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If you have a citrus tree, you may want to take a closer look for signs of purple scale in late spring and early summer, and again in autumn.  Purple scale feeding on an orange (Michal Maňas) CC BY 3.0 Purple scale insects suck the sap from citrus trees and they look like miniature mussels. Also known as mussel scale, orange scale, and comma scale, purple scale (Lepidosaphes beckii) are a type of armored scale that attach to banana, bay laurel, citrus, fig, mango, pear, and stone fruit trees and grapevines. These pests have several ornamental hosts that bear inspection:
Purple scale damage Like other scale insects, purple scale feed predominantly on leaves and young fruit, but they will attack all parts of a tree. You may see tiny yellow halos on the leaves. Purple scale feeding can weaken branches, disfigure fruit, and reduce productivity. Heavy feeding can lead to defoliation and twig dieback. In extreme cases, the tree can die. Populations of purple scale are usually low and found mostly in coastal regions, but mild temperatures, high humidity, and overcast skies can provide the conditions needed for a population explosion. You can find these pests in the cooler, shaded areas of trees. .jpg) Purple scale (USDA) Public Domain Purple scale identification
Purple scale insects aren’t actually purple. That sure would make them easier to find! Instead, they are dark brown and may have tan edges with a slight purplish tinge. Male purple scales are smaller and narrower than females. In both cases, you may see a slight bend at the narrow end of the scale. Male purple scales are 1/10” long and females are slightly larger. Male purple scale insects are tiny and they fly around in search of immobile females. Purple scale lifecycle Females lay 40 to 80 eggs under their protective covers. After the eggs hatch, crawlers emerge and scuttle to nearby fruit, leaves, and twigs, where they begin forming their own covers. At first, purple scale crawlers are covered with a mass of waxy threads. When they are about half-grown, their purplish-brown covers begins to develop. Once a female attaches herself, she stays put. Purple scale management Temperatures above 80°F are hard on purple scale, so their numbers are greatly reduced by the time summer is in full swing. But a second generation may appear in autumn and, in some years, a third generation may occur before winter cold brings them to a halt. Natural predators, such as parasitic wasps, twicestabbed lady beetles, and Australian lady beetles, take a big bite out of these pests. We can help them do their job by avoiding broad-spectrum pesticides and applying sticky barriers to the trunks of trees. Argentine ants are known to protect scale insects, so sticky barriers remove that protection. Purple scale prefer dusty conditions, so giving your citrus trees a quick shower with the hose can help.
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Rather than steamy backseat interludes, frenching describes the way leaves can become discolored or distorted.  Frenching of tobacco (R.J. Reynolds Tobacco Company, Bugwood.org) CC BY 3.0 US Frenching most commonly occurs in cotton and tobacco, but it may also be seen in citrus, sorrel, squash, and tomatoes. Peppers seem to be exempt from this condition, but no one knows why. Is frenching a disease? Well, yes, and no, and maybe. Since frenching is not entirely understood by botanists, its causes are currently referred to as “frenching factors”. These factors include predominantly fungal diseases, insufficient iron, poor drainage, alkaline soils, and temperatures above 95°F. [It sounds like I just described my yard!] In some cases, frenching is caused by specific bacteria commonly found in the soil (Bacillus cereus, Macrophomina phaseolina), the latter being one cause of damping-off disease. Frenching is also more likely when plants are grown in soil that stays moist during a drought. [I guess this means I should back off on watering my heavy clay soil quite so much in summer…] How to identify frenching While there are many ways that leaves can turn the wrong color or take on an abnormal shape, frenching has some consistent characteristics:
*Apical dominance refers to some plants’ natural tendency to have one main shoot that actively inhibits the growth of other shoots.  Frenching seen in tobacco leaf with dark veins and chlorotic margins (R.J. Reynolds Tobacco Company, Bugwood.org) CC BY 3.0 US These symptoms can be mistaken for aster yellows at first, but roots are not affected. This condition, regardless of its cause, starts out as tiny pinheads of chlorosis. New leaves are narrower than normal with wavy edges. As these leaves grow, only the midrib gets longer, pulling the leaves into strap-like shapes that end up looking more like stiff strings than leaves.
