Western grape rootworms are leaf beetles that eat the leaves of grapes, roses, and fireweed in spring and summer. If that weren’t bad enough, their offspring are found underground, chewing up the root system. The combined effect can be devastating.
Western grape rootworm description
These beetles are very small, averaging only 1/7” in length. This works out to 4 or 5 beetles standing end-to-end across a dime.
Unlike their more tan-colored cousins, western grape rootworms are usually black or reddish-brown with dull gray, yellow, or white hairs, and orangish-red antennae. Larvae are 1/4-inch long, C-shaped white grubs. These grubs have 3 pairs of prolegs, a reddish brown head, and black or brown mouthparts. Eggs are laid in clusters on old wood under loose bark.
Male western grape rootworm beetles rub their legs together to attract females, the same way crickets and grasshoppers do each summer.
Damage caused by western grape rootworms
These beetles cut slit-like holes in leaves, shredding them to tatters. The leaves then dry up and die, reducing photosynthesis and food for the plant. Adult beetles may also be found feeding on berries, petioles, and the bark of new shoots. Underground, western grape rootworm larvae feed extensively on the root system and can cause considerable damage.
Controlling western grape rootworms
Since larvae spend most of their year 2-feet underground, control is generally only possible during spring, when larvae and adult beetles move to the surface. Monitor plants for signs of beetle feeding and handpick whenever possible. You can also use sticky barriers to capture beetles moving up and down the trunk.
If you see a tiny beetle playing ‘possum, don’t be fooled. The western grape rootworm beetle uses that trick to avoid being eaten, often falling off a leaf, stiff-legged.
With a name like Asian jumping worms, you might expect colorful, flamboyant gymnastics moving gleefully through the soil, helping your plants grow.
Okay, that was a stretch. And you’d be mostly wrong.
I say mostly because, while not colorful, these worms really can move. Also known as snake worms, crazy worms, and Alabama jumpers, Asian jumping worms writhe violently when disturbed. They can even drop their tail when threatened.
Sadly, instead of helping plants grow, these voracious feeders strip an area of nutrients, destroying the top soil layer, and leaving desolation in their wake. This interrupts thousands of years of evolution and nutrient cycling, threatens biodiversity, and increases erosion.
The invasives mixed bag
Before we get into the Asian jumping worm story, let me remind you that our beloved European nightcrawlers and honey bees are also non-native species. Sometimes invasives can be a good thing. This is not one of those times.
As with many other situations involving invasive anything, the problem lies in imbalances. North American forests and farmlands have evolved, over thousands of years, to use surface plant litter as slow-release food and secure habitat for countless microorganisms, insects, reptiles, amphibians, and other life forms. Asian jumping worms eliminate that layer and they do it very quickly.
What are jumping worms?
Our more sedate earthworms tend to be reddish brown with a raised white or grey partial band part way down the body. That band is called the clitellum. Asian jumping worms, which can range from 3 to 7” long, are grey to dark brown, with a smooth the clitellum that goes all the way around and is closer to the head end.
Also, while shiny, jumping worms do not produce the slime seen on many earthworms. Regardless of how you feel about that slime, it is very useful in creating soil aggregates that allow for the healthy movement of air, water, microorganisms, and roots through the soil. Jumping worms also tend to be more rigid than our squishy earthworms.
There are three species of Asian jumping worm: Amynthas agrestis, A. tokioensis and Metaphire hilgendorfi, with A. agrestis being the most commonly seen. Native to Southeast Asia, jumping worms are believed to have been brought to North America in potted plants, bagged soil, or nursery stock, though we don’t know exactly when or how.
Asian jumping worms have moved quickly westward, in worm terms, over the past 10 years and are now found in Oregon. As you can imagine, these continued movements are not just worms traveling on their own. Asian jumping worms end up in plants, mulch, and soil, on shoes and equipment, in agricultural produce, and in batches of fishing bait. They get transported by us, one gets loose, the problem spreads. It’s easy to do because these jumping worms spend their winters as tiny, pinhead size cocoons, filled with eggs, they reach adulthood twice as fast as our familiar earthworms and red wigglers, reproduce more rapidly, and are more aggressive. They can also thrive in higher densities and eat a wider variety of foods.
The real problem with Asian jumping worms is where and how fast they feed.
Damage caused by Asian jumping worms
Asian jumping worms are too efficient. That may sound like a good thing, but too much of a good thing can be a bad thing. Let me explain.
As earthworms feed on fungi and bacteria that grow on decomposing organic material, they burrow into the soil, excreting castings that are filled with broken down plant and animal material, churning the soil and improving soil structure, soil health, water retention, drainage, and nutrient cycling. Everybody’s happy. Plants and organisms grow. Life goes on.
Asian jumping worms are eating machines, quickly devouring all of the surface material in an area and leaving behind a trail of low-nutrient crumbles prone to serious erosion. Research has shown that jumping worm castes are different from those of other worms. Instead of the soft, brown, crumbly bits of plant food and soil amendment we associate with earthworm castings, Asian jumping worm castings look more like a pile of coffee grounds.
Asian jumping worms process nutrients so rapidly that their feeding releases nutrients faster than plants can absorb them, causing the nutrients to be washed, blown, or leached away. These castings contain important plant nutrients, such as potassium and calcium, and they tend to contain higher levels of heavy metals, such as iron and aluminum. When those crumbles are eroded away, those nutrients are lost. As a result, Asian jumping worm feeding quickly converts healthy, loamy soil in to granular, more sandy soil that tends to be hydrophobic, which means water runs off instead of sticking around long enough for plants to absorb. These invasive worms also push nutrients so deeply into the soil subsurface that many shallow-rooted plants cannot reach those important nutrients, leaving them to starve.
What can you do about jumping worms?
In a word, be diligent. Asian jumping worms generally cannot survive freezing winters, but anything less than that and they can become a serious problem in your yard. You can help prevent the spread of these invasive worms with these handy tips:
Bottom line, earthworms create topsoil while Asian jumping worms destroy it. Of course, that’s an oversimplification, but I want you to understand how important it is that these pests are kept in check.
If you suspect the presences of Asian jumping worms in your garden, conduct a mustard test using these steps:
Hollyhocks are probably not your first thought when it comes to edible gardening, but these tall, bold beauties of our grandparents’ time may surprise you.
First, did you know that all parts of a hollyhock are edible? My chickens may not share that world view, but we frequently differ on menu items.
In addition to being edible, hollyhocks are surprisingly useful plants. Hollyhock stems make excellent starter firewood, and the roots have been used for centuries as medicine. While I do not make any medical claims about plants, research has shown that infusions of hollyhock roots may reduce stress. I’ll leave that to you.
Let’s see what else we can find out about these durable garden flowers.
Hollyhocks are members of the mallow family. Native to Europe and Asia, there are 60 or so species of hollyhock, or Alcea, with Alcea rosea being the most commonly grown. The Alcea genus includes all the hollyhocks, except for one species that is native to the western hemisphere, the streambank wild hollyhock (Iliamna rivularis).
