, or a cabbage, provides just the sort of humidity needed to trigger an awakening and the ensuing infection. This disease is also known as Sclerotinia stem and crown rot and it is caused by two different fungi, depending on the host plant.
Symptoms of white mold
White mold is seen on outer leaves, lower stems, and pods, in the case of beans. Starting at the base, the mold spreads, causing outer leaves to wilt and fall away from the plant, while remaining attached. Garbanzo beans are particularly likely to become infected in the crown area. Affected plant tissue develops watery lesions as cottony white mycelium form on the surface. Mycelium are the vegetative part of a fungus, made up of threadlike hypha.
Stems may become girdled by the decay. As damaged tissue dies and dries up, it will turn white and looked bleached. Tiny (0.25–0.5 inch), irregularly shaped black flecks, called sclerotia, can be seen on the surface and inside of dead stems. Sclerotia are the resting body of the fungi, made of of a cluster of hyphal threads, and able to remain dormant for a surprisingly long time.
White mold host plants
Along with lettuce and escarole, several members of the nightshade family and the cabbage family are susceptible to white mold. This means that your tomatoes, potatoes, and eggplants, along with Brussels sprouts, mustard greens, broccoli, cauliflower, turnips, radishes, rutabagas, and kale can all become infected. Dried bean plants, alfalfa, other broad-leafed plants, and many weeds can also become infected.
How to avoid white mold in the garden
Since prolonged moisture is needed for this fungus to come among us [sorry, I couldn’t resist], keeping things dry is a good defensive plan. These specific steps can help you avoid a white mold problem in your garden:
As prevalent as white mold is, it’s a good idea to know what to look for ahead of time.
Johnson spot is a fungal disease of rice, wheat, barley, rye, and millet. It also attacks your lawn.
Other names for this disease include rice blast fungus, pitting disease, and ryegrass blast. As a threat to your lawn, Johnson spot can infect kikuyugrass, fescues, rye grasses, and St. Augustine grass.
The fungal pathogen
The fungi that causes Johnson spot is called Magnaporthe grisea (previously known as Pyriculria grisea). Magnaporthe grisea is a highly effective fungus. Spores attach themselves to plant surfaces. They can reproduce both sexually and asexually, and they are prolific. A single spore can complete its reproductive cycle in one week, though it can live for 20 days. Thousands of new spores are generated each night. I don’t know how to calculate the math on all that, but I am certain that those numbers would be overwhelming to a plant. As the fungi perform all that precreation, seed production is reduced and entire leaves are killed.
Johnson spot symptoms
Early signs of fungal infection include white to grayish green spots with dark borders. As they age, the lesions take on a more elliptical shape. These symptoms can be seen on many parts of the plant, including the leaf collar, stems (culms), and flowers (panicles).
How to prevent and control Johnson spot
Moisture is a key ingredient to this fungal growth. If leaves are wet and temperatures are between 77 and 82°F, Johnson spot can quickly take hold. To break this disease triangle, be sure to space plants in such a way that supports good air flow, avoid overhead watering, allow the soil to dry out between waterings (without causing water stress), and only apply the minimum amounts of nitrogen needed by the plants.
Of course, that advice is only partially useful when it comes to lawn care. To help your lawn avoid becoming infected with Johnson spot, water as early in the day as you can. This will allow plants to dry off before evening comes around.
This fungus has developed resistance to chemical treatments, so cultural practices are your only option. These practices include crop rotation, selecting resistant varieties, and disposing of infected plant material in the trash.
Johnson spot is the most significant disease of rice in the world. Experts estimate that this disease destroys enough rice to feed 60 million people every year.
Don’t let the green skin fool you. Greengages are sugary sweet dessert plums.
While most plums tend to be purple to black, and sometimes yellow, with an edge of tang to their flavor, greengage plums are green, and as sweet as candy!
Greengages were first brought to Europe from Iran in the 1700s. George Washington and Thomas Jefferson both grew greengages on their farms, but greengages seem to have fallen out of favor since the 1800s. I do not know why, but I like to think that they are on their way back.
Botanically, all plums (Prunus domestica) are members of the rose family. If you want a cultivar that is descended from the original green Iranian plum, you will need to look for a label that reads Prunus domestica subsp. italica var. claudiana.
Greengages are round or oval pale green to yellowish fruits with smooth-textured, pale green flesh. Greengages are freestone fruits. You may see some varieties with a pale blue blush. Greengages are smaller than mirabelle prune, or cherry plums, but larger than most other palm varieties. There are also some crossbred greengages that may be reddish-purple.