Scientists have found that autoclaving soil eliminates the frenching effect, but I’ll bet none of us have that option. There isn’t much we can do about the weather, either, but there are things we can do that will reduce the chance of frenching in our home gardens. Those actions include improving drainage, monitoring and maintaining a good soil pH, and feeding and irrigating plants regularly should do the trick. Have you seen frenching in your garden? Which plants were affected? Today, we are learning about the Krebs cycle. Wait! Come back! The Krebs cycle is how plants get energy from their food. Also known as the citric acid cycle, it won’t tell you how to grow bigger tomatoes or sweeter melons, but understanding the Krebs cycle gives you a better understanding of how plants grow and what they go through to make all those delicious things we eat.  Chef Krebs ready to cook up some food (Isuru Prabath) Pixabay We’ve already discussed the nitrogen cycle, the carbon cycle, and the water cycle. Those cycles describe how things needed by plants become available (and unavailable) as they change forms, moving through the environment. We’ve also discussed the Calvin cycle, which is part of photosynthesis. In the Calvin cycle, several anaerobic chemical reactions occur that allow plants to transform the carbon from CO2 into sugars. After those sugars are formed, the Krebs cycle begins. Messrs. Krebs and Johnson In 1937, a man by the name of Albert Szent-Györgyi was studying pigeon muscles. Stay with me, now! He received a Nobel Prize for his efforts, part of which was discovering several aspects of what later became known as the citric acid cycle. His discoveries were taken further that same year by Hans Adolf Krebs and William Arthur Johnson. [I guess they decided the Johnson cycle didn’t sound as impressive.] Krebs received the Nobel Prize for Physiology in 1953 for that work. [I don’t know why Johnson didn’t. Maybe he was too difficult to work with. I don’t know.] The Krebs cycle is part of the aerobic respiration process plants use to produce usable energy. Respiration, not what I expected When I hear “aerobic respiration” I start thinking about increased heart rates and time spent on a treadmill, but that’s not it. Aerobic respiration refers to one way that usable energy is formed. That usable energy is adenosine triphosphate or ADT. ATP is a molecule that carries usable energy around within a cell, taking it wherever it is needed. ADT is created when food (sugar) is burned with oxygen. I don’t know how plants burn anything but I keep getting images of little campfires in plant cells, so that’s kinda fun. Sugar as plant food I always thought plants simply drank sugar solution as food, but that’s not exactly how it works. Let’s put our steampunk magnifiers on and see what’s really going.  Plant cell (Lady of Hats) Public Domain How plants convert sugar into energy is far more complex and amazing than my little campfire, especially when you think of the scale at which all of this is happening. Plant cells are 10 to 100 micrometers across, depending on the species. This means you could put approximately 180 to 1,800 plant cells across the top of an American dime. [Human and animal cells are even smaller and they do similarly impressive things.] Now back to converting sugar.  Sugar crystals at x50 and x300 magnification (Gabriela P.) CC BY 4.0 To start, you need to know that sugar molecules are relatively large. To use them, plant enzymes go to work, breaking down those acidic glucose molecules into energy and pyruvic acid. That process is called glycolysis. More reactions occur, breaking the remaining bits down into carbon dioxide. As energy is released through these processes, it is moved to other molecules, called electron carriers. Electron carriers are like tiny cargo trucks. They form a chain called the electron transport chain. This transport chain creates ATP. As a side benefit, the processes also create the building blocks of several other molecules, such as amino acids.
For perspective, let’s say that a plant cell is the size of Arizona and the mitochondria are Phoenix. Arizona has a railway system that transports food. All the food comes from Texas and is too big to be packaged. This giant-sized food is taken to Phoenix where it goes through a 9-step process that converts the giant food into snack-sized portions that are small enough to fit on the trains. The trains take the food wherever it is needed. Put simply, that’s the Krebs cycle. But what does all this have to do with your garden? The bottom line, healthy plants produce bigger, tastier crops with less effort on our part. They are better able to defend themselves against pests, diseases, and weather extremes. All you have to do is make sure they get the right amount of water regularly and that the soil they are growing in contains the correct range of nutrients. Have you had your soil tested yet? What did you learn? The water cycle is a global phenomenon, but something similar is happening in your garden. In its simplest terms, the water cycle describes how water moves around on the Earth’s surface. It might be moving very slowly as ice in a glacier, whipping around on the wind as a gas, or flowing across the soil surface to water your bean plants. Regardless of its form, the mass of water on Earth stays relatively unchanged. The same is not true of your garden.  (Tedfloyd) Public Domain Unless you water exclusively from a rain barrel, the water for your garden probably comes from a spigot. If you’ve ever experienced a water main break or a flood, you know just how devastating too much water can be. Let’s compare the basic aspects of the water cycle from global and gardening perspectives. Evaporation The water cycle starts when the sun heats the surface of the planet. Water on the surface is converted to a gas that rises into the atmosphere. The soil of your garden, your driveway and house, and the concrete of your patio also act as heat islands, absorbing the sun’s heat and causing nearby water to evaporate. This is why it’s a good idea to give potted plants sitting on a concrete patio feet that raise them off the surface enough to allow air to flow. This will keep them cooler and reduce the amount of water they need.  