While the streambank wild hollyhock is in a different genus, the blooms are still lovely. For this post, we will be focusing solely on Alcea hollyhocks.
Hollyhock flowers are impressive. Growing along the stalk like flagrant Brussels sprouts, large hollyhock blooms can be pink, red, apricot, raspberry, bluish pink, white, purple, or yellow. Their sturdy, unbranched stems can be equally impressive, rising 3 to 10 feet in the air, depending on the variety. There is even a nearly black cultivar, called ‘Creme de Cassis’.
Broad leaves may be toothed or lobed and grow on long stems called petioles. Both leaves and stems are generally covered with star-shaped trichomes, or hairs. While those hairs may irritate your skin, if you are sensitive, it is the hollyhock flower that grabs our attention.
Caring for hollyhocks
Hollyhocks are not particularly picky. They grow best in Hardiness Zones 3-8, can be grown in full sun or partial shade, and prefer good drainage. The only thing hollyhocks do not seem to like is dry soil. Here in California (Zone 9b), dry soil is the rule in summer, but a thick layer of arborist chips mulched over the area and planting them in a relatively protected corner of the yard seems to be help enough and they return every spring to fill my summer with gorgeous flowers. Being near a fence or trellis also protects these tall stems from wind damage.
To keep your hollyhocks healthy, cut stems back to 6” or so above soil level after flowering is completed. Continue to top dress and irrigate the area and new stems will appear throughout the growing season. In winter, cut plants back again and protect with a 6” layer of straw or mulch. Come spring, gradually remove this protective layer to help plants become acclimated. Once spring growth is in full swing, remove the straw and start thinning.
By removing the cut stems from the area and composting them, you will interrupt the disease triangles and thwart pests of hollyhocks.
Hollyhock pests and diseases
On the downside, like other members of the mallow family, hollyhocks are prone to mildew and rust and will attract weevils, mallow flea beetles, and orange tortrix moths. The caterpillars of a few other moths and butterflies, including painted ladies, will also chew on hollyhock leaves, as will slugs and snails, spider mites, and Japanese beetles. Aphids, capsid bugs, and cutworms may also cause problems.
Because they are prone to rust and mildew, hollyhocks should always be watered at ground level. Wet leaves nearly always attract disease. Diseased leaves should be removed and thrown in the trash whenever they are seen.
Hollyhocks and children
Hollyhock seeds are large and easy to work with, making them a good choice for a children’s activity. Hollyhocks do not like being transplanted, so it is better to sow seeds where you want them. A hollyhock’s long taproot doesn’t like being disturbed, once it begins its downward growth.
Traditionally, hollyhocks have been used to create secret garden spaces for children and solitary readers. Simply draw a line where you want you secret hideaway’s walls and plant seeds along that line. Seeds should be planted in groups of 3 or 4, placed 2 to 3 feet apart. Only cover lightly with soil, if at all, and keep the area moist but not soggy until germination occurs. Thin each group by snipping off all but the best one seedling at ground level. They may look tiny and lonely, at first, but these plants get large and need good air flow to stay healthy.
Before you know it, you will have a secret garden space of your very own, attended by the many bees, butterflies, hummingbirds and other pollinators that love hollyhocks as much as we do!
Worms, or wyrms as they were originally called, don’t technically exist.
Wyrms referred a huge collection of tubular, limb-less critters back in the 1700’s. Of course, we all know what I mean when I say worm, right? Sure, we’ve all seen earthworms and red wigglers. But what about the 3-foot bristle worms, or the 22-foot African giant earthworm, or, are you ready for it? What about the 190-foot oceanic bootlace worm?!!? Crazy, right?
Well, clearly, we don’t ave any 190-foot worms in our gardens. What we do have is long, squishy bodies that are easier to describe by what they don’t have. Worms do not have legs, true limbs, scales, lungs, a brain, a true digestive system, or a circulatory system. They breath through their skin, which needs to be moist at all times. Dehydrated worms become paralyzed.
You may be surprised to learn that many worms are not actually able to move themselves with muscles, the way we do. Instead, they move through the soil by the act of feeding. If you think about it, worms are one big food tube. Food is sucked into the mouth and passes through a pharynx, esophagus, crop, gizzard, and intestine, before being pushed out the other end. While worms do not have eyes, per se, some of them do have light sensing organs.
Types of garden worms
There are three different types of garden lifeforms that fall under the worm category:
Nematodes are round worms. Earthworms are segmented. And flatworms, such as land planarians are, well, flat. The flatworms and roundworms are known as helminths and tend to be parasites of one form or another.
Worms improve soil
Worms are an important part of decomposition, whether it is happening underground or in your compost piles. Worms improve soil structure and soil health, making life a lot easier for your plants. As worm populations increase, drainage and porosity, or permeability also improve.
As worms eat, poop, and die, they create mucous-coated soil clumps, or aggregates, that have spaces for water, roots, and air to move through. These spaces, called macropores and micropores, are important factors in soil health. For example, in sandy soil, the spaces are very large and leaching can be a problem, while clay particles are very tiny and they hold tightly to water and nutrients, and often have compaction problems. Worms help offset those problems by helping to break down and decompose organic materials, improving soil structure, adding nutrients, and being part of the nitrogen cycle. Worms are an important part of the soil food web and they help keep plant and tree roots healthy.
Food for worms
Did you know that earthworms like coffee? It ends up that sprinkling coffee grounds around your yard is a good way to reduce compaction and a couple of fungal diseases. For some reason, worms tend to pull coffee ground deeper into the soil. We don’t know why. We do know that worms will eat dead plant material, insects, insect eggs, fungi, bacteria, dead animals, and even cardboard and paper.
While we may all end up as food for worms, more often than not, it is the worms who become the entree. Worms are commonly eaten by birds, amphibians, reptiles, and many mammals. Skunks, moles, shrews, raccoons, and rats will all gobble a worm, given the opportunity, as will centipedes, beetles, and even other worms, such as land planarians.
Worms that are not worms
Caterpillars, such as the impressively large Achemon sphinx moth, carpenterworm, and tomato hornworm larvae are commonly referred to as worms, as are tiny pink codling moth larvae, apple maggots, armyworms, cutworms, inchworms, naval orangeworms, and destructive green cabbageworm larvae, as are the microscopic larvae of dryberry mites. The larval form of click beetles are also called wireworms. And some people call grubs worms, too, but I have no idea why Each of these not-worms is simply a developmental stage in a process of metamorphosis..
Help the worms in your yard
Worms do not have much of an arsenal when it comes to defense. The best way to help the worms in your yard is to create a healthy environment that meets their needs. If you build it, they will come. These tips will help you create a worm-friendly habitat in your yard:
If you happen to use tower gardening or other containerized methods, you can always rescue a few worms stranded after a rain and add them to the pot. They and your plants will be better of! And if worms really fascinate you, you can also raise your own. This is called vermiculture.
Your yard may look quiet on the surface, but there is a lot going on underground. Even when given time to rest, or go fallow, there are still billions of processes happening in the soil beneath your feet, and worms are an important part of those processes.
Finally, there is a new threat in the world of soil organisms. This one is the Asian jumping worm. There will be more on that soon.
