Gumming does not mean your tree has lost its dentures. Instead, it is responding to injury.
Unlike people and animals, plants do not have an active immune system. Instead, injured or infected areas are walled off to prevent further injury or the spread of infection or infestation. Gumming refers to the way a specialized sap, or botanical gum, oozes out of an injury site or canker to provide protection.
Gumming is particularly common among stone fruits, such as nectarine and almond, though is can also be seen on mango, citrus, and eucalyptus.
Causes of gumming
Environmental stress, mechanical injury, insect attacks, and disease can all trigger a tree to start gumming. This creates a protective barrier, as well as tries to push any invaders out. You can use specific details surrounding gummosis to identify the problem.
For example, gummosis caused by insect infestation or mechanical injury will often exhibit bits of bark or sawdust mixed in with the gum. Look for other damage around the gumming site: Do leaves look sick or chewed upon? Has the bark’s integrity been breached? Do you see discoloration under the bark near the gumming?
How to manage gumming
You can help your fruit and nut trees stay healthy by avoiding mechanical injuries, and monitoring for pests and diseases on a regular basis, along with proper feeding and irrigation. If you suspect disease, scrape some of the bark away from the area surrounding the gum. If you see discoloration or streaking, it is probably a disease that needs further attention. In many cases, diseases can be halted by removing affected branches below the infected area, just be sure to sanitize cutting tools between each cut.
If the gum emerges from circular holes and contains insect larvae, the tree is taking care of the problem itself, though further monitoring is a good idea.
Before you swat that tiny wasp away, take a closer look.
It may be one of the Good Guys.
These tiny wasps serve us well in the garden, so avoid using any broad spectrum pesticides and let nature take its course.
Who knew apples could get the measles?
Unlike the human variety, which is caused by a virus, apple measles is a symptom of manganese toxicity.
Manganese is a micronutrient used by plants to make chlorophyll. It is an important component of chloroplasts. Manganese is used by all living things as an antioxidant, to counteract the toxic effects of oxygen. Manganese can also be phytotoxic, which means it can be poisonous to plants.
Symptoms of apple measles
The first sign of apple measles is tiny red pustules on new twigs. If you look closely, you can see that the tissue in the center of each pustule is dead. Take a look on the inside of the twig and you will see that the lesion spreads, under the bark, into the cortex or the phloem tissue. If you take a cross-section of the twig, you will see brown streaks or flecks. As the affected twig matures, the bark thickens, cracks, and sloughs off, leaving flakey cankers. This flaking off of bark can last for several years.
Treating apple measles
Since apple measles is a symptom of too much manganese in the soil, you need to alter the soil chemistry to help your apple tree. Apple measles occurs most commonly in acidic soil, so increasing the soil pH with lime or other alkaline soil amendment will help reduce future damage.
Unfortunately, it is very difficult for trees to recover from apple measles, so get your soil tested every 3 to 5 years, so you know what they are dealing with - before the damage is done.
Apple trees produce fruit on spurs. Spurs are stubby stems that form along longer stems. Bourse shoots are vegetative growths that do not produce fruit, but they are an important part of fruit production, and we are still not entirely sure why. [Being cousin to apples, all of this information is relevant to pears, as well.]
Apple tree anatomy
Before we learn about bourse shoots, we need a quick review of apple tree anatomy. Apple trees tend to grow long stems. If those stems grow upright, your apple tree is of the alternate bearing variety. If those stems tend to hang downward, your apple tree is a regular bearing type.
[Many commercial apple growers spray chemicals on apple trees to cause artificial fruit drop on heavy production years to encourage a bigger return bloom the following year. Return bloom refers to the blossoms that appear after the current crop is under way. This evens out annual fruit production, maintaining supply and keeping prices consistent.]
One study, published in the Journal of Horticultural Science, explains how the removal of too many bourse shoots significantly reduces return bloom.
Along those stems, whichever way they happen to grow, are little stubby growths called spurs. The majority of an apple crop is found on the ends of spurs. Each spur can produce fruit for 8 to 10 years, or more. Those spurs grow out of swollen areas, called bourses.