Potted plants raised off the surface with feet or wheels are less likely to be cooked in summer (Kate Russell) Water held within plants is also released. As they perform photosynthesis, gas exchanges must occur. Water is released into the atmosphere as this happens. The combination of evaporation by heat and transpiration by plants is called evapotranspiration. Condensation As water vapor moves around in the atmosphere, the bits of water vapor bump into each other and grab on. Those clusters of water vapor keep getting bigger, condensing into fog, mist, and clouds. If you’ve ever been to Disney World in August, you know exactly what I mean.  Even hot, dry places get clouds (Kate Russell) Some plants thrive in misty, foggy, humid environments. Others end up with fungal diseases. If humidity is causing problems in your garden, be sure to prune your plants in ways that provide good airflow. Precipitation Water falling to the ground is precipitation. Globally, precipitation may mean rain, snow, hail, or sleet. In your garden, that precipitation may be rain, sprinklers, or a garden hose. As precipitation passes through the atmosphere, it collects particles along the way. Those particles are often car fumes, factory pollution, and dust, and those particles reach your soil right along with the water.  Rain refreshes everything in this California landscape (Kate Russell) Infiltration Water passing from the surface into the ground is called infiltration. Once the water has been absorbed by the soil, it is known as groundwater or soil moisture. Just because water is in the ground does not mean it is available to plants. Compacted soil has poor infiltration rates. And water does not spread smoothly through the soil in all directions. A fellow gardener called me with a zucchini problem. Her plant kept wilting, even though she was watering it regularly. I asked her if the water was reaching the roots. The phone was silent for a moment before she replied, saying she thought so. I had her go check. She called me back a few minutes later astounded. Even though she had been laying the hose next to her zucchini plant, the water was all veering away in another direction once it infiltrated the soil. I had her create an irrigation ring around her zucchini and it grew much better. Speaking of growing well, infiltration is how minerals get in the water that feeds our plants. As water enters the soil, some minerals are caught in solution. That solution is then absorbed by plants to provide both food and water. Now, some plant nutrients are more mobile than others. Immobile nutrients aren’t actually immobile, they just need a lot more water to move around. Blossom end rot is an example of irregular irrigation causing what looks like a nutrient deficiency. Most gardens on the West Coast of the US have abundant calcium, but may not be watered regularly enough. [Of course, a lab-based soil test is the only way you can learn what’s really in your soil.]  Urban drool (Kate Russell) Runoff
Water moving across the land is called runoff. Surface runoff, or urban drool, is wasteful and potentially dangerous. As suburban sprinklers miss their mark and water streets and sidewalks instead of lawns, they also carry oil, excess fertilizer, trash, and pollutants into waterways. Please make sure your sprinklers water where you think they do and adjust them as needed. As you can see, the water cycle is a series of steps that pass through various filters along the way. I once had a student create a variety of natural filtering systems for a science project. She used rocks, leaves, sand, and soil in separate containers to filter muddy water. Which material do you think did the best job of cleaning the water? I thought it would be the rocks, but I was wrong. It was the soil. In most cases, thrips are pests. Their feeding causes stippling, stunting, and scarring. Some varieties of thrips can even spread tomato spotted wilt and other diseases. But some thrips are predators  Black hunter thrips on finger (imgur) These tiny hunters may not look like much to us, but predatory thrips are other thrips’ worst enemy. In fact, predatory thrips control other thrips more effectively than other natural enemies. Mites, spider mites, and whiteflies are in the same boat. Predatory thrips are worth their weight in gold. These tiny hunters share many traits with their prey. Males are rare and females can produce offspring without mating. Predatory thrips also eat plant material, but they cannot survive without eating meat.  Banded-wing thrips (Robert Webster) CC BY-SA 4.0 While most thrips congregate in massive numbers, predatory thrips tend to be loners. There are four major species of predatory thrips:
Like other thrips, these insects are vulnerable to broad-spectrum insecticides and pesticides, horticultural oils and insecticidal soaps, so leave them as a last resort. Instead, create a habitat that attracts these and other beneficial insects. Your predatory thrips need food, water, and shelter, like every other living thing. You can buy predatory thrips. Or, you can simply provide a water source and a variety of places to hide, and these garden helpers will find your garden on their own.
Western flower thrips feed on much more than flowers. In fact, this group sucks the sap out of over 250 different plants. They can also bring tomato spotted wilt and other tospoviruses to your garden. And they bite!  Western flower thrips (Frank Peairs, CSU, Bugwood.org) CC BY 3.0 Western flower thrips (Frankliniella occidentalis) are native to the Southwestern United States but have spread to several other continents on contaminated plant material. [Yes, Virginia, invasiveness goes in all directions.] In fact, western flower thrips have earned the dubious distinction of being one of the world’s most important agricultural pests. And they have developed a resistance to many insecticides, so don’t bother spraying. Some scientists believe that western flower thrips have become such a problem and experienced such a significant population explosion as a result of genetic mutations caused by the insecticides we used to try to kill them. Oops. Western flower thrips description Male thrips of any type are rare. The same is true for this species. If you do see one, you might notice that they are yellowish-white. They are also larger than many other thrips, measuring up to a whopping 0.06 inches (1.4 mm). When male western flower thrips come together, they fight by flicking the tip of their abdomens at each other. Wouldn’t that be a sight?