Long, long ago, there were no flowers.
It wasn’t until the Cretaceous period, some 130 million years ago, that a handful of renegade cone-bearing gymnosperms started protecting their naked seeds with a new structure. This new, flimsy bit of color was so successful at boosting pollination rates that it spread far and wide, making flowering plants (angiosperms) one of the most successful types of plant life on Earth.
That structure is the petal.
Of course, that’s a pretty big claim for such a delicate flap of plant tissue. Too frequently discounted as an unimportant fashion accessory to more vital, functional parts of plant anatomy, there is far more to a flower petal than meets the eye!
Before we get to the really astounding stuff, let’s make sure we know what we are talking about when we talk about petals.
What are petals?
You may be surprised to learn that petals are modified leaves. In fact, sepals, stamens, and carpels are all genetic twists on the leaf. As a modified leaf, a petal has a broad, flat area called a blade. At the narrow end, where the petal attaches to the plant, is the claw, which is very similar to a petiole, or leaf stem. Where petals are attached to one another is called the limb. The petals that make up a flower are called its corolla.
Just under a collection of petals is another set of modified leaves, called sepals. Sepals are usually green. When discussing the combined petals and sepals of a flower, it is called the perianth. When sepals and petals are indistinguishable from one another, they are called tepals. [Aloes and tulips are tepals.] Sometimes, sepals look more like petals than leaves. When that occurs, they are said to be petaloid.
Petals of parentage
The number of petals present in a flower, the way the petals are arranged, whether or not they are fused to neighboring petals, or how much they are fused, as well as color are used by pollinators to find the pollen and nectar they seek. We can use the same information to identify unknown plants
First, flowers with 3 or 6 petals tend to be monocots, while flowers with 4 or 5 petals, or groups thereof, are most often eudicots, though not always. Petal arrangement, or floral symmetry, can also help with plant identification:
Petals, in particular, evolved to protect the reproductive part of a flower and to attract or repel specific pollinators. We know that flowers come in every color imaginable, but did you know that they also feature colors we cannot see, with glowing flight lines, traffic patterns, and welcome mats? It’s true! Flowers exist to attract the type of pollinator that will help them to procreate their species. Not all pollinators are created equally. It is a waste of resources for a plant (or any living thing) to attract the wrong sort.
The story of floral scent
Orchids produce floral scent in specialized sacs, but most flowers get their scent from chemicals produced by the petals. While many of us, along with most insect and bat pollinators, find floral aromas appealing, herbivores and disease-carrying insects often disagree with that evaluation. Combined with the colors, petal arrangement, and floral placement, floral scent works to increase a flower’s chance at becoming pollinated and/or fertilized.
Did you know that plants use floral scent to communicate with each other? It’s true! The volatile chemicals that give a flower its fragrance trigger a behavioral response in a surprising number of neighboring life forms and no two floral scents are identical, sort of like snowflakes.
Sensing a reproductively fertile neighbor, another flower may shift its chemical production to attract pollinators of its own. On the other hand, a fertilized flower will often release ethylene, a ripening agent, to discontinue the scent so that local pollinators will turn their attentions to neighboring flowers in need of pollinating. Also, injured flowers produce different scents than those being chewed on by herbivores. We can’t see it or smell it, but it’s going on all the time.
In the world of botany, a cane can refer to a stalk of bamboo or other grass, a reed, sugar cane, or new growth on a grape vine. Canes are also used to refer to blueberry, currant, rose, and kiwi stems, but we will leave them out for the sake of this discussion, which is more accurately geared toward blackberries and raspberries.
Canes are the long, arching stems of perennial bramble fruits. These canes are filled with spongy pith and normally covered with sharp prickles. Because of those sharp points, bramble canes have traditionally been used in pleaching. Pleaching is method by which living bramble are cut in half, bent over and woven together. As the canes repair themselves, they create a dense, prickly barrier that few thieves or predators would care to cross.
Brambles have perennial roots and crowns that grow new canes each year. New green canes are called primocanes. They turn brown and go dormant over the winter, to one degree or another. In spring, these now 2-year old canes are called floricanes. Flowers and fruit are only produced on floricanes, so you don’t prune them out. Once fruit set has occurred, canes should be allowed to die back before being removed.
Cane growth forms
Raspberry and blackberry canes can grow in one of two forms: erect or trailing. Erect brambles have stiff canes that arch. While not completely self-supporting, erect brambles tend to grow into huge thickets if not pruned. Trailing blackberry cultivars, also known as dewberries, will spread horizontally across the ground. If you live in a cold area, there are even late-season blackberry varieties that can produce late summer crops. The University of California provides an excellent list of blackberry cultivars.
Cane fruit production
Cane fruit production varies between everbearing and summer-bearing varieties. Summer-bearing canes bear one crop in summer on two-year old canes, while everbearing cultivars have two crops, one small crop in summer on new canes and one heavier crop in fall on two-year old canes. Everbearing cultivars are sometimes called fall-bearing. It is a good idea to check with your local Cooperative Extension Office to find the best cultivar for your location.
Brambles can easily be propagated by a method of layering called tip layering. Tip layering consists of digging a small hole, 3 or 4 inches deep, and putting the tip of a cane into the hole and covering it with soil. At first, the tip will grow downward. Then, it will complete a U-turn in the soil and emerge above ground. That bend will develop roots, allowing the new plant to be separated from the parent plant in spring and replanted elsewhere.
New canes should be trimmed to a 6” height. First-year canes can be pruned to a manageable size with renewal pruning, or trained onto a trellis. Stimulate lateral (fruit-bearing) growth by tipping, or cutting off the ends. When working in bramble canes, it is a good idea to wear long sleeves, long pants, and heavy gloves. Those prickles are sharp!
Pests and diseases of canes
Canes are susceptible to a number of different pests and diseases. Bacterial diseases, such as crown gall, viral diseases, such as tomato ringspot, and a slew of fungal diseases, including a number of blights, such as petal blight, spur blight, and cane blight, along with leaf spot, anthracnose, rust, and Verticillium wilt may also appear. If that weren’t bad enough, treehoppers, raspberry cane borers and another type of borer called the rose stem girdler, along with sawflies, lygus bugs, raspberry horntails, vine mealybugs, leafrollers, and tortricid moths (leaf roll) may feed on or damage bramble canes. For all those threats, canes are durable plants, once established. You do need to monitor for environmental conditions, such as dieback, insufficient calcium combined with infrequent irrigation, iron deficiencies, and sunburn damage.
Whichever cane fruit you decide to grow, you will receive many, many years of delicious summer fruits with surprisingly little effort. Just watch out where you plant them, they can spread!
The Daily Garden is all about plant vocabulary. Today, we are looking at overall plant anatomy because it can be difficult to talk about something if you don’t know the words.
By taking a closer look at plant anatomy, we will be better able to understand each other, we can get more out of plant descriptions, and be better able to identify those mystery plants that always seem to pop up in the yard.
Plant anatomy, or phytotomy, starts with simple descriptions of the outside and inside of plants. Remember those black-line masters from grade school used to teach parts of a plant? Well, let’s start there.