How to grow greengages
Unlike most modern fruits, greengages grow true from seed. This means, if you can find one, you can plant a tree of your own. The original cultivar, now called Reine Claude Verte, remains nearly unchanged from its ancestor. Not all greengages are self-fertile, so you may need to plant two trees to get fruit, spending on the variety. You can grow greengages outside in USDA Hardiness Zones 5-9. Like other plums, greengages love our hot, California summers, and cool, moist winters. You can start a seed indoors any time of year, but bare root trees should be planted January through March. If you don’t have a lot of room, greengages can also be espaliered along a fence.
Caring for greengages
Greengages should be given nitrogen in spring and fall. Amounts vary, depending on tree age, health, and soil. Trees should be pruned while they are dormant, in winter, and again just after fruit is harvested. Thin fruits to 4 to 6 inches apart, for the best quality and to reduce the chances of pest damage or disease.
Greengage pests and disease
Aphids and scale insects are the most common plum pests. Brown rot and shot hole fungus are the most common diseases.
Fruit is ready for harvest June through October, depending on the variety. It in not uncommon to have a bumper crop year followed by a more sparse crop, similar to many citrus trees. They simply do not have the energy or resources to crank out huge crops every year.
See if you can make room for these delicious fruits in your foodscape!
Did you know that there are good grubs and bad grubs?
Before we get started on grubs, let’s clarify the difference between grubs and caterpillars.
Grub or caterpillar?
Grubs and caterpillars are both the larval form of certain insects. They both feed like crazy before transforming into their adult versions. They both have longish, squishy bodies. So, what’s the difference? The difference is in family lines. Caterpillars are the offspring of butterflies and moths, while grubs are baby beetles. There are other differences, as well. Caterpillars have thick, meaty legs, and several of them, while grubs have stubby, ineffective legs (if they have any at all). Also, caterpillars tend to be brightly colored, whereas grubs tend to be white or tan. Grubs are generally one inch long, can feature a dark head, and may or may not have bristles, and they tend to rest curled up in a C-shape.
Bad grubs, such as masked chafers, cutworms, Japanese beetles, armyworms, June beetles, and some weevils, can create brown patches in your lawn and wilting of fruit and vegetable crops. They do this by feeding on roots.
Not so bad grubs
While adult dried fruit beetles can cause problems, feeding on your figs, peaches, and plums, their larvae actually feed on organic material in the soil, helping in the decomposition process, making more nutrients available to your plants.
A while back, I discovered a huge grub population in a raised bed that I use for potatoes. I dug them up (below) and fed them to my chickens. Then I learned that they were green fruit beetle larvae and that they had been making better use of the aged compost I had added to the bed. Ah, well. Live and learn. The chickens were happy.
Since most grubs are root feeders, getting rid of them can help your edibles, ornamentals, and your lawn stay healthy. Hand picking is the most effective method. This means breaking up the soil and picking them up. Breaking up the soil also makes it easier for birds to get their share of those high protein snacks. As much as we would all love easy fixes, products such as diatomaceous earth and white milky spore are not your best choices against grubs. Diatomaceous earth, while it can kill grubs, will also kill off beneficial insects. White milky spore, frequently advertised as a great grub killer, is generally only effective against Japanese beetle larvae, which are not (yet) a real problem here, in California.
Beneficial nematodes can be used against grubs, but the timing must be exactly right for them to do their job. Soil temperatures must be above 60°F, making it the method of choice in summer and early fall, but completely ineffective in spring.
How do you know if you have a grub problem?
Brown patches and wilting can be caused by several factors. The easiest way to see if you have a grub problem is to conduct a drench test. To do this, fill a large watering can or bucket with 2 gallons of water and gently stir in 1/4 to 1/2 cup liquid dish detergent. Then, mark off an area, 3 feet square, with some string. Pour the soapy water evenly over this area. Within 10 minutes, you will see whatever insects are living in that particular piece of soil. If you have a problem, it will be obvious.
As a child, I would eat around the center core of my carrots, leaving the darker, sweeter core for last. I didn’t know it then, but that inner core is called the stele.
Vascular plants have both root and stem steles, but they didn't start out that way. Primitive steles were nothing more than a strand of xylem, surrounded by phloem. [Remember, water and minerals ‘rise up the xylem’ from the roots, and manufactures sugars ‘flow down the phloem’ from the leaves. In case you forgot.]