Western flower thrips lifecycle Like other thrips, females do not need to be mated to produce offspring. Eggs are laid in unopened buds and under the epidermis layer of leaves, flowers, and fruit, causing discoloration and distortions. When those eggs hatch, hungry, mobile larvae start feeding. They use raspy mouthparts to shred and pierce to get at the sugary sap they crave. When not eating, they hide in tight little spaces where they are difficult to find. After they have eaten their fill, they enter a two-step, non-feeding pupal stage. In some cases, they drop to the ground to pupate. There can be up to 15 generations each year. Western flower thrips host plants It would probably be easier to list the garden plants not affected by western flower thrips, but you need to see just how damaging these micro pests can be. Members of the carrot, broccoli, citrus, legume, melon, mint, onion, sage, stone fruit, and tomato families are all susceptible to western flower thrips. So are apples, artichokes, beets, blueberries, figs, grapes, lettuce, pistachios, rye, strawberries, and wheat. See what I mean? These pests also feed on several native plants and many popular ornamentals, including carnations, chrysanthemum, gladiolas, impatiens, orchids, petunias, roses, and sweet peas. As thrips feed, their saliva damages the surrounding plant tissue. And nymphs feed heavily on newly forming fruit and leaves, causing damage and spreading disease.  Western flower thrips damage to bean leaf (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0 US But they aren’t all bad. Western flower thrips also feed on certain mites that attack cotton crops. [I still don’t want them in my garden.] Western flower thrips damage You may have to look closely to see these pests, but the damage they cause is more visible. As they feed, they leave behind scarring and stippling of petals, leaves, and other plant parts. You may also see distorted growing tips, pimpling of flower petals, or leaf silvering. The damage varies based on where and when the damage occurred. In some cases, you won’t see it until much later. This later damage may include distorted or spotted fruit, which bruises more easily, Fruit splitting may also occur and Western flower thrips are the main vector of tomato spotted wilt.  Western flower thrips on damaged nectarine leaf (Carroll E. Younce, USDA, Bugwood.org) CC BY 3.0 US Being attracted to bright colors, especially blue, white, and yellow, these pests will land on people wearing those colors and bite them. Thrips won’t drink your blood or make you sick, but you might be uncomfortable for a while. And you can use that information to help control these pests.
Blue sticky sheets are very effective at attracting and capturing western flower thrips. Sadly, beneficial hoverflies are also attracted to those blue sticky sheets. You can protect those garden helpers by surrounding the blue sticky sheet with a mesh that will allow the thrips through, but not the hoverflies. Reflective mulches actively discourage western flower thrips and insidious flower bugs are particularly fond of western flower thrips. For dinner. Names can be misleading. While it’s true that onion thrips feed on onions, they also eat asparagus, beets, broccoli, cabbage, cauliflower, cucumbers, garlic, leeks, melons, potatoes, pumpkins, strawberries, and zucchini, along with several other fruiting and ornamental plants. If that weren’t trouble enough, they can carry serious plant diseases, too.  Onion thrips (Alton N. Sparks, Jr., UGA, Bugwood.org) CC BY 3.0 Also known as potato thrips, tobacco thrips, and cotton seedling thrips, onion thrips (Thrips tabaci) hide in many herbaceous ornamentals, tucked into cramped quarters where they are easy to overlook. Onion thrips description Like other thrips, these garden pests are very small. Maxing out at 0.05 inches (1.3 mm), you could fit 13 or 14 of them end-to-end across an American dime. Adult onion thrips can be yellow to dark brown and sometimes black. Most of them are female. Using a hand lens, you can see that their wings have a single, central vein and long hairs. Eggs are white at first but turn orange a few days later, just before hatching. Larvae are also yellow to brown.  Onion thrips second instar, leaf damage, and frass (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0 US Onion thrips lifecycle Females use an ovipositor to cut into leaf tissues. Then she tucks her eggs in, under the epidermis, of up to 80 leaves. Less than a week later, those eggs hatch and start sucking the sap from those and neighboring leaves. There are two larval stages during which a lot of sap is eaten. Larvae then stop eating and go through prepupal and pupal stages. Adults generally only live for two or three weeks, but they can overwinter in legumes, grains, weeds, and plant debris. Damage caused by onion thrips To get at the sap they love, thrips use their raspy, piercing mouthparts to shred and penetrate the surface of predominantly young leaves and flower petals, breaking open plant cells and drinking their fill.  Onion thrips feeding damage on onion (Scot Nelson) Public Domain Since they are feeding on young parts that continue to grow, the damaged areas become elongated, silvery streaks. You may also see leaf curling, stippling, scarring, stunting, leaf tip browning, white patches, and smaller crop sizes. On cauliflower, you may see brown streaks on curds. Damaged areas of leaves cannot perform photosynthesis, injured areas lose water faster than normal, and provide points of entry for other pests and diseases, such as bacterial rot. But onion thrips can infect your plants with a variety of diseases simply by feeding. Onion thrips are vectors (carriers) for Impatiens necrotic spot virus (INSV), Iris yellow spot virus (IYSV), purple blotch, strawberry necrotic shock virus, tobacco streak virus, and tomato spotted wilt virus (TSWV). Onion thrips management Onion thrips are easily dislodged with a garden hose, but that won’t fix the problem. There are some cultural practices you can adopt that will help reduce onion thrips problems. First, clean up plant debris at the end of each growing season. When planting, only use certified pest- and disease-free seedlings, seeds, and onion sets. Monitor the areas surrounding your garden for signs of onion thrips and other pests, and remove volunteer plants that may harbor pests and diseases.  Onion thrips nymphs in new growth, between onion leaves (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0 US Beneficial insects, such as lacewing larvae, pirate bugs, and predatory thrips will help in the fight against onion thrips, so avoid using broad-spectrum pesticides and insecticides.