Basic plant systems
Plants are have two basic systems: roots and shoots, with the root system below ground and the shoot system above ground. Roots provide anchorage and often store nutrients. Roots can develop as a taproot or fibrous root system. Roots have hairs that absorb water and nutrients. The shoot system consists of vegetative parts (leaves and stems) and reproductive parts (buds, fruits, seeds, and flowers or cones). Let’s take a closer look at each of those parts.
Leaves are the sugar factories of the plant world, absorbing sunlight and converting it into sugar through photosynthesis. The wide, flat part of a leaf is called the blade, or lamina. The shape of the leaf blade is very useful in plant identification, as is the way those leaves are arranged along a stem and the pattern of veins within a leaf. The edge of the leaf is called its margin. Leaves are coated with a waxy protective cuticle. There are tiny holes, usually found on the underside of a leaf, called stoma, that allow plants to exchange gases with the environment and to regulate water flow within the plant. The stem that connects a leaf to a stem is the petiole. Leaflike structures seen at the base of the petiole are called stipules,
Stems support leaves, flowers and buds. These structures are attached at nodes. The spaces between nodes are called internodes. Herbaceous stems have waxy cuticles for protection while woody plants have bark. Stems contain a vascular system that consists of the xylem, phloem and may include a cambium layer. This system carries food, water, and minerals throughout the plant. That vascular system is arranged in a circular pattern in dicots and eudicots, while it is more scattered in monocots. Twigs are woody stems from the previous year. Branches are more than one year old and may have lateral stems. Trunks are the main stem of woody plants, such as trees and shrubs. Canes are a type of stem filled with spongy pith. Canes generally only live for a year or two. Modified stems occur both above and below ground. Bulbs, corms, rhizomes, and tubers, such as potatoes, are below ground modified stems. Crowns, spurs, and stolons are aboveground modified stems. Thorns are also modified stems, but rose thorns are not really thorns. They are prickles, which are modified epidural, or skin cells. Stubby stems, called spurs, produce fruit buds.
Buds are shoots that may develop into leaves or flowers. Buds are identified by their location on a stem: lateral buds are found along the sides of a stem, while terminal buds are found at the end. Lateral buds usually grow where leaves meet the stem and are called axillary buds. Renegade adventitious buds may show up at injury sites, on roots, or even at the edge of a leaf. The place where buds fall off leave a mark called a bud scar. Tree leaf buds have scales, while leaf buds of annuals and herbaceous perennials have delicate naked buds. Potato eyes are clusters of buds.
Fruits are ripened plant ovaries. Fruits can be simple (formed with one ovary), as in the case of stone fruits, or compound (formed with several fused ovaries). Compound fruits can be multiple or aggregate. Apples and other pomes are multiple compound fruits. You can tell by the 5-pointed star shape in the center of the fruit. Raspberries, which are drupes, not berries, along with pineapples and figs are formed by many flowers fusing together and are called aggregate fruits. By the way, strawberries are not berries, either. They are ripened receptacles. Berries, such as pumpkins, cantaloupes, cucumbers, eggplants, and tomatoes, all have many seeds inside an outer shell of varying thicknesses and hardnesses. Dry fruits, such as peas and beans, grow in pods that either open down a seam (dehiscent), or stay closed (indehiscent), as in the case of peanuts and most cereal grains, such as wheat and barley.
Seeds have three parts: the embryonic plant, stored food, called endosperm, and a protective seed coat. As temperatures rise and moisture is absorbed through the sed coat, a primary root, called the radicle, will emerge, followed by the first stem, or hypocotyl. First leaves, or cotyledons often look very different from adult leaves.
Flowers exist solely to attract pollinators. Only angiosperms make flowers. Gymnosperms, such as conifers, ginkgo trees, and cycads make cones, or strobili. The colors, patterns, showy displays, and sweet aromas we associate with flowers are all in place to attract insects, bats, and birds. Flowers are supported by a stem called a peduncle. Small green leaf-like structure, called sepals, are often seen at the base of a flower. A collection of sepals is called a calyx. Individual petals may produce nectar or scent. All of the petals together are called the corolla. The combined corolla and calyx are called the perianth. The tip of a flower stalk, called the receptacle, contains the plant’s reproductive organs. Flowers can be male, female, or both, though not always at the same time. The female part, or pistil, consists of a pollen-receiving stigma, supportive style, and the ovary. [When you eat saffron, you are eating the style and stigma of an autumn crocus flower.] The male part, or stamen, consists of a pollen-producing anther and a supporting filament. Flowers are very useful in plant identification.
Genetic research and electron microscopes have brought plant anatomy to exciting new levels. Assumptions about kinship have been wrecked asunder and colorized scanning electron microscope (SEM) images can be breathtaking. Different types of plant cells gather together to create tissues. Those tissues come together to create the functional parts of a plant.
Ultimately, all those functional parts grow into delicious, nutritious foods that we can cultivate in our yards for decades. For me, feet up in the yard with a nice glass of wine beats standing in line at a grocery store any day!
What do wedges of citrus, hard walnut shells, the white bits inside a pomegranate, and the paper coating around avocado pits have in common?
They are all endocarps.
How can this be? How can structures so very different be the same part? Let’s find out by starting with some basic fruit facts.
The fruits and seeds we eat are plant ovaries. When a flower is pollinated and fertilized, three new structures form: seeds, pericarp, and placentae. Embryonic seeds attach to the placenta, and pericarp begins to grow, to feed and protect the embryonic seed, and to attract seed-spreading herbivores. There are three different types of pericarp tissue: exocarp (outer skin), mesocarp (flesh), and endocarp (inner layer). So, endocarp is the interior fruit that surrounds seeds. But what about all those differences?
Types of endocarp
Endocarp is generally not fruit in the way you would expect, unless you are talking about peppers or citrus. The fleshy parts of sweet peppers and chili peppers is the endocarp, as are those membranous wedges of fruity goodness found inside lemons, limes, and oranges. If you look inside an apple, the endocarp is the hard clear plate-shaped bits close to the seeds.
If you take a close look at a stone fruit, such as a nectarine or cherry, the endocarp is very hard and inedible. To us, it looks more like the shell of a nut. And guess what? The hard outer shell of walnuts, pecans, and almonds, that shell is the endocarp, even though, to us, it looks as though it is on the outside.
Confused? Read on!
Nuts about endocarp
When a nut develops on a tree, the exterior rarely looks like what you see in the grocery store. Many nut species have smooth or furry green exteriors (exocarp). That exocarp coats a hard, familiar shell. That shell is the endocarp of a nut.
Stamens are the male aspect of a flower.
Flowering plants, or angiosperms, have flowers that can be male, female, or both, though not usually at the same time.
The word stamen comes to us from the Latin word for ‘thread’. This is because the stamen is a threadlike stalk, called a filament, which has a pollen-producing anther on top. The stamen usually surrounds the female part, or pistil, though not always
Different plant families have different arrangements of pistils and stamens. For example:
When eating edible flowers, it is a good idea to remove the stamen and pistils and just eat the petals and other parts. The only exceptions are violas and Johnny-jump-ups. In these cases, the other parts add good flavor. Saffron threads are the dried [female] styles and stigmas of a specific crocus flower species, not the stamen.