Not to be confused with bourses, bourse shoots are vegetative stems that emerge just below flower buds. In some cases, new spurs can suddenly shift their growth to become a bourse shoot instead of a spur. These bourse shoots feature a whorl of leaves. In the center of those leaves, a bud may form later in the season, but they tend to be less productive than spurs. This transition from vegetative growth to floral growth, called floral inflation, is believed to be caused by an abundance of sunlight and sugar. Other causes of floral inflation include fruit thinning, summer pruning, and bending upright shoots to a more horizontal orientation.
A common term among apple growers is bourse-over-bourse. This refers to bourse shoots emerging from existing bourse shoots, in a waterfall style growth pattern. Too many bourse shoots on one stem can lead to spur extinction. Spur extinction describes the point where a spur is no longer productive. If you see multiple bourse shoots on a stem, you can improve fruit production by pruning back to the innermost bourse shoot.
Pruning apple trees
Standard dormant season apple pruning involves removing all dead, diseased, or rubbing branches, as well as 15 to 20% of the previous year’s growth. Next, you should remove excessive bourse-over-bourse growth, and bourse shoots that are especially long, as they tend to be less productive than shorter or medium-length bourse shoots. Don’t remove too much, however. One study, published in the Journal of Horticultural Science, explains how the removal of too many bourse shoots significantly reduces return bloom [next year’s crop].
Bottom line: next year’s apple (or pear) crop is highly dependent on the number of leaves produced during the current year. If your apple tree has more bourse shoots, it is more likely to have more leaves, ergo, more fruit. But this is only true if those bourse shoots are spread evenly throughout the tree.
Many sap-sucking pests are attracted to the color yellow, and you can use that to your plants’ advantage.
Much the way sticky barriers prevent crawling insects from climbing up into fruit and nut trees, yellow sticky sheets attract and trap many flying insects that might carry death and disease to your garden plants.
Unlike pesticides and other chemicals, insects cannot develop a resistance to stickiness - not any time soon, any way! Plus, sticky sheets do not cause harm to people or pets. The worst that can happen is they will stick to you temporarily. When an insect lands on the sticky surface, it means death. They cannot escape, reproduce, feed, or spread disease. They are done, and all you have to do is toss them in the trash.
Yellow sticky sheets can capture a wide variety of pests, including:
Yellow sticky sheets are often used in tandem with pheromone traps. The pheromones lure the insects closer and then the yellow sticky sheet makes them unable to fly away.
Whether you use a pheromone trap in conjunction with yellow sticky sheets or not, you can use the sticky sheets to monitor for pest populations in and around specific plants or beds.
Personally, I hang them in my citrus trees in early spring to significantly reduce leaf miner damage, and to help me know what else I happen to be up against at any given time.
The best news about yellow sticky sheets? They’re cheap. And if you are having problems with indoors pests, you can always cut the sticky paper into a decorative shape and put it to work for your container plants!
Every year, there are garden favorites that we plant religiously. Just as consistently, the same pests come, causing damage and carrying disease. What if there was a way to lure those pests away from your garden faves?
There is. It’s called trap cropping.
Trap cropping refers to the purposeful planting of crops known to attract or repel specific pests within and around the crops you are trying to protect. This distraction reduces the damage done by pests. In some cases, the attractant trap crop can interfere with the pest’s lifecycle, or kill it outright. In other cases, as pests start feeding on the trap crop, you harvest it, breaking the lifecycle of specific pests.
Trap cropping is a form of companion planting (better known as intercropping). While mint, garlic, nasturtium, and fennel have often been touted as cure-alls for many pest problems, the science behind trap cropping is still relatively new and I was unable to find enough research geared specifically toward those plants.
Fear not, however, as there is plenty of good information you can use to protect your garden plants!
How trap cropping works
Trap crops distract pests away from food crops. By providing a rich food source for these pests, they are less likely to damage your food crops. Also, heavy pest infestations attract beneficial predators, such as lacewings and lady beetles. Once an infestation occurs, the trap crop can be fed to your chickens, tilled under, or composted. In commercial fields, pests attracted to trap crops are killed off with pesticides or vacuumed off the plants and destroyed.