Since healthy plants are better able to protect themselves against onion thrips, water and feed your plants with that goal in mind and get your soil tested by a lab. You’ll be glad you did. Bean thrips (Caliothrips fasciatus) were first found in the 1800s on orange leaves, but they prefer eating beans and other legumes. That being said, these California natives are also found on avocado, pear, and walnut trees, in the navels of navel oranges, mandarins, and other citrus, as well as cantaloupes and other melons. They don’t eat all of these plants, but they do like using them for shelter because of how close they are to your legume crops.  Female bean thrips (Mr Thrips) CC BY-SA 3.0 Known as California bean thrips and North American bean thrips, these pests are also called citrus thrips, which is incorrect. Citrus thrips (Scirtothrips citri) are another species. These are also not Asian bean thrips (Megalurothrips mucanae), another entirely different species that we will explore another day. While different, these species have a lot in common with our California bean thrips. Bean thrips identification Adult bean thrips have dark, greyish-black bodies with white wing bands. The legs have light and dark bands and both genders have fringed wings that they fold over their backs when at rest. Of course, these pests are about the size of any letter on an American penny, so you probably won’t see all that. If you use a hand lens, you can. You would also be able to see that larvae are yellowish to orange. Those larvae are about 1 mm long at their biggest. Eggs are even smaller, at only 0.008 inches. If you could see them, you’d notice that they are banana-shaped. What you are more likely to see is the tiny black frass (bug poop) deposits which are often found on the top and underside of leaves, in and around citrus navels, and where clusters of fruit touch. You will also see the damage they cause.  Bean thrips on the underside of a leaf (Whitney Cranshaw, Colorado State University, Bugwood.org) CC BY 3.0 US Bean thrips damage Both larvae and adults feed on leaves and growing tips. As they feed, they cause leaves and growing tips to turn brown and distorted. Silvering and premature defoliation can also occur, reducing plant vigor and resulting in sunscald. Bean thrips also feed on immature beans. Bean thrips lifecycle Female thrips lay eggs in the leaves and fruit of legumes. Legume fruits are also known as pulses. Pulses are the beans and lentils we enjoy eating. When bean thrips eggs hatch, first and second instar larvae feed heavily on leaves, growing tips, and immature pulses before they fall to the ground and go through two-stage pupation. Winged adults emerge and the cycle starts again. Like most other thrips, mating is not needed for reproduction to occur: unfertilized eggs produce male offspring and fertilized eggs produced females, but there’s more to it than that. Research has found that females generally only live 20 to 55 days. At the 10-day mark, short-lived females stop producing female offspring. If they happen to live for more than 50 days, they will produce female offspring until the 30-day mark. How does this stuff evolve? And how do they know? It baffles me. Bean thrips control Bean thrips are very bad fliers. They can only fly a few feet in a crazy zig-zag or spiral pattern. But they can catch rides on the wind, so you have to monitor plants for signs of thrips during warm and hot weather. Bean thrips thrive in hot weather and there isn’t anything you can do about that. But there are steps you can take to make your garden less appealing to bean thrips. First, they like to hide out in weeds, such as prickly lettuce (Lactuca serriola) and wild blue indigo (Baptisia australis) so keep weeds, especially those in the legume family, several feet away from your garden beds.  Severe bean thrips infestation of wild blue indigo (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0 US Yellow sticky sheets attract and capture all sorts of thrips and other pests and they are inexpensive. While research has shown that green sticky sheets are more effective at capturing bean thrips in particular than other colors, you’ll probably do fine with the yellow.