Melons, zucchini and other squashes can easily be hand-pollinated by breaking off a pollen-carrying stamen and touching each of the flowers flowers with it.
Now you know.
Basil’s fragrant leaves make it a garden favorite, but there is a new disease on the horizon: basil downy mildew. And warm, moist conditions are all basil downy mildew needs to set up housekeeping on your basil plants.
First seen in Africa, in the 1930’s, basil downy mildew (Peronospora belbahrii) came to the U.S. in 2004 on infected seeds from Italy. By 2008, it had made its way to California and is now a global problem for everyone who enjoys basil and pesto.
Like other downy mildews, basil downy mildew is caused by tiny, algae-like microbes called oomycetes. Oomycetes parasitize vascular plants to complete their life cycle. They do this by collecting on the underside of leaves. From there, these tiny one-celled creatures send out threads that enter the leaf through the stoma and begin propagating. Since the oomycetes cannot pass beyond leaf veins, the damage from each infection is usually contained between leaf veins.
New spores are then released through the stoma, where they fall to soil, waiting to be splashed right back up by rain or irrigation water, or caught on the breeze for a ride to a new host plant. The party responsible for basil downy mildew travels on a variety of surfaces to reach your garden. In addition to water and wind, spores can be carried on garden tools, clothing, transplants, and infected seeds.
So how do you know if your basil plants are infected?
Symptoms of basil downy mildew
Unfortunately, the earliest sign of infection, yellowing leaves, looks a lot like nutritional deficiencies. If you see yellowing between the major leaf veins with dark blotchy areas, take a closer look on the underside of those leaves. If you see purple or gray powdery spores, it is probably basil downy mildew. Those spores are reproductive bodies and each infected leaf is a disease factory.
Once a plant is infected, it is too late. Harvest any healthy leaves and bury the plant under soil or in the compost pile to prevent spores from spreading. Generally speaking, these pathogens will not survive in compost or through winter temperatures. We hope. For now, the basil downy mildew pathogen is under California State quarantine, which means infected plants must be destroyed.
Preventing basil downy mildew
To avoid being part of the problem, be sure to buy only certified disease-free seeds and seedlings, place all new plants in quarantine, and monitor plants closely.
Good air circulation goes a long way toward keeping leaves dry. Dry leaves are not hospitable to this disease, so keep irrigation water at ground level. Skip the watering can. Instead, use a soaker hose or drip system that will prevent spores from splashing up onto the underside of leaves.
At the end of the growing season, cut basil plants off at ground level and compost them completely. Do not leave them in place to harbor disease. This helps break the disease triangle and reduces the chance of things starting up again each spring.
Some research is being done on the effectiveness of spraying basil plants with fixed copper as a preventative, but the results are not yet in.
If you think basil downy mildew has appeared in your garden, please notify your local County Extension Office or Department of Agriculture. You can even use the Basil Downy Mildew Reporting Page to add you contribution to science!
Exquisite nuts or toxic leaves, how much do you know about the cashew family?
Expensive, delicious, and nutritious, cashews (Anacardium occidentale) are treat that you just might be able to grow at home. Before you start planting, however, there is more to the cashew family than meets the eye.
Cashew fruits and nuts
In most cases, these trees, shrubs and vines have female and bisexual flowers while others have male and bisexual flowers. If you want to grow your own, you will probably need two or more plants, with one of each gender.
Did you know that those delicious cashew nuts are not really nuts at all? Instead, they are drupes, much like the pits found in stone fruits, such as almonds, cherries, and peaches. In the same way that those trees, fig trees, strawberries, and pineapples produce accessory fruits, cashew trees do, too. The only difference is that cashew nuts hang underneath their accessory fruits, known as cashew apples. Cashew apples are used to make sweet, astringent drinks and liquor.
If you start taking a cashew drupe apart, you will find that the seed coat is very thin and that there is little or no endosperm, also like a strawberry. [You can think of a seed using endosperm to grow the same way we would use a peanut butter sandwich, while accessory fruits are more like drinking juice - both cases provide nutrition, but in different ways.] Before you try this, be sure to don some rubber gloves. More on that in a minute.
Members of the cashew family
There are hundreds of members of the cashew or sumac family. Along with delicious cashews, the cashew family includes some favorite edibles, and a few you may not have heard of before:
Here, in North American, smooth sumac (Rhus glabra) and stag horn sumac (R. typhina) are used to make a drink called “sumac-ade”. The cashew family also includes mastic trees (Pistacia lentiscus) and varnish trees (Toxicodendron vernicifluum), which are the trees that give us varnish, lacquer, and useful oils. Natural varnish is made from tree resin.
Like many other families, there is heated debate about who belongs and who does not. Not too long ago, pistachio plants were brought into the cashew fold, but there are still discussions about this in scientific corners. Cashew family taxonomy includes dozens of genera, most of which are not edible. Watch out, though - some of them might try to hurt you!
Cashews - beware!
Did you know that raw cashews are poisonous? They are. They contain the same chemical found in poison ivy, poison oak, and poison sumac. That’s because they are all in the same family! The sap of all cashew family plants, called urushiol, is something to be reckoned with as it can be highly toxic. Just under the bark, these plants have resin canals filled with the stuff.
If that weren’t bad enough, the seed coat of cashew drupes contains a toxic oil that is acidic enough to burn your skin. If you are still interested in growing your own cashews, read on. If not, read on anyway! Who knows what you’ll learn?
How to grow cashews
Being native to tropical and subtropical places such as India, Thailand, Sri Lanka, and Papua New Guinea, cashew tree might be difficult to grow, depending on your Hardiness Zone. If you are determined, however, it can be done. Keep in mind, before you get started, that mature, full-sized cashew trees can grow to nearly 50 feet in height. Dwarf varieties are far more manageable at only 20 feet.
Cashew trees prefer loose, sandy soil with plenty of sun and excellent drainage. Do not try using grocery store seeds - they are not viable. You will need to get seeds from a reputable supplier. Viable seeds should be planted 4 inches deep and about 30 feet away from each other. These plants can handle temperatures as high as 122°F, but cold and damp will be the death of them. Heavy, soggy clay soil nearly always causes root rot in cashew trees. They don’t handle wind very well, either, so be sure to provide tree supports while trees are young and do not plant them in windy areas.
Keep your young tree properly irrigated and feed trees twice a year using a mix determined appropriate by your soil test results. Generally speaking, cashew trees use a lot of nitrogen, phosphorus, and zinc. After 3 or 4 years, you should be able to harvest your first crop of cashews. You will know your crop is ready to harvest when the cashew apple is either red or yellow and the drupe shell has turned grey.