Types of trap cropping
There are several types of trap cropping:
Very often, trap cropping methods are used in combination, improving their effectiveness. These methods reduce the need for chemical pesticides, while increasing biodiversity.
Which crops have the biggest pest problems in your garden? And how can you use trap cropping to protect them? Let us know in the Comments!
Kumquats are members of the rue, or citrus family.
Native to south Asia, kumquats have been cultivated since the 12th century. Unlike oranges, or their giant cousins the grapefruit, kumquats are closer in size to olives. These somewhat tart fruits can be eaten whole, candied, chopped into a relish, fermented into a liquor, or cooked into a delicious marmalade.. These somewhat tart fruits can be eaten whole, candied, chopped into a relish, fermented into a liquor, or cooked into a delicious marmalade.
Kumquats are small, cold-hardy citrus trees. They grow slowly and can reach 8 to 14 feet in height. Glossy evergreen leaves provide excellent color and shade. Fragrant white flowers appear each year, but watch out for thorns. Similar to many other citrus trees, kumquat trees protect their fruit with sharp thorns. Each tree can produce hundreds or thousands of fruits every year.
Types of kumquats
Scientists are still sorting out kumquat classification, arguing over whether different types of kumquats are cultivars or species, but we can all agree that there are round kumquats (Citrus japonica), oval kumquats (Citrus margarita), and bell-shaped kumquats (Citrus obovata). There is also a variegated kumquat that features more fruit, less peel, and no thorns. All kumquats are self-pollinating, so you only need one tree.
Unlike oranges, kumquats can tolerate temperatures as low as 19°F, right along with scorching hot summers, making them an excellent choice in San Jose, California. Before you try planting a kumquat tree from seed, you need to know that that generally doesn’t work out well. Instead, kumquats are usually grown from cuttings, layering, or other vegetative propagation method.
Kumquats can be grown in containers. Container grown kumquats can grow to 6 feet and produce fruit, if they are fertilized regularly.
Kumquat pests and diseases
Asian citrus psyllid is the most serious threat to citrus trees, as they can carry huanglongbing, a fatal disease. The diaprepes root weevil may also become a problem. Leaf miners, aphids, scale insects, and whiteflies are far more likely. Citrus diseases, such as armillaria root rot, alternaria rot, anthracnose, brown rot, citrus blast, exocortis, and phytophthora root rot may occur. Kumquats tend to be resistant to citrus canker and most citrus trees thrive in the Bay Area.
Consider adding kumquats to your foodscape this year for a lifetime of fragrance, color, and Vitamin C!
Plant a seed at the proper depth and it thrives. Plant it at the wrong depth and it dies. So, how is a gardener to know how deep to plant each seed?
The general rule of thumb for seed planting depth is to use twice the seed width or diameter. This means a seed that is 1/8” wide should be planted 1/4” deep. Too often, seed packets rely on a standard 1/4” or 1/2” planting depth, which is not always in a seed’s best interest.
A seed’s life
Once a seed reaches maturity, it is protected by a hard outer shell called its seed coat. This layer allows the seed to roll, float, fly, or pass through a digestive system unscathed and ready to germinate. Only when heat, light, and moisture levels reach the right combination can the seed coat allow moisture in, which triggers the growth of the embryo within. Hopefully, the seed is at the proper depth to grow into a healthy plant.
Planting seeds too deeply
Seeds planted too deeply are less likely to germinate or sprout. Even if they do get that far, those seedlings have to work harder to reach the soil surface. This uses up valuable energy resources that should have been available for producing leaves and stems. It also reduces their growing season.
The very tiniest seeds should simply be sprinkled on the soil surface and only dusted with a covering of soil or vermiculite. And a few seeds, such as lettuce and dill, actually need light to germinate, so they should not be covered at all.
Planting seeds too shallowly
At the other end of the planting depth spectrum, seeds planted too shallowly end up with roots too close to the surface, causing them to wither and die. Even if they don’t die, shallow roots are less able to take up water and nutrients or to anchor plants in the soil. Seeds planted too shallowly are more susceptible to temperature and moisture level changes. These plants are also more likely to bolt, rather than producing a crop.
Seed planting depth also depends on soil structure. Seeds planted in rich, loose loam or sandy soil can tolerate deeper planting than seeds planted in heavy, compaction-prone clay.