So, what’s going on (and under) your plants’ leaves? Even if you aren’t growing avocados, avocado thrips are pretty fascinating. [Just a reminder, the word thrips is the same for one thrips or many thrips.]  This chili thrips looks a lot like an avocado thrips Aderksen) CC BY-SA 3.0 Avocado thrips (Scirtothrips perseae) are native to Mexico and Guatemala. In 1971, a single female was stopped at the border. By 1996, avocado thrips were found throughout California and Hawaii. By 1999, it was estimated that avocado thrips infested 99% of California’s avocado trees.
Damage caused by avocado thrips These pests may be tiny, but they can cause significant damage. Thrips populations explode rapidly in spring and autumn, leading to defoliation and premature leaf drop. This, in turn, reduces tree vitality and crop size. The biggest problem with avocado thrips is the scabby, brown scars on the fruit they create. These damaged areas don’t look very nice and they can create points of entry for rot and other diseases and pests. Avocado thrips identification These suckers are tiny. At 0.03 inches long (0.7 mm), you could put 23 adult avocado thrips end-to-end across a dime, making them one of the smaller thrips species. If you could see them up close, you would see that adult avocado thrips are straw-colored, with three red spots on the top of their heads, between their eyes. Those dots are called ocelli and they are light-sensitive organs. They also have yellow abdomens with brown stripes, but their bellies may look greenish because of all the chlorophyll they consume. [I was unable to find a free-to-use image of an avocado thrips, but they look enough like chili thrips that that’s what I used above.] Avocado thrips first instar larva are pale whitish-yellow, while second instar larvae are bigger and brighter yellow. Avocado thrips lifecycle Avocado thrips have six distinct life stages and adult females can lay eggs whether they have mated or not. Unfertilized eggs produce males and fertilized eggs produce females. How’s that for efficiency? Eggs are laid on immature leaves and fruit. When they hatch, they begin feeding in the first larval stage. Then they enter a voracious second larval stage, followed by two non-feeding pupal stages. These pupae hide out in cracks and crevices in the bark and on branches, or in leaf litter (duff) under the tree. Flying adults emerge and begin feeding on leaves and fruit as they search for mates and good sites for egg-laying, and the cycle continues. Avocado thrips management Scorching summer heat seems to do a number on thrips, but the eggs they lay beforehand are waiting for conditions to improve. You can use yellow sticky sheets, mulch, and natural enemies to battle avocado thrips. Those natural enemies include various green lacewings and a fascinating predatory thrips called Franklinothrips. I can’t make this stuff up, but we will learn more about that pest later this week. Some predatory mites also like to feed on avocado thrips larvae. To help these predators succeed, avoid using spinosad and other insecticides. Avocado thrips and several other pests are attracted to yellow sticky sheets. These are inexpensive and very effective, just keep them away from your hair. Also, studies have shown that mulching under (but not touching) trees can result in 50% fewer thrips making it to adulthood. This is because 78% of larvae drop from the tree to pupate on or in the soil. Apparently, a mulch of arborist chips or composted organic yard waste contains enough different predatory nematodes, fungi, bacteria, and other killers of thrips to put a serious dent in their population. Three cheers for biodiversity! To reduce the chances of the problem in the first place, only buy certified pest- and disease-free rootstock. Of course, while they do it badly, thrips can fly, sort of, so a brisk breeze may be all they need to reach your avocado tree. Be on the lookout. Remember, they like to hide on the underside of avocado leaves. Life in a greenhouse can be idyllic if you are a seedling, whitefly, or a thrips. The same conditions that provide for optimal plant growth also create a perfectly protected habitat for pests, such as greenhouse thrips. Of course, those pests then escape their Eden and end up in our gardens.  Greenhouse thrips, multiple life stages (Whitney Cranshaw, Colorado State University, Bugwood.org) CC BY 3.0 US The thrips family is huge, with thousands of varieties worldwide. Most of them are pests, sucking nutrient-rich sap from leaves, buds, and stem tips. But the insects themselves are very tiny (1 mm long or less). In most cases, you will see the damage they cause before you see the actual insect. Invasive greenhouse thrips (Heliothrips haemorrhoidalis) are also known as glasshouse or black tea thrips. They were originally from Brazil but are now found pretty much everywhere except extremely cold regions. Greenhouse thrips damage These pests prefer perennials with thick, broad leaves, which means their diet often includes avocado, bay laurel, and citrus. They also feed on coffee, guava, kiwifruit, macadamia, pecan, stone fruits, and stone pine, along with several ornamentals, including azalea Grecian laurel, rhododendron, and St. John’s wort. Feeding punctures result in stippling that can expand to create whitish-gray areas on leaves, reducing plant vitality. Severe infestations can cause defoliation. You may also see leaf curling and cupping. These pests can carry tomato spotted wilt virus. The biggest problem with thrips feeding is the scarring, cracking, and lesions they cause on fruit.