More modern steles may consist of vascular tissue, pith, and pericycle. Pith is the spongy material seen in the center of stems, and the pericycle is a thin layer of tissue between the xylem and the endodermis. There are two major types of stele: protostele and siphonostele.
Protostele describes the more primitive stele, which consists of a strand of xylem, surrounded by phloem. Protosteles may or may not have an endodermis that controls the flow of water. There are three different types of protostele:
Siphonosteles are a little more complex than protosteles. Siphonosteles may have gaps in their vascular tissue in places where leaves are born. These spaces are called leaf gaps. You can think of these leaf gaps as sections cut from a hula hoop and pulled a little apart, making room for leaf tissue to grow through. Siphonosteles also contain pith. If the xylem is found only outside of the pith, it is called ectophloic. If the xylem can be found both within and outside of the pith, it is called amphiphloic. Members of the nightshade family, such as tomatoes and peppers, are amphiphloic. There are three types of amphiphloic steles:
Diseases of the stele include phytophthora root rot, verticillium wilt, black root rot, and crown rot. In each case, prolonged exposure to wet soil creates the conditions needed for pathogens to infect your plants. Maintaining good drainage and soil structure can help prevent these diseases.
So, why would you care what sort of stele your plants have? Besides sounding really smart, being able to look up information about what’s inside a plant stem can help you identify unknown plants.
What's inside your stems?
With a name like tarantula hawk, you might expect to see some B-movie horror monster soaring out of the sky with eight legs, but the tarantula hawk is actually a spider wasp that hunts tarantulas. It is also one of the most poisonous insects in North America.
Tarantula hawk stings
Tarantula stings are ranked right up their with honey bee stings. Painful, but not debilitating. Tarantula hawk stings, however, are ranked as the second most painful in the world, with the African bullet ant being first. Tarantula hawk stings only last for 3 to 5 minutes, but all you can do during that time is scream bloody murder. Luckily, tarantula hawks do not sting unless provoked. [Apparently, we would be more reasonable to fear the tarantula hawk, than those big, furry spiders.] Unless you are allergic, tarantula hawk stings are not dangerous, just extremely painful.
Tarantula hawk description
There are actually 250 different species of tarantula hawk, worldwide, with 21 species in North America. The most common tarantula hawk found in California is Pepsis grossa, formerly Pepsis formosa. These parasitic wasps are 2 inches long, making them the largest wasps in North America. From above, they look black, with orange wings.
From below, you can see a metallic blue-black abdomen. These bright colors are a warning to potential predators that they might not be worth the effort (aposematism). They have no known predators. Tarantula hawk legs are long, with hooked claws, for grasping prey. Females have stingers that can be more than 1/4 of an inch long.
Tarantula hawk lifecycle
Adult tarantula hawk females hunt tarantulas as food for her offspring. If tarantulas are in short supply, they will also use grasshoppers and other large insects. She captures and stings her prey, injecting them with a paralyzing venom. Then, she brings it to a nest where she lays a single egg on the victim’s body. If this egg was fertilized, it will hatch as a female; if it was not fertilized, it will hatch as a male. Whatever the gender, when the egg hatches, the larva enters the prey and begins feeding. Interestingly, the larva know to leave vital organs of the still living edible for last, to keep everything fresh and delicious. In a few weeks, the larva pupates and emerges from its childhood meal as an adult, and the cycle begins again.
Tarantula hawk diet
Adult tarantula hawks are nectarivorous, which means they feed on nectar and ripe fruit. They feed primarily on the flowers of milkweed plants, and mesquite and western soapberry trees. In some cases, that fruit has become fermented and tarantula hawks can find flying difficult.
Imagine, if you will, a drunk tarantula hawk riding a terrified tarantula, buckaroo style. There may be a movie in there after all…
Did you know that tarantulas migrate each fall? Now you know.
Vedalia beetles are a breed of Australian ladybug that devours their weight in cottony cushion scale pests found on citrus, olives, roses, magnolia, and acacia. The vedalia beetle claim to fame is that it was California’s first attempt at biological pest control
Back in the late 1800s, cottony cushion scale was decimating California’s citrus trees. In 1888, vedalia beetles (Rodolia cardinalis) were imported from Australia to counteract that pest, and it saved the California citrus industry
Vedalia beetle description
Like other lady beetles, vedalia beetles are easy to recognize because of their domed body shape and stubby antennae. The difference being coloration. While bright red lady bugs feature dark spots, vedalia beetles feature a much darker red dome with splotchy black markings. Adults are approximately 1/16 to 1/8 of an inch long and covered with fine hairs that can make them look more grayish than red and black. Larvae are elongate, grayish, and can look like tiny alligators.