Before you start nibbling, however, remember that the seed coat of cashew drupes contains a toxic oil. You will need to roast those nuts in a covered container at 375°F for 10 to 20 minutes. Traditionally, they are roasted covered in sand. Apparently, the toxins released as fumes during this process will ruin your cookie sheet or whatever lid you opted for, so choose accordingly and be sure to ventilate the area as you work. Since the oils within cashew shells is extremely acidic, it can burn your skin, so wear long sleeves and eye protection.
Next, shake the nuts in a sieve, if they were roasted in sand, and then wash them in soapy water to remove any residual toxins. Crack open your priceless cashews now and use a knife to remove the thin seed hull. Finally, saute your cashews in oil at 300°F for 5 minutes or so to neutralize any last bits of toxins.
Did you know that cashew shells have been used to make lubricants, paint, and military arms?
I didn’t either.
I think I’m beginning to understand why cashews are so expensive…
For anyone unlucky enough to have a chance meeting with poison ivy (Toxicodendron radicans), Pacific poison oak (T. pubescens), Atlantic poison oak (T. diversilobum), or poison sumac (T. vernix), you know all too well how those plants can make you devastatingly uncomfortable. Believe me, I speak from experience.
"Leaves of three, let it be; berries white, take flight; root hairs red, recoil"
[I made up that last bit.]
Sweet alyssum is a lovely, low maintenance flower that attracts butterflies, but it isn’t actually an Alyssum.
Not so long ago, when scientists first started using DNA to sort out plant species and plant families, a number of embarrassing relations and non-relations were discovered. This has lead to upheaval in the world of plant nomenclature. While this doesn’t generally affect us, as backyard gardeners, it can cause some confusion when it comes to plant names. So it is with sweet alyssum.
Native to the Mediterranean region, dainty sweet alyssum used to be counted among the Alyssum species. As such, it was known botanically as Alyssum maritima. [Isn't that a lovely name?] We now know that the global sweet alyssum plant is actually a Lobularia species, an equally pleasant name.. Again, this doesn’t make much of a difference for us, as home gardeners. What I was surprised to learn is that, in both cases, sweet alyssum is a member of the cabbage family, which means that it might attract the same pests and diseases as your cabbages, broccoli, and mustards. Before we start ripping out this tiny, durable flower, let’s see what it has to offer.
Sweet alyssum description
Each sweet alyssum plant grows up to 12” tall and wide. Stems are made up of several branches, each of which has many flower clusters. Most sweet alyssum flowers are white, but you may get an occasional blue, pink, or purple in the mix. These flowers have a honey sweet aroma that bees and other pollinators seem to love. As individual stems near the end of their life, a profusion of fruits, which are hairy elongated pods, like most other members of the cabbage family. Each pod contains two seeds. These seeds spread easily on the wind. And plants can thrive in a number of different locations.
How to grow sweet alyssum
Sweet alyssum somehow manages to grow in rocky outcrops, on sand dunes, between paving stones, and everywhere else seeds can get a toehold. This is good news. Unlike their perennial Alyssum cousins, sweet alyssum is an annual. If you have it growing already, you know that it readily self seeds.
Sweet alyssum is an excellent choice for softening paths, lining the edges of raised beds, or as a relatively maintenance-free ground cover. I say ‘relatively’ because sweet alyssum plants may get leggy and flop over near the end of their productive lives, leaving them to look somewhat less appealing. You can eliminate this look, and stimulate new flower growth, by occasionally giving plants a trim. I use my weedwacker.
Sweet alyssum pests and diseases
As far as cabbage family members go, sweet alyssum is rugged. It has very few problems. Diseases that may impact your sweet alyssum include botrytis blight (grey mold), clubroot, downy mildews, and root and crown rots, though I have never seen any of those diseases on my sweet alyssum while the same diseases have, at times, been present on nearby plants. Supposedly, the cyclamen mite and caterpillars of the diamondback moth feed on sweet alyssum. Again, I have not seen this in my garden. The only pest that I have seen hiding out, under the canopy of sweet alyssum blossoms is the dreaded Bagrada bug.
Rather than ripping out your sweet alyssum, just trim it back every once in a while and be sure to take a peek underneath its skirts every once in a while, with an eye for Bagrada bugs.
What do peaches and potatoes have in common? The green peach aphid.
Considered the world’s worst disease vector among garden plants, green peach aphids (Myzus persicae) love to feed on peach and potato leaves, along with dozens of other garden plants.
Green peach aphid description
Green peach aphids are generally found in colonies of winged and wingless adults and immature nymphs. Green potato aphids look a lot like potato aphids (Macrosiphum euphorbiae). While potato aphids can be seen throughout the plant, green peach aphids prefer hiding on the underside of leaves.
Damage caused by green peach aphids
Green peach aphids often overwinter in the egg stage on stone fruits, particularly on peach and peach hybrids, though apricot and plum are also favored. In spring, these eggs hatch and nymphs begin feeding on buds, flowers, and new stems. A few generations later, which only takes a month or so, winged adults move to summer feeding areas. It would probably be simpler to list the garden plants that do not attract green peach aphids, but you do need to know where to look for these pests.
Summer feeding can occur on artichoke, asparagus, beans, beets, broccoli, Brussels sprouts, cabbage, carrot, cauliflower, cantaloupe, celery, chili peppers, corn, cucumber, fennel, kale, kohlrabi, turnip, eggplant, lettuce, mustard, okra, parsley, parsnip, peas, peppers, potato, pumpkin, radish, spinach, squash, sunflowers, tomatoes, turnips, watercress, and watermelon.
Aphids prefer feeding on tender new growth. This leads to wilting, water-stress, and stunting. It also generates a lot of honeydew (sugary insect poop), which provides the perfect growth medium for sooty mold. Heavy aphid feeding can weaken a plant to the point of death. The bigger problem, as with nearly all aphid species, is that these pests carry diseases. Green peach aphids may infect plants with a variety of viral diseases, including:
If potato leafroll virus appears in your garden, it is a good idea to remove the infected plant, plus three other plants in every direction, to prevent green peach aphids from spreading the disease even further. This is yet another reason why it is so important to plant certified disease-free plants in the first place. These pests are often found in greenhouses, so placing new plants in quarantine can go a long way toward preventing an infestation. They can also travel on the wind, so it's a constant battle.
Green peach aphid management
The best way to control green peach aphids is to hit them in winter. This means removing overwintering sites, such as infested leaves, spent plant debris, and nearby weeds. Malva is a popular winter wonderland for aphids, so keep that weed away from your peach trees and potato plants. Bindweed, lambsquarters, penny cress, pigweed, sowthistle, tumbleweeds, white goosefoot, and rouge members of the nightshade family can also provide overwintering sites for this pest.
As spring and summer come around, however, you can attract and protect beneficial predators, such as lady bugs, lacewings, parasitic wasps, and syrphid flies, by providing fresh water, planting a variety of insectary plants, and avoiding the use of broad spectrum pesticides. Most chemicals designed to kill aphids cause more harm than help by disrupting the lifecycle of many natural predators. There is also a parasitic fungus (Entomophthora aphidis) that attacks aphids, but you can’t do anything about that one.