Crops by seed depth
Here is a list of some of the more popular garden plants and their proper planting depths:
Tools, such as a dibble, can help ensure that seeds are planted at the proper depth.
Finally, do not press down on the soil once a seed is in place. This compacts the soil. Instead, the act of watering will tuck your seeds in nicely while still giving them a chance to grow and thrive.
You cannot see it, smell it, or taste it, but glomalin is the glue that holds soil together and the path by which nutrients move from beneficial fungi to plants.
When most of us think of fungi, we usually think of mushrooms or disease. Mycorrhizal fungi are an entirely different critter. These beneficial fungi live in soil, and in and around plant roots. They are responsible for helping over 70% of the Earth’s plants get the nutrients they need from the soil. They do this with glomalin. Glomalin is found on the tiny hairs, or hyphae, of mycorrhizal fungi. This coating helps the fungi to retain water and nutrients as they interact with local plant root systems.
Soil is made up of 45% minerals, 1-5% organic matter, 25% water, and 25% air, on average. Soil structure tells us the size of the mineral particles, which can be sand, loam, or clay. Air and water are found in tiny spaces, called macropores and micropores. The chunks of organic matter and minerals are called soil aggregates. Those aggregates are held together with glomalin. Soil aggregates improve water infiltration, drainage, nutrient cycling, root penetration, and water retention near roots. They also help counteract soil compaction.
What is glomalin?
Glomalin is a tough, resilient glycoprotein that contains significant levels of iron. It does not dissolve in water and it is resistant to decay. Also known as glomalin-related soil proteins (GRSP), glomalin stores carbon and nitrogen, and binds mineral particles together, coating them with the same protective barrier used to protect the fungi. It is now believed that up to 30% of the carbon sequestered in undisturbed soil is held specifically by the glomalin. This is one of the reasons behind no-dig gardening, in that it reduces the negative impact on the fungi responsible for creating glomalin and helping soil hold onto that carbon.
How does glomalin improve soil quality?
Glomalin was discovered in 1996 by Sara F. Wright, a USDA Agricultural Research Service scientist. She discovered that soils depleted of mycorrhizae and their glomalin, whether through exploitation, solarization, or fungicide use, had significantly reduced crop sizes.
Glomalin helps hold organic matter in place, improving soil aggregate stability. Soil aggregate stability is a measure of the combined physical, chemical, and biological properties of a soil sample, as well as its ability to resist degradation and erosion. Without glomalin, every drop of rain and every gust of wind would grind and disperse soil in a global Dust Bowl.
Glomalin is also what gives soil its brown color. Removing glomalin from soil leaves it a grey, rocky color.
So, what’s glomalin to you?
Recognizing the importance of mycorrhizal fungi and glomalin to soil health, you can improve plant and soil health with these tips:
By keeping your soil healthy, the natural processes needed by your plants to acquire nutrients and fight disease can continue.
Zebra chip may sound like a fun new black-and-white striped snack, but it’s not.
Zebra chip is a bacterial disease that attacks potatoes.
Like most bacteria, Candidatus Liberibacter solanacearum doesn’t move around very well on its own. Instead, it lives in the gut of potato psyllids. Potato psyllids are tiny, sap-sucking pests. As they feed, the bacteria move from the insect to the plant, infecting the vascular tissue in both the plant and its tubers.
Symptoms of zebra chip
There are no aboveground symptoms of zebra chip, but potato psyllid feeding causes foliage to turn yellow or purple. It can also cause pink or red discoloration of leaves.
The real symptoms are visible only after you cut into a tuber. The zebra chip bacteria cause potatoes to store sugar, rather than starch. That might sound like a great idea for a new dessert food, but the presence of sugars cause vascular tissue to turn into ugly brown lines. When cooked, these brown lines turn black, hence the name. This condition also reduces crop size by 20 to 50%. Healthy appearing potatoes from plants affected by zebra chip are more likely to sprout while in storage. Seed pieces taken from infected plants either do not sprout at all, or they produce weak, infected plants.