Vedalia beetle diet
While the bright red variety most of us think of as ladybugs feeds heavily on aphids, vedalia beetles prefer cottony cushion scale insects. Adult vedalia beetles simply chew up their prey, while younger larvae pierce their victims and suck out their juices.
Vedalia beetles start out as tiny red eggs. These eggs hatch out into tiny red larva. Vedalia larva start feeding right away and they go through several instars, or developmental stages, as they grow. They continue to feed until just before pupating. Then they attach themselves to a leaf as they prepare for their final transformation. [Unlike other insects that pupate, if you touch a healthy vedalia pupa, it should move.] One week later, an adult vedalia beetle emerges, ready to lay 100 to 200 eggs in its 1 to 3 month lifespan.
Combined with a parasitic wasp (Cryptochaetum iceryae), cottony cushion scale is now well under control in California, without the use of any chemicals. Since vedalia beetles are extremely sensitive to pesticides, it is a good idea to inspect an area for these beneficial insects before spraying chemicals.
California red scale is a citrus pest found throughout California, except in Coachella Valley, where an eradication program is in place. These insects may be tiny, but California red scale is a serious pest of citrus trees.
Like other armored scale insects, California red scale (Aonidiella aurantii) have piercing, filamentous mouthparts that are inserted into stems, fruit, and leaves, and suck life-giving sap from your tree. These particular scale insects prefer lemons, limes, Valencia and Navel oranges.
Red scale lifecycle
You will probably never see a tiny, flying male red scale. They only live for about 6 hours and have only one purpose. The females, however, attach themselves to your citrus trees, where they feed on your tree and give birth to 100 to 150 crawlers. Two or three crawlers are born every day to each female. These crawlers leave to their own feeding site. They can also be blown to nearby trees by the wind, or move from place to place by catching a ride on a bird in a practice known as phoresy - though I don’t know if they do it on purpose. Once they settle on a new location, both males and females begin to grow a waxy dome over themselves. Male covers are more elongated, while female covers are more round. Females molt two more times, while males molt under their first dome four times before taking to the air.
Damage caused by California red scale
Chlorosis, twig and branch dieback, fruit loss, and, in severe cases, tree death can all result from California red scale infestations. This damage most commonly occurs at the end of summer, when trees are water stressed and scale populations are at their peak.
How to control California red scale
Scale insects are naturally protected from pesticides. And California red scale has developed a resistance to many insecticides, so, unless you are a commercial farmer or city government, you do not have access to chemicals powerful enough to kill off California red scale. [And would you really want to spray that stuff on your food?] Keeping your trees healthy with regular, deep summer irrigation will reduce water stress. And avoiding the use of broad spectrum insecticides will allow natural predators to do their thing against scale populations. Parasitic wasps and several varieties of lady beetles can provide significant control of scale insects.
Because ants, dust, and poor air flow all make it more difficult for these beneficial predators to find and catch their prey, be sure to prune for good air flow, wrap tree trunks with sticky barriers to block ants, and give your trees an occasional rinse with the hose during the dustier parts of summer. In winter, apply dormant oils.
The next time you go water your citrus trees, take a closer look to see if California red scale has made an appearance.
Beans are easy to grow, they help improve soil structure, and they add nitrogen to the soil. They can also become infected with bean yellow mosaic.
There are three different bean mosaic diseases that occur here in California: bean common mosaic, cucumber mosaic, and bean yellow mosaic. These are all viral diseases that cause downward cupping and wrinkling of leaves, especially as leaves get older, along with the telltale mosaic pattern. Bean leaves that develop a bright yellow mosaic pattern may be infected with the bean yellow mosaic virus. There are several strains of bean yellow mosaic (BYM). In addition to beans, bean yellow mosaic can infect peas, peanuts, soybeans, black locust, and fenugreek.
Bean yellow mosaic symptoms
You can differentiate between bean yellow and the other mosaic infections because bean yellow has a yellow mosaic, rather than a light or dark green mosaic. Bean yellow mosaic also exhibits as bright yellow spots on leaves. Plants infected at an early stage of development can become severely stunted and should be removed from the garden and tossed in the trash.
Bean yellow mosaic lifecycle
The bean yellow mosaic pathogen is called, very unimaginatively, bean yellow mosaic virus, or BYMV, for short. This poorly named virus commonly overwinters in legume crops, such as fava beans, alfalfa, clovers, and vetch, as well as in certain weeds and gladiolus. The virus moves from plant to plant in aphids. When an aphid feeds on an infected plant, it becomes a carrier, transporting the disease to every plant it feeds on from that point forward.