Early each June, in northern California, green peach aphids migrate into our gardens. You can prevent a full-blown infestation by monitoring plants on a weekly basis and using a damp rag or paper towel to wipe off colonies before they can really start propagating. A single female, hatched in spring, can reach sexual maturity in only 10 days, creating 20 generations in a single year. By the end of summer, this can result in billions of offspring.
Bacterial brown spot is a bacterial disease that causes brown spots on beans, lentils, and other legumes.
The bacterium responsible for bacterial brown spot is called Pseudomonas syringae pv. syringae. This bacteria is already found on the leaves of many different plants. Wind, rain, overhead watering, or coming into contact with infected seeds and plants can cause bacterial population explosions in snap beans, pole beans, peas, lima beans, and other legumes. Bacterial brown spot can also infect orchids, so be sure to wash your hands and sanitize your tools.
The pathogen enters through stoma and points of injury, usually when temperatures are below 85°F, and during the rainy season. Before long, symptoms will appear.
Bacterial brown spot symptoms
Bacterial brown spot is frequently confused with halo blight and common blight. In all three cases, small, water-soaked lesions appear on leaves. In common blight, those lesions have wide, lemon-colored borders, and they continue to grow. Halo blight lesions tend to stay small and they have prominent light green halos, hence the name. Bacterial brown spot lesions have narrow light green borders and the centers tend to dry out and look tattered. The spots may overlap, creating an even more tattered appearance. Pods infected with bacterial brown spot become distorted. Lesions are also seen on stems.
These lesions interfere with photosynthesis, weakening plants and reducing your crop. Rather than allowing infection to spread, it is better to remove infected plants and toss them in the trash.
Preventing bacterial brown spot
Start out with certified disease-free plants and seeds. If you buy plants, put them in quarantine until you are certain that they are healthy.
Overhead watering spreads bacterial brown spot infections, plus it provides the bacteria with needed moisture, so don’t do it. Use soaker hoses, drip lines, or simply hold your garden hose closer to the ground as you water.
At the end of the growing season, remove host plant debris and add it to the compost pile. Crop rotation and fixed copper sprays can also reduce the risk of bacterial brown spot.
Mottles are symptoms of viral disease. Mottles are irregularly colored, spotted, or blotched areas. These discolored areas are usually yellow. Simple, right? Well, those words also describe mosaic diseases, which are different from mottles. I think.
Note: Have you ever started something, thinking it would be simple, and come to find out that there is a lot more to it than you ever would have thought? Mottles are like that.
There are several families of viruses that cause mottle diseases in plants. They cause mosaic diseases, too. And each of these families causes dozens, maybe hundreds, of diseases. I had no idea. There are even sub-viral agents, which lack the genetic instructions needed for replication. Because of this, they use helper viruses to set up household in plant victims. I swear, the more I learn, the stranger the world gets.
There are countless plant diseases that present with mottles, including:
What I have learned is that mosaic patterns tend to be dark green on green, yellow on green, or gold on green, with either distinct or fuzzy borders, and in systematic patterns. Mosaic diseases may also appear with vein banding, stripes, streaks, and variegation.
Mottles, on the other hand… well, um, well, mottles can look exactly like mosaic diseases, but without the variegation, banding, or stripes. Rats! The only information I could find was that mottles can also appear on fruit, while mosaics tend to be seen only on leaves. I think. And then there are diseases like cucumber green mottle mosaic and soybean yellow mottle mosaic virus. Agh!!!
If you think the first photo looks exactly like this photo, you would be correct. Apparently, even the experts haven't sorted all this out yet, so don't feel as though you should understand it all. I certainly don't!
Maybe mottles and mosaics are the same thing after all. If you know the answer, please share it with the rest of us in the comments.
Bottom line, if you see uncharacteristic coloration on leaves or fruit, you need to take a closer look and consider what might be causing it before a full blown infection wipes out your crop.
Armillaria root rot is a soil borne that attacks the roots and trunks of many fruit and nut trees. It is also the largest living fungi in the world.
In Oregon’s Malheur National Forest, there is a mushroom colony that covers 2.200 acres. That colony is believed to be a single entity, all growing from the same network of fungal mycelium.
By itself, that's impressive. In your tree, it's a deadly fungal disease.
Trees vulnerable to Armillaria root rot
Also known as honey fungus, shoestring fungus, or oak root fungus, Armillaria root rot (Armillaria mellea) is a deadly disease that infects avocado, cherimoya, cherry, chestnuts, conifers, kiwifruit, kumquat, lemons and other citrus, pomegranate, stone pine, and walnuts, along with the mighty oak. If that weren’t bad enough, trees weakened by Armillaria root rot become more susceptible to serious pests, such as Pacific flathead borers.
Armillaria root rot symptoms
Everything starts out looking fine. Your tree is growing nicely and you suspect nothing. Suddenly, you notice downward cupping leaves, chlorosis (yellowing), dieback of upper limbs, and leaf drop. You may also see a variety of mushrooms growing nearby.
Your tree is dying. Young trees die quickly, while older trees make take longer, but the end result is nearly always the same.
Armillaria root rot diagnosis
If your tree shows the above mentioned symptoms, take a closer look at the base of your tree. You may be able to see fan-shaped fungal growth rising up the trunk from the soil level. Use a sharp knife and cut away a section of bark at the base of the tree, so you can see the cambium layer. If you see white fungal threads (mycelia) and can smell a strong mushroom odor, your tree is in serious trouble. If you see reddish brown streaks or patches, or water-soaked areas, the infection is more likely to be Phytophthora root and crown rot, rather than Armillaria, though that isn't any better news for your tree.
If you have easy access to the tree’s roots, cut one open. Infected roots are darker than normal and have a cottony center. You may also see black rhizomorphs, called ‘shoestrings’, on the surface of infected roots.
How Armillaria spreads
As a soil borne disease, Armillaria mycelia can remain viable in the soil for many years. It isn’t until a healthy root comes into contact with infected wood, roots, stumps, or other wood fragments. Then, the fungus enters the healthy tree and begins to populate the cambium layer, eventually killing the tree. Infected nursery stock can also carry this disease, so always quarantine new plants.
Preventing Armillaria root rot
Good drainage, sunburn protection, and proper (not excessive) irrigation can all help protect your trees against Armillaria root rot. Once infection occurs, the tree should be completely removed and the area should only be planted with crops that are not vulnerable to Alternaria root rot.
Dark brown spots on your tomatoes? It’s probably early blight.
Cool spring temperatures and too much rain or other moisture creates the perfect storm for this fungal disease. The early blight fungus (Alternaria solani) is a disease of the nightshade family, which means your potatoes, eggplants, bell peppers, and chili peppers are equally susceptible, as are other plants in the nightshade family, such as petunias and blue potato bushes. If similar lesions are seen later in the season, it is more likely to be late blight, also known as the dreaded potato blight.
Early blight was once a disease found only on the east side of the Rocky Mountains. Sadly, that is no longer the case. The early blight pathogen is now found everywhere host plants have been grown and can result in up to 30% of your potatoes and 79% of your tomato crop ending up in the trash bin.