Controlling zebra chip
Since zebra chip is carried in by potato psyllids, that’s where you must work to break this disease triangle. Potato psyllids can be trapped with yellow sticky sheets and spinosad can be used to reduce potato psyllid populations. These treatments won’t get rid of all the psyllids, but they will help. Be sure to inspect potato, bean, and pepper plants regularly for signs of psyllids.
In commercially grown potato fields, where potato psyllids have been identified, a type of systemic neonicotinoid neurotoxin, called imidacloprid, is applied. [While not yet noted in California, resistance to imidacloprid has been documented in Texas.]
Zebra chips might sound like a fun new brand of potato chips, but what they really mean is you need to be on the lookout for potato psyllids as you work and play in the garden.
In the short days of winter, many of your fruit trees look as though they aren’t doing much of anything. Other than collecting chill hours and working to stay alive, that would be mostly true. As the days begin to lengthen, leaf and flower buds start to swell. But, sometimes, those swellings are something else entirely.
Also known as the almond and plum bud gall mite (Acalitus phloecoptes), this pest is native to Europe and the Middle East. As of January 2019, it made its way to California, threatening tens of thousands of plum, pluot, almond, apricot, and many other fruit and nut trees.
What are plum bud gall mites?
Plum bud gall mites are a type of eriophyid mite. Eriophyid mites are a family of microscopic plant parasites. These pests enter stems and buds through lenticels and injury points, and then overwinter under the bark. Very little information is available about this new pest, but knowing what to look for can help you to stop it from spreading.
Plum bud gall mite identification
In late winter, galls begin to form around these tiny invaders. By spring, adults emerge from their protective galls. At 1/100th of an inch in length, these mites are too tiny to see with the naked eye. If you have a 20x hand lens, you may be able to see them, if you look very closely. They can be a translucent yellow, pink, white, or purple, with two pairs of legs up near the head. You are more likely to see galls on new shoots and fruit spurs that plants produce in response to these invaders. Galls are warty, bumpy growths that don’t look like normal tissue.
Controlling plum bud gall mites
Treating your trees with wettable sulfur in March or April, when plum bud gall mites first start to emerge from their protective galls, has been effective in controlling these pests in other regions. Treatments may need to be repeated, depending on the level of infestation. Note that apricot leaves are very sensitive to sulfur, so you can only treat apricot trees with sulfur before leaves emerge. Because these particular eriophyid mites are new to the region, we do not yet know what sort of an impact native predatory insects will have on controlling plum bud gall mite populations.
If you happen to see this new pest on your trees, please contact your County Extension Office right away.
Each spring, pollen grains are normally moved from flower to flower by honey bees, beetles, butterflies and moths, and wind. When the pollen arrives at another flower, fertilization can occur and fruit can grow. Except, sometimes, the pollen needs a little help. That’s where hand pollination comes in.
Plants being grown indoors, or in areas without enough bees and other pollinators, cannot set fruit without mechanical pollination. Some crops, such as cucumber, melon, pumpkin and other squash, can be coaxed into producing far more fruit if hand pollination its used, due to the timing issues related to male and female flowers occurring at different times.
If you grow plants indoors, you will need to pollinate the flowers by hand to get fruit. Container plants that are at a distance from their fellows will also benefit from hand pollination. Loquats, kiwifruit, and mangos, in particular, often require hand pollination. [Due to heavy pesticide use in China, the lion's share of all their fruit crops are now pollinated by hand.]
Hand-pollination is not difficult, but it is tedious. To better understand how hand pollination works, let’s have a quick review of flower anatomy and the pollination process.
For a more detailed description, I urge you to read my posts on flowers and pollination. In the most basic terms, flowers can be male, female, or both, but not necessarily at the same time. Male flowers have a stamen and female flowers have a pistil. The stamen consists of a pollen-producing anther at the end of a filament. Pollen tends to be yellow and sticky. The female pistil, also known as a carpel, is usually found in the center of a flower and it consists of the sticky stigma, which captures pollen, the style, a tube that leads to the ovary, and the ovary itself.
As insects move around, collecting nectar and pollen for themselves, sticky pollen becomes attached to their legs and is carried from flower to flower. The pollen is captured by the stigma, enters the style, and moves toward the ovary, where fertilization occurs. If there are not enough pollinators, the pollen doesn’t get moved and we have no fruit. Unless you hand pollinate. By hand pollinating, you become the mechanism by which pollen is moved from the stamen of the male flower to the pistil of the female flower.