Since resistant cultivars are not yet available, these tips may help prevent bean yellow mosaic in your garden:
Finally, if you see an infected plant, trash it.
With a name like insidious flower bugs, I had to write about them.
These predatory insects are a type of minute pirate bug. They eat many small garden pests and their eggs. And they bite.
Insidious flower bug bites
Yes, insidious flower bugs (Orius insidiosus) bite. We don’t know why. And it hurts. A lot. Some people react to these bites with welts, swelling, or redness, while others have no reaction [other than the pain]. Since these insects are not quick to fly away after biting, you may get some satisfaction out of ending them, but that wouldn’t be in your garden’s best interest. And insidious flower bug bites cannot actually harm you. In fact, they are so tiny that robber flies eat them. [Thanks to Jim Elve for permission to use this amazing photograph!]
Despite their bite, insidious flower bugs really are beneficial. They feed heavily on thrips [their favorite food], corn earworm eggs, mites, spider mites, small caterpillars, bollworms, whiteflies, scale insects, European corn borers, armyworms, potato leafhoppers, and a slew of aphid varieties, including spotted tobacco aphids, corn leaf aphids, and potato aphids. Insidious flower bugs are so beneficial, that they are raised commercially as a biological control against thrips, European red mites, twospotted spider mites, and most aphid varieties in eggplant, strawberry, cucumber, and sweet peppers crops. Research conducted in Florida found that insidious flower bugs were more effective at controlling thrips on sweet peppers than insecticides. Other research has demonstrated similar results with twospotted spider mites on bean plants, and soybean aphids on soybeans.
Insidious flower bug description
These mixed blessings are small, only 1/5 of an inch long. They tend to be flattened, with an oval to triangular shape. They are black with white markings. Nymphs are yellowish-orange to brown, wingless, and teardrop shaped. If you look at an insidious flower bug under a microscope, you can see that they have piercing mouthparts, called beaks, which they use to repeatedly stab and suck the juices from their prey.
Orius insidiosus lifecycle
Insidious flower bugs seem to come out of the woodwork in late summer, though they have been around since they hatched, starting in spring. Eggs are laid in plant tissue, then hatch into nymphs, going through five instars before reaching adulthood. This takes approximately 20 days, and there can be several generations a year. Most of their diet consists of insects and insects eggs, but they occasionally eat plants and pollen when prey is scarce.
Attracting insidious flower bugs
Despite the bite potential, these predators are good to have around. You can attract them to your garden by growing alfalfa, buckwheat, soybeans, cotton, grapes, and most deciduous fruits.
You can reduce the chances of getting bit by wearing dark clothing on hot days in late summer. For the most part, insect repellants do not work against these garden visitors.
Hot summer afternoons are the perfect time to enjoy a nap in a hammock - especially if you are a pumpkin or a melon.
Climbing plants use vines and tendrils to pull themselves ever upward, but they are not always strong enough to support a full sized pumpkin or watermelon. Providing extra support for heavy fruits can allow vines to become far more productive. Supporting fruit in hammocks also helps with pest control and frugal disease.
Growing up and saving space
If you are like me, growing melons and squash is an exercise in space-saving. Melons, pumpkins, cucumbers, watermelons, and cucamelons can all be grown up stock panels, in vertical gardens or towers, or up a fence. Left untrained, these long vines can take over an area. Cucumbers and cucamelons do not need extra support. In fact, cucumbers will grow in strange shapes if they come in contact with anything as they develop. Cucumbers are best allowed to hang naturally. But growing vertically puts a heavy strain on stems and tendrils as fruits get larger. That’s where hammocks come in.
Hammocks, insect control, and fungal disease
Raising fruit off the ground reduces the chance of many insect pests, such as darkling beetles, even finding your crop. At the same time, solid fabric hammocks can also create the perfect hiding spot for earwigs, so it’s a good idea to monitor your hammocks frequently, especially if you are using a closely woven cloth. Getting fruit off the ground also reduces fungal disease. Millions of fungi wait in the soil for just the right conditions - conditions that are created when a melon or pumpkin sits on the ground, creating shade and moisture collection. Great for fungi. Bad for your crop.