Early blight symptoms
Small black or brown spots, usually 1/4 to 1/2 inch in diameter, may appear on fruit, leaves, and stems. These spots may have a concentric rings pattern, or bullseye. Fruit spots are dry, sunken areas, most commonly seen near the calyx end of the fruit. [That’s the flower end, as opposed to the stem end.] Spots on leaves feel leathery. Symptoms are seen on older leaves first. Stem lesions do not have the same circular, bullseye pattern.
In some cases, this pathogen can cause collar rot and damping off, which usually kills seedlings. As the disease progresses, leaf loss can significantly reduce fruit production. Honestly, the fruit that is produced doesn’t look particularly appetizing. Infected potatoes either rot in the ground or in storage.
Early blight lifecycle
Fungal spores overwinter in the soil and on infected fruit and plant debris. Rain and overhead irrigation splash spores onto plants, where they begin reproducing. To reduce the chance of early blight in your garden:
Fixed copper or sulfur sprays can provide fungicidal benefits in heavy infestations. Also, healthy plants are less likely to become infected, so feed and water your plants properly, give them enough space to reach full size, and help them avoid physical injuries, which provide entry points for early blight fungal spores.
Are your strawberry plants looking pitiful? Do they fail to produce big, luscious fruits? It may be virus decline. [And those berries are not really berries, they are accessory fruits, but I digress.]
Virus decline is a combination of multiple viral infections that leave strawberry plants looking like they’ve missed too many meals.
Causes of virus decline
Virus decline is a combination of viruses: Strawberry pallidosis associated virus (SPaV) or Beet pseudo yellows virus (BPYV), both which are spread by whiteflies, combined with any one of several other viruses commonly spread by aphids. Because virus decline is a combination of infections, plants may look fine one day, even though they’ve already been infected by SPaV or BPYV, and then look bad a few days later, having become infected with another of the relevant viruses. These aphid-borne viruses include:
Strawberry latent ringspot and Fragaria chiloensis latent viruses may also play a role. Research is currently underway.
Virus decline symtoms
Plants infected with virus decline are often stunted, sometimes severely. Leaves turn purple or red, though new growth that forms near the center of the plant may remain green. There is little or no fruit production, and the roots are brittle and reduced. These plants will never be productive.
Control of virus decline
You cannot know for sure if your strawberry plants have virus decline without sending a sample in for lab testing (which your County Agriculture Office may offer for free). but declining plants are best removed and replaced, preferably in a new location.
One way you can reduce the likelihood of virus decline occurring in your strawberry patch is to keep other plants that might host these viruses at a safe distance. The SPaV virus favors strawberries and its cousins, and a few weeds, such as nettle, creeping sibbaldia, mock strawberry, sharp leaf groundcherry, and cheeseweed. BPYV, however, has a taste for your melons, squashes, lettuces, cucumbers, endive, and spinach, along with marigolds, zinnia, dandelions, and cheeseweed.
To reduce the possibility of virus decline in your strawberries:
These steps are no guarantee, but they will significantly reduce the chance of your plants becoming infected.
Two-spotted spider mites can kill off many of your garden plants as temperatures rise and humidity drops. Before a hot, dry summer kicks in, it’s a good idea to know what to look for.
Two-spotted spider mites (Tetranychus urticae) can become a serious threat to your citrus and other fruit trees, most vegetables, and many ornamentals, such as marigolds, roses, and salvia. Beans, blackberries, blueberries, cucumber, eggplant, lettuce, peas, squash, strawberries, and tomatoes are all favorite foods of the two-spotted spider mite.
Two-spotted spider mite description
As arachnids, all mites have two body segments and eight legs. Two-spotted spider mite eggs are round to spherical, but very difficult to see. Instead, you may see the webbing used to protect those eggs. Colorless larvae, which start out with only six legs, go through two developmental stages to reach greenish-yellow, eight-legged adulthood. This transformation can occur in as little as 5 days, and females can lay 120 eggs in their lifetime, so populations can rapidly explode.
An interesting note, unfertilized eggs hatch into males, while fertilized eggs hatch as females. This is called arrhenotoky.
Males are smaller and have narrower bodies and are more active than females. These close cousins to red mites are greenish-yellow to brown, with two dark spots, and they even have a red winter phase, but you probably won’t be able to see them without a hand lens. [Those dark spots are accumulated body wastes, so they are not always visible.] At only 1/50” long, two-spotted spider mites are easier to find by looking at the damage they cause.
Damage caused by two-spotted spider mites
As sap-sucking pests, similar to citrus mealybugs and citrus bud mites, these mites pierce plant cells and remove the contents. Hidden from view by feeding on the underside of leaves, they often go unnoticed until the damage becomes obvious. Mite feeding causes stippling and bleaching. These damaged areas increase, causing bronzing and early leaf drop. If you look at the underside of these leaves, you will often see the cast-off exoskeletons of mites. You may also see extensive webbing over buds, stems and flowers. Extensive feeding can cause stunting and even plant death.
How to manage two-spotted spider mites
Since two-spotted spider mites feed on such a wide range of plants, they are difficult to control. Mites favor feeding on stressed plants, so proper feeding and irrigation can help your plants seem less appealing to these pests. In addition, you can use these tips to reduce problems caused by two-spotted spider mites:
Predatory mites, such as Phytoseiulus persimilis, ladybugs, minute pirate bugs, and lacewings are all beneficial insects that feed on two-spotted spider mites, so keep you yard hospitable to these helpful predators. Mites are developing resistance to most chemical pesticides, but insecticidal soaps are effective against mites, with horticultural oils (not dormant oils) coming in a close second. These treatments are only affective against the mites that come into contact with it, so repeat treatments are often necessary.
The ashy grey lady beetle is both stylish and deadly.
We’ve all seen the red domed lady bugs of popular culture, with their shiny black dots, but what about the black lady beetles with red dots?
There are only four types of black lady beetles with red spots. The twicestabbed lady beetle (Chilocorus orbus), Axion plagiatum, Chilocorus kuwanae, and the ashy grey (Olla v-nigrum). Unlike other lady beetles, however, the ashy grey comes in two forms: dark and tan, which can be changed at will!
Ashy grey lady beetle description
Ashy grey lady beetles are sometimes ashy grey or tan, with black spots. At other times, they are black with red spots. Before they reach their domed adulthood, ashy grey lady beetles look more like tiny alligators with yellow spots.
And before that, as pupae, they look like little orangish-yellow nubs. As eggs, they look like clusters of yellow, usually found on the underside of leaves, close to prey.
Ashy grey lady beetle prey
While ashy grey lady beetles do feed on the eggs of butterflies and moths, the lion’s share of their diet consists of aphids and psyllids. Since aphids and psyllids are both disease-carrying, plant-sucking pests, we can use as many lady beetles as we can get in the garden.
To attract ashy grey lady beetles and other beneficial insects to your yard, avoid using broad spectrum pesticides, provide fresh, clean water, and plant a variety of insectary plants, such as dill, lavender, chives, mint, tansy, and yarrow, just to name a few.
How many different types of lady beetles are in your garden?
You can grow a surprising amount of food in your own yard. Ask me how!