How to hand pollinate
There are two basic methods of hand pollination: removal of the anther, or transferring just the pollen. In most plants from the cucurbit family, the male anther is large and obvious. Without handling the part covered with pollen, simply snip off the anther, cut off or roll back the flower petals, and gently roll it around on the female pistil.
On plants with smaller flowers, such as cucumber, tomatoes, and melons, you can use a small, natural bristle painter’s brush or a cotton swab to transfer pollen from one plant to the other.
Timing is important
Male flowers tend to emerge before female flowers. Also, most flowers are only receptive to pollen for one day. Transfer pollen to freshly opened flowers, preferably in the morning. Do this every day until fruit starts to form.
Concerns about cross-pollination
This comes up every year. People worry that all members of a group, such as the cucurbits, can cross-pollinate. They can’t. Melons, squashes, and cucumbers are too different from one another to pollinate each other. That being said, varieties within a species, such as white pumpkins, Jack O’ Lantern pumpkins, and Atlantic Giant pumpkins can cross-pollinate.
Even if you have bees in your garden, you may want to try hand pollinating. Research has shown that manually applying pollen to female flowers results in larger fruit that is more likely to reach maturity. Also, the seeds within that fruit germinate faster and produce larger seedlings. This is called the xenia effect.
Did you know that researchers at Harvard are creating miniature flying robots, called RoboBees, to be used as pollinators?
Now you know.
Throughout human history, early spring has always been a time for eating fresh new greens. Slightly bitter, rich in iron and other important nutrients, they remind us that winter will not last forever.
Patience dock growth
Patience dock plants start out as broad leaves growing close to the ground. This is the part you want to eat. Next, a single stem emerges and is quickly covered with tiny flowers. Those flowers become pollinated and fertilized to produce triangular seeds, similar to rhubarb seeds. Seed heads hold large numbers of seeds, which darken to a lovely bronze color.
How to grow patience dock
Seeds are generally planted in late spring, slightly less than 1/2 an inch deep, in locations that receive lots of sunlight. Plants should be thinned or transplanted to provide at least 8 inches of space between plants. Lucky for those of us in the Bay Area, patience dock thrives in heavy clay soil. Young plants will require frequent watering, but mature plants require far less. If grown in a container, patience dock plants should be repotted each year with fresh potting soil, or mulched regularly with aged compost. Once established, plants are highly resistant to frost damage. You can divide mature plants every 3 to 4 years, in spring, to generate new plants.
Patience dock will flower throughout most of the summer, producing seeds enjoyed by local birds. Please note, this plant can become invasive because of all those seeds. To prevent this from happening, simply snip off the flowers and take them indoors and put them in a vase for your visual pleasure.
Patience dock pests and diseases
Slugs and snails, aphids, and the sorrel maggot are the most common pests, and I couldn’t find any mention of diseases, so this is a relatively trouble free plant.
“Go, Navy! Beat Army!”
No, wait. Sorry, that’s not what I meant.
Beet armyworms are insidious little creatures that may be burrowing into your young beets as you read.
Originally from Southeast Asia, beet armyworms were first seen in the U.S. in 1876. Today, they are considered major pests of many agricultural crops in areas without freezing winters. Like other armyworms, beet armyworms (Spodoptera exigua) are the larval form of a moth. In this case, it is a moth that flies around, laying eggs on some of your favorite garden plants.
While it might be easier to list the plants not susceptible to beet armyworms, you need to know where to look for these pests. In addition to beets, the list of potential beet armyworm hosts includes beans, celery, cilantro, citrus, cole crops, cucurbits, lettuces, parsley, peppers, strawberries, and tomatoes. Beet armyworms also attack alfalfa and cotton.