How to make melon (and pumpkin) hammocks
You can use an old pair of pantyhose, net onion bags, scraps of hardware cloth or chicken wire, old dishtowels, or old T-shirts to create hammocks for your melons and pumpkins. I have tied strips of fabric around cyclone fencing, sunflower stalks, and stock panels. You can also slip colorful onion net bags over immature fruit and tie or thumbtack the bag to a fence, trellis, or other support. An added bonus to using onion bags - the colors make it easier to find your melons!
Get your melons and pumpkins up off the ground with hammocks!
Every rose has its thorns, right? Well, no. They don’t.
Roses do not have thorns. Roses have prickles. Citrus trees have thorns.
Thorns, prickles, and other spiky bits
Thorns are a type of spinose structure made out of a modified leaf, stem, root, or bud. Many people use the terms bristles, prickles, spines, and thorns interchangeably. Botanically, these terms mean very different things:
So, where bristles are stiff hairs and prickles are hard, spiked skin (neither of which contain plant veins), spines, being modified leaves, and thorns, modified stems, do contain plant veins.
Plants use thorns as a mechanical defense against herbivores (and gardeners). Cacti are far less likely to be eaten when they are covered with hard thorns. And the pollinators who specialize in pollinating these particular types of plants seem to be unaffected by the presence of thorns. In some cases, thorns are also used to shade certain plant varieties, or to provide a layer of insulation.
Home, sweet thorn
Some thorns are hollow. These tiny chambers are called domatia. Plants, such as certain acacia species, produce domatium to provide shelter for beneficial arthropods (insects, spiders, and crustaceans). Similar to galls, which are produced by the resident, rather than the landlord, domatium are the plant’s side of a mutually beneficial relationship, most commonly with ants or mites. Occasionally, thrips may also move into these tiny apartments, but they are generally unhelpful to the plant. The plants that create these thorny thresholds are called myrmecophytes.
While I do not expect any of you to stop calling rose prickles thorns, why not impress your friends with your new-found knowledge?
Onions, chives, and garlic plants with pink roots are not happy.
This disease rarely causes significant problems in garlic, but it can shrink your onion and chive harvest by quite a bit.
The pink root pathogen
Pink root is caused by a fungi called Phoma terrestris. Phoma terrestris is nearly always present in the soil and it pretty much lasts forever. Normally, it causes no serious problems. If your onion plants are weakened by drought, insufficient or excessive fertilizer, water stress, insect feeding, compacted soil, or any number of other less than ideal circumstances, your onions may become susceptible. This pathogen thrives in temperatures between 75° and 85°F and can be moved around the garden by splashing rain or water, and on tools.
Symptoms of pink root
Aside from the obviously pink roots, plants infected with this fungal disease also exhibit roots that darken to red, purple, and, eventually, black. These roots shrivel up and die. These discolorations may move up into the bulb. This infection leads to stunting, but it rarely kills the plant. This disease looks a lot like fusarium wilt.
Preventing and controlling pink root
Keeping plants healthy and employing crop rotation are the two best ways to avoid pink root from causing too many problems. A note on crop rotation: do not follow a cereal crop with onions, as it creates conditions that promote this particular pathogen. Severe infestations can be eliminated with soil solarization, but that’s a pretty drastic measure for the home gardener.
If you see pink, purple, or black shriveled roots on your onions, try growing them in a different area, in fresh soil, and be sure to feed, weed, and water them properly, and protect them from insects, to ensure that they stay healthy enough to protect themselves.
If the lower limbs on your almond tree are turning brown, you have a problem.
While it is normal for the leaves on lower limbs to turn yellow because of being shaded by the limbs and leaves above, lower limb dieback (LLDB) goes much farther and can result in the death of your tree. LLDB first appeared in 2005. Scientists do not yet know what causes this condition, but learning how to avoid it can save your trees.
Symptoms of lower limb dieback
This disease normally appears in late April or May, on trees that are 7 or 8 years old. It starts out with the leaves on lower limbs yellowing, and then turning brown. Eventually, the entire branch becomes girdled by cankers and dies, right up to where it attaches to larger, scaffold branches, or the trunk. If you scrape the bark off of an affected limb, you will see brown spots in the wood. [Sorry, but I couldn't find an image I could use.]
Some almond varieties are more susceptible to lower limb dieback than others. Padre almonds are the most likely to get this disease, with Butte being a close second. Almond varieties that show some resistance to lower limb dieback include Aldrich, Carmel, Fritz, Mission, NePlus Ultra, Nonpareil, Sonora, and Wood Colony. If you are shopping for an almond bare root tree, you might consider one of these more resilient varieties.