Greenhouse thrips identification Adult thrips have black bodies with white legs and wings and yellow bellies. Their wings are not well-designed for flight, being fringed hairs instead of membranous panels. To move quickly, thrips use a clap-and-fling method which is why you may suddenly see something shoot by as you work in your garden.  Thrips forewing (Felipe N. Soto-Adames, FDACS DPI) Public Domain Greenhouse thrips have heads and jaws that are sideways and somewhat backward. I have no idea why. The technical term is ‘hypognathous head’. Larvae and pupae are really tiny. You could place 35 of them, end-to-end, across an American dime. Using a hand lens, you would see that they are white to pale yellow with red eyes. You may also see a blob of green poop (frass) on the rear end of larvae. Scientists believe this is used to deter predators. I’ll bet it works, too! Eventually, that frass falls off. If you see tiny black flecks on the underside of leaves or caught up in fruit clusters, it’s probably greenhouse thrips.  Thrips nymph (M. J.) CC BY-SA 2.0 de Greenhouse thrips lifecycle As far as we know, there are no male greenhouse thrips in California, which might sound like a good thing with regards to pest control, but it has no effect on the local thrips population. Thrips can reproduce through something called parthenogenesis, which means fertilization of the ovum is not needed to produce baby thrips. Each female lays up 60 eggs in her lifetime. Those eggs are inserted into fruit or leaf surfaces. As they grow, they can create a swelling known as an egg blister. Four to five weeks later, those eggs hatch, and larvae start feeding. There are usually five or six generations each year, but there can be up to twelve generations if conditions are good. That ends up being a lot of thrips.  Robber fly eating a thrips (Shyamal) CC BY-SA 3.0 Greenhouse thrips management
These pests, like many others, have developed resistance to insecticides and spinosad, so don’t bother. Instead, put nature to work for you. Natural predators, such as robber flies, will put a dent in thrips populations. If thrips are a serious problem in your landscape, you can buy predaceous thrips and you may be able to find egg parasites, such as Thripobius semiluteus or Megaphragma mymaripenne, that you can release in your landscape. Cultural thrips controls include thinning fruit to reduce hiding spaces (and improve fruit quality) and harvesting fruits as soon as they are ripe. Wheel bugs are big, armored, and dangerous.  Wheel bug (Ragesoss) CC BY-SA 3.0 When disturbed, these slow-moving giants can inflict a painful bite that starts out feeling like a bee sting, followed by days of numbness. But that’s okay because wheel bugs more than make up for that possibility by the number of garden pests they hunt down and devour. Native to North America, wheel bugs (Arilus cristatus) are a type of assassin bug. At up to 1½” in length, they are one of our largest true bugs. True bugs (Hemiptera) have piercing and sucking mouthparts and they go through an incomplete metamorphosis. Unlike aphids and leafhoppers, which feed on the sap of our plants, wheel bugs pierce, liquify, and consume other insects. Wheel bug identification Wheel bugs are easy to identify but they are shy. Besides being large, they don’t move very quickly. This makes it easy to take the time to see details. They do fly, however, so don’t startle them. The first thing you will notice about a wheel bug is its dorsal crest. Dorsal crests are raised ridges along the back. In the case of wheel bugs, that crest looks like part of a cog or spoked wheel. And when they fly, wheel bugs make a buzzing noise and are easily mistaken for grasshoppers .png) Wheel bug on pool skimmer (Marmelmm) CC BY-SA 3.0 Wheel bug adults are usually gray to brown. They may look nearly black right after molting. And males are slightly smaller than females. Wheel bug nymphs do not have the cog-shaped crest. Instead, they look more like spiders with red or orange abdomens.
Wheel bug lifecycle Wheel bugs mate in autumn. Females lay clusters of 40-200 brown, cylindrical eggs on bushes, trees, and other surfaces. After laying eggs, the female eventually dies. Eggs hatch in spring and the nymphs go through five molts before reaching adulthood. Wheel bug diet Wheel bugs feed on a variety of garden pests, including cabbageworms, caterpillars, Japanese beetles, Mexican bean beetles, and tent caterpillars. Wheel bugs are usually active during the day but may hunt at night in areas with lights. When they hunt, they capture their prey with their front legs and inject it with paralyzing and dissolving enzymes.  Wheel bug consuming Japanese beetle (Andy McLemore) CC BY-SA 2.0 While wheel bugs also prey on honey bees and ladybugs, they are considered highly beneficial. Their presence indicates a healthy environment with abundant biodiversity. To encourage wheel bugs in your landscape, avoid using broad-spectrum pesticides and insecticides, and add some goldenrod and sunflowers.