Beet armyworm lifecycle
Female moths lay pale, pinkish or greenish striated eggs in clusters of more than 100 eggs, often on the upper sides of leaves. These clusters look fuzzy, due to hairlike scales left behind by the moth. After they hatch, larvae begin feeding on nearby leaves, slowly dispersing throughout the plant. As larvae get older, they also feed on fruit. After defoliating your plant, the mature larva drops to the ground, where it pupates in a shallow depression in the soil, or in a pocket excavated just below the soil surface. An adult moth emerges, and the whole process begins again. This cycle is completed in one month, so there can be multiple generations each year.
Beet armyworm description
Larvae are smooth, pale green caterpillars, with several pale, wavy lines down the back and a broad stripe down either side. You may also see a dark spot above the second pair of legs. Other color variations can occur, depending on the food source and developmental stage. After 2 or 3 weeks of feeding, caterpillars will reach 1.25 inches in length. Adult moths are mottled brown and grey, with a 1-inch wingspan.
Damage caused by beet armyworms
Beet armyworms can destroy seedlings in only minutes. When feeding begins, the damage appears as clusters of circular or irregularly shaped holes in leaves. It can also cause flagging, a condition that slows or halts growth on one side of a plant. Larvae will feed on the crown of lettuce plants, killing them. As caterpillars get bigger, they can skeletonize all the leaves on a plant. Most fruit feeding occurs on or near the surface, and can be cut away, assuming other pathogens haven’t entered the fruit, causing disease or decay. Of course, you will want to wash the fruit thoroughly, to get rid of caterpillar feces. If beet armyworms feed on floral buds, the buds will abort.
How to control beet armyworms
In the home garden, natural predators are your plants’ best defense against beet armyworms. Predatory wasps will parasitize beet armyworm larvae, while big-eyed bugs, and minute pirate bugs will feed on the eggs. Spiders, damsel bugs, assassin bugs, tachinid flies, and lacewings will also feed on beet armyworms, so avoid using broad spectrum pesticides. In severe cases, you can apply spinosad or a specific type of Bacillus thuringiensis (ssp. aizawai).
Prevent beet armyworm invasions by monitoring nearby weeds, especially lambsquarters, goosefoot, and pigweeds for signs of egg clusters.
Harvesting your crops as soon as they are ready can also interrupt the lifecycle of these pests.
Beet armyworms have been known to travel as far as 10 feet during a night, putting most of your garden plants at risk. Monitoring for signs of beet armyworm infestation can help you prevent the problem from spreading.
Today, we are looking at some cutting-edge research in the world of plants. It may not make you a better gardener, but you’ll know more about plants than pretty much everyone else, and you may look at your plants a little differently.
Imagine, if you will, a tiny plant cell. Within that cell is a bubble of fluid, called a vesicle. Vesicles form naturally as plant cells eat and poop and go about their business. You can think of these bubbles as microscopic burps that stick around. Plant cells can also create vesicles on purpose. When this happens, they are called liposomes. [Keep in mind that this is an extreme oversimplification of what is actually going on, but you’ll have the basic idea.] A plant cell may have several vesicles, which cluster together into groups, called multivesicular bodies (MVB).
Vesicles are extremely small. They range in size from 30 to 150 nanometers (nm). A nanometer is one billionth of a meter. By comparison, plant cells range from 10 to 100 micrometers, while animal cells can be 10 to 30 micrometers. Micrometers (μm) are one millionth of a meter. A strand of human hair ranges from 17 to 181 µm.
Ergo, one human hair = 10 plant cells = 300 vesicles
What do vesicles do?
Plant cells use vesicles to move materials around, process proteins, maintain buoyancy, and all sorts of other things that we are only now learning about, though scientists have known about the existence of vesicles for a while now. What we didn’t know, until very recently, is that plant vesicles perform the same function as a type of animal cell vesicle, called an exosome, does. Their job is to take material from the interior of the cell, attach itself to the inner plasma membrane, create an opening, and then release the material into the apoplast, which includes the cell wall and the space between cells. Fungal cells do the same thing, but we didn’t know plants did until very recently.
In animal cells, there are specialized vesicles that check the load being carried by other vesicles, to see if the contents should be destroyed or moved to the apoplast. Plant cells do not have those specialized gatekeepers, so there is still plenty to learn.