Preventing lower limb dieback
While research is currently underway, it is believed that overly wet soil, low light levels, and root exposure to herbicides or excessive fertilizer may weaken trees, making them vulnerable to whatever it is that causes this problem. This is just the opposite of shade tree decline, in which severe drought slowly kills a mature tree, with the early symptoms being a lack of leaf cover in the upper canopy, or crown, of the tree.
Lower limb dieback occurs most often in years with a cool, wet spring, followed by high temperatures. Soil compaction and low infiltration rates are also believed to play a role in lower leaf dieback. Trees with hull rot also appear to be more likely to develop this condition. In this case, fumaric acid and other toxins are believed to accumulate in larger branches when multiple spurs are infected. In this weakened state, these trees are also more likely to be infected by fungal opportunists, such as Botryosphaeria dothidea and Phomopsis amygdali. Phomopsis amygdali causes the stoma to stay open, desiccating the tree. Botryosphaeria dothidea causes cankers on a wide variety of plants.
Keeping your trees healthy is the best way to prevent lower limb dieback. This means proper irrigation, reasonable applications of fertilizer (only after a soil test shows a need for it), and control of scale insects, which may play a role in the spread of this disease. Fixed copper, sulfur, and fungicide treatments have not been shown to be effective.
Geocarpy is a rare form of plant reproduction that practiced by peanuts and a few other plants you may, or may not, recognize.
While most plants wave their flowers at pollinators and then allow their fruit to swing freely, out in clear view, geocarpic plants are far more modest.
Geocarpic plants tend to live in areas that are harsh. Seasonal fires, extreme drought, and repeated freezing and thawing (solifluction) can make plant life difficult. Because of all this uncertainty, these plants have decided that it is better to push their flowers underground to develop into fruit. The floral stem, or peduncle, does all the pushing.
Types of geocarpy
The term geocarpy refers to any plant that ripens its fruit underground. There are three forms of geocarpy: hysterocarpy, amphicarpiy, and protogeocarpy. If the ovaries are fertilized above ground and then pushed underground, it is called hysterocarpy. Peanuts are hysterocarpic. If only some of the fruits are pushed underground, it is called amphicarpic. Protogeocarpic reproduction is really wild. These plants produce their flowers underground. Think about it. How are pollinators supposed to transfer pollen to the flower if it is underground?
Protogeocarpic plants have evolved a different type of flower. The stigmas, or pollen receptors, of protogeocarpic flowers push their way an inch or so above ground. Pollinators land on these threadlike, aerial stigmas, depositing pollen, which then travels down the stigma to the flower, underground. Here, the ovary is fertilized and fruit development occurs. I’m not sure why they have those names, but I like to think of plants waving their aboveground flowers ‘hysterically’ before heading underground, to remember which one is above ground.
In addition to peanuts (Arachis hypogaea), South African bitter cress (Cardamine hirsuta) and the Genuflecting plant (Spigelia genuflexa) also use this unique method of reproduction.
Do you have any geocarpic plants in your garden?
You may be surprised to learn that potting soil is not really soil at all.
Potting soil, also known as potting mix and potting compost, has been used by gardeners since the 1800’s, and there are many good reasons for doing so. First, let’s find out what, exactly, is in potting soil.
Potting soil ingredients
Potting soil is a manmade recipe often made out of composted bark, sand, perlite, peat, recycled mushroom compost, and mineral nutrients. These mixes are treated to create the best pH for plant growth. Some potting mixes contain slow-release fertilizers. You can find potting soil that is rated ‘organic’ according to OMRI regulations, and you can find potting mix that includes ground up old car tires. It’s one of those cases where you really do get what you pay for. If you are committed to organic gardening, be sure to look for the OMRI label.
Potting soil’s unique properties
Potting soil is designed to retain moisture and nutrients. [Because of this ability, fungus gnats are often attracted to pots filled with potting soil - it’s the moisture.] Potting soil is also sterilized to kill off pathogens and weed seeds. This is what makes it so useful in container gardening. Some potting soil mixes are designed for specific plant species, such as African violets or cactus. Fresh potting soil is also what keeps your window sill garden and holiday plants healthy and productive. Stale potting soil… not so much.
How to recondition potting soil
Old potting soil may not actually contain anything useful to your plants. Like garden soil, nutrients are ultimately depleted and must be replaced. Also, potting soil, in particular, becomes hydrophobic as it ages. This means that it actively repels water, allowing it to quickly drain out of the bottom of the contain, leaching valuable nutrients as it goes. You can either dump it out and buy new potting soil, or you can recondition what you have. To recondition old potting soil, simply top dress it with aged compost and water it in. No digging or repotting needed. Also, you can apply an attractive mulch of wood chips on top of your potting soil to act as a slow release of organic material and some nutrients.