Now, this may not sound like a Big Deal, but this is how cells communicate with each other, triggering plant growth and defensive measures. In fact, exosomes are directly related to the production of defensive proteins and RNAs used to fight disease. Exosomes are also used to move those defensive proteins from nearby healthy cells to a cell under attack by a pathogen, to create protective barriers against disease, and they can even enter invading cells to inhibit their growth. [If you are interested in this sort of thing, it is called host-induced gene silencing.] On the down side, exosomes also play important roles in malignancy.
In the not-too-distant future, we may be seeing artificially generated plant exosomes crafted to boost our plants’ ability to fight disease. Similar studies are being conducted to see if plant exosomes can be used in human medicine, such as exosomes found to reduce alcohol-induce liver damage in mice, or how vesicles of the ginger plant may be able to reduce inflammation in the human digestive system. For now, I will stick with ginger tea, but maybe exosomes were the reason it has been helping all along…
Bee's friend is a gorgeous flower that attracts pollinators and other beneficial insects
Also known as blue or purple tansy, or lacy phacelia, bee’s friend (Phacelia tanacetifolia) is a popular choice in agriculture as an annual ground cover. It is also grown as an insectary, to attract bees and beneficial predatory insects, such as hoverflies. Flowers remain open for an extended period with very little water, making it an excellent addition to your foodscape.
Bee’s friend description
Single, mostly unbranched, stems of bee’s friend can reach 4 feet in height, but most plants are only half that height. Curled leaves and stunning lavender-blue flowers make this a uniquely attractive plant. Most domesticated varieties are smooth-stemmed, while wild varieties are covered with stiff trichomes (hairs).
How to grow Bee’s Friend
Bee’s Friend seeds can be sown directly in areas that receive direct sun or partial shade, as soil temperatures warm in late spring. Stagger plantings for a more powerful impact. Seeds must be in complete darkness to germinate, so be sure to follow the planting directions on the packet and use an irrigation method that does not push the soil around too much. Misting is a good choice
Bee’s friend is considered one of the top 20 honey-producing flowers. Whether you raise bees or not, that much nectar is sure to bring bees and other pollinators to your garden in abundance! It makes an excellent plant for under or around fruit and nut trees, as a natural way of boosting pollination rates. The flowers are lovely, too!
Chinese yardlong beans rarely grow a yard long, but they get close. These impressive beans are fun to grow and delicious to eat.
Also known as asparagus beans, snake beans, and Chinese long beans, these annual legumes are a variety of cowpea, rather than a type of green bean.
Yardlong beans (Vigna unguiculata subs. sesquipedalis) are staples in Asian stir fry. They are easy to grow, highly productive, and they really make a statement.
Yardlong bean varieties
There are several varieties of yardlong beans, with varying maturity dates, colors, and growth habits. Here are just a few:
How to grow yardlong beans
Yardlong beans need lots of sun and heat and something to climb (unless it’s a dwarf/bush variety). Seeds should be planted 1” deep, well after the last frost date, and next to trellising, a stock panel, a tuteur, or some other structure. Yardlong beans prefer slightly alkaline soil with a pH of 6.0 to 7.5. You may want to succession plant at 2-week intervals for maximum harvest.
At first, it won’t look like much is happening. It may take 60 to 90 days before beans start flowering. Once they start, however, they are very productive. Bean pods tend to form in groups of two or more and they are a striking addition to any garden. And they taste good!
Harvesting yardlong beans
Yardlong beans are generally eaten before they reach full size. This means checking every day during peak production. They taste their best when about the diameter of a pencil. If you leave them on the vine longer than that, production will slow and the beans will become tough. You can, however, allow them to get close to full maturity and then harvest the beans for food and next year’s crop. Just be careful when harvesting. Do not damage the buds from which the beans grow. These buds can produce multiple beans throughout the growing season.
You can store yardlong beans in the refrigerator for several days before adding them to stir fry, casseroles and soups. These beans do not steam well.
Yardlong bean pests and diseases
Yardlong beans are not as susceptible to bean weevils as other bean species. Ants, aphids, and thrips, however, can cause problems. The most common pests are herbivores, such as rabbits, voles, and deer.
Delicious and attractive, yardlong beans also attract pollinators. Give them a try!
You can grow a surprising amount of food in your own yard. Ask me how!
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