Uses for potting soil
Because of its ability to retain water and nutrients while providing ideal soil structure, potting soil is the best choice for seed starting, transplanting, and up-potting. The loose potting soil is gentle to traumatized root hairs and eases the transition. Potting soil is also the best choice for vertical gardening, tower gardening, and raised beds.
If you love your trees (or your blueberries), be on the lookout for Asian longhorned beetles.
Native to China, Japan, and Korea, these invasive, wood boring beetles love to hitch overseas rides on wood-related packing materials: shavings, pallets, that sort of thing. In 1996, an infestation of Asian longhorned beetles (Anoplophora glabripennis) was discovered in Brooklyn. Two years later, a second sighting occurred in Chicago. Then, they were found in New York, New Jersey, and Illinois, where they are responsible for the removal of thousands of trees. These pests have already cost state and federal government (our tax dollars) over $168 million and that number looks to rise exponentially, now that they have expanded their range into California and Washington.
The potential economic impact was first estimated to be more than $41 billion. That number has increased to nearly $700 billion, and that’s before you factor in the damage to breakfast morale when the northeast’s sugar maples are attacked! Eradication efforts got into affect each time these invasive pests are found, sometimes successfully, sometimes not. The U.S. Customs Department is working hard to halt the importation of these pests. Eradication in the U.S. is still possible, but it’s an uphill battle. And they need our help.
Asian longhorned beetle identification
Asian longhorned beetles (ALBs), also known as starry sky or sky beetles, are easy to identify. Approximately one inch wide and and an inch-and-a-half long, they are shiny black with 20 white spots on each wing cover, and they feature an impressive set of black and white banded antennae. They have long, whitish-blue feet and large mandibles. Larvae are large and cream colored.
Adult female beetles chew pits into wood and then deposit their eggs into those pits, one at a time. She can lay up to 90 eggs in just a few weeks.
When the eggs hatch, larvae tunnel deep into the tree (where they are safe from predators and pesticides), leaving behind a trail of frass. Deep within the tree, the larvae go through several instars before entering a pupal stage.
As adults, they tunnel out of the tree, leaving 3/8-inch exit holes along trunks and branches. Piles of frass can be seen at the base of infected trees and in branch crotches. Branch dieback and leaf wilting are early signs of infestation. The egg sites and larval feeding make the trees susceptible to many other pests and diseases, as well as more vulnerable to damage from heavy winds. Sap is often seen oozing from wounds. This larval tunneling causes extensive damage and girdling, making the wood unusable and eventually killing the tree. Infested trees must be removed and destroyed by trained professionals. Do not attempt this yourself.
Trees susceptible to ALB
Many popular hardwood trees are vulnerable to ALB infestation. These trees include alder, ash, beech, birch, boxelder, elm, hackberry, hornbeam, horse chestnut, mimosa, planes, poplar, sycamore, and willow. And blueberries! And members of the Prunus family, which includes apricots, peaches, nectarines, cherries, and almonds! We do not yet know what the impact will be on California’s native hardwood trees.
Experts predict that this pest could cause more damage than gypsy moths, Dutch elm disease, and chestnut blight combined, destroyed millions of acres of trees across the country, in parks, along streets, in backyards, and in agriculture. Dead and dying trees are more likely to cause fires and they are unable to support the biodiversity that keeps a region healthy. If you consider all the wood-based products we use every day, ALB could cause many prices to increase significantly. All because of an insect.
If you see it, catch it! Report it!
If you see an Asian longhorned beetle, catch it. Period. Just do it. They don't bite or sting. While they can fly, they don’t do it very well and only for short distances. You can do this.
Your efforts could save millions of trees and billions of dollars. Seriously.
Put your captive in a glass jar [they chew through trees, remember?] and place it in the freezer. Be sure to label the jar with where you found it (GPS position, if possible), the date you found it, and your contact information. These reports are critical if we are to protect our trees. Using this information, experts can create quarantine zones and implement eradication programs most effectively.
If you live in California, call the CDFA hotline at 1-800-491-1899. In fact, put the number in your phone now, so you’ll have it if you ever need it. I did. If you live outside of California, report it to your state’s Department of Agriculture. Together, we can save millions of trees.
You can grow a surprising amount of food in your own yard. Ask me how!