Adding sugary, nutrient-rich molasses to gardens and compost piles is said to feed important microorganisms, raise sugar levels in your plants, and kill pests. Truth or myth? Let’s find out.  Molasses (Marshall) CC BY 2.0 What is molasses? As a young child, I thought nothing tasted better than freshly baked bread that had been slathered with butter and molasses. I still love it. But what is molasses and why do people say it’s good for your garden? Molasses is the sweet, syrupy residue left over after processing sugar cane and sugar beets to make sugar. Also known as black treacle (UK), molasses is mostly sugar. It also contains calcium, iron, magnesium, manganese, phosphorus, potassium, sodium, and a little zinc. Does molasses feed microorganisms? The microorganisms that support our plants love sugar and all those minerals. Adding molasses to compost piles and planting beds makes sense. Provide food for microorganisms and they will multiply, doubling their population every 20 minutes, for as long as the food supply lasts. Therein lies part of the problem. Natural processes take eons to find balances that allow them to continue. The variety of bacteria and other microorganisms responsible for decomposition, nutrient transfer, and healthy soil exist in a dynamic dance of available resources. Population explosions rarely end well and the same is true for all those microorganisms. As soon as the molasses is gone, they die. Your plants will get some nutrients from all those dead organisms. And your compost pile will cook faster until you wet it down tomorrow and wash the sugars away. But those potential benefits are short-lived and have not been demonstrated in lab or greenhouse tests. Yeasts tend to grow faster than the other organisms when fed molasses, which may not necessarily be what you want. To maintain healthy microorganism populations, you are better off adding healthy foods, such as wood chips, compost, and other organic matter, rather than the junk food rush of molasses.
Can molasses kill insects? If you pour molasses on a soft-bodied insect, it will die. This doesn’t happen because molasses contains some magical property or the pest’s supposed inability to process sugar. The insect would simply suffocate. And saying that eating sugar will kill an insect is ridiculous. Sap is sugar water. Beetles and cockroaches eat candy bars and cookies. When sugar is eaten by insects, they do not explode. They fart like everyone else. [Did you know that termite farts are responsible for generating 20 million metric tons of methane each year? I didn’t either.]  Ants eating cake icing (Judgefloro) Public Domain So, there you have it. Molasses can briefly boost microorganism populations. It will not significantly increase sugar levels. And it is not an insecticide. Rather than pouring it on your garden, save molasses for your toast. Or, try your hand at George Washington’s recipe for small beer (below).
We’re all familiar with the NPK of fertilizer fame, but what about vanadium? When it comes to plant nutrition, most of us are familiar with nitrogen, phosphorus, and potassium. These are the entrees of a plant’s diet and they are called primary macronutrients. These macronutrients are used for leaf, root, and fruit growth, respectively. [Of course, that’s a massive oversimplification, but it’ll do for now.] .jpg) Vanadinite (Géry Parent) Copyrighted free use Secondary macronutrients are the side dishes. They include calcium, magnesium, and sulfur. Continuing with our menu motif, I guess we could say the remaining micronutrients are the herbs and spices of a plant’s meal. We used to call these flavorings trace elements and they include boron, chlorine, cobalt, copper, iron, manganese, molybdenum, nickel, selenium, silicon, sodium, zinc, and vanadium.
What is vanadium? Vanadium is a biochemically active metal and it is the 20th most abundant element in the Earth’s crust. It is estimated that 100,000 metric tons of vanadium are released into the atmosphere each year by burning fossil fuels, so there’s no shortage. We used to think that vanadium (V) was toxic to plants. Now we know it’s not that simple. Vanadium is a tough nut to crack. Even though there’s plenty of it in most soils, only 1% of what’s there ends up being soluble in water, so it isn’t always easy for plants to absorb it. Also, vanadium can accumulate in plant tissues to the point that it becomes toxic. To makes things even more confusing, vanadium is believed to mimic phosphorus, tricking plants into absorbing vanadium when what they need is phosphorus. But plants do need vanadium. How do plants use vanadium? Vanadium is used by some plants as a substitute for molybdenum. Molybdenum helps plants use nitrogen by working with certain enzymes. But recent research has shown that there’s a lot more to vanadium than that. Vanadium plays a role in the movement and absorption of other nutrients, activating certain enzymes, and allowing for (and blocking) the absorption of several different elements. Vanadium has been found to stimulate corn, pepper, rice, tomato, and other plants’ growth and flowering. Lab studies have shown that vanadium is responsible for increased levels of amino acids, chlorophyll, and sugar, as well as N, P, K, Ca, Mg, Cu, Mn, and B. Adding vanadium made the plants being studied grow more, produce more flower buds, and sped up the flowering process. It also helped counteract the negative effects of too much copper and other metals. Other studies have shown that vanadium helps convert atmospheric nitrogen (which most plants cannot use) into ammonia (which plants can use as a nitrogen source). It does this by waking up a specific enzyme, called nitrogenase. Before you start adding vanadium to your soil or fertilizer mix, you need to know that this is one of those too-much-of-a-good-thing-is-a-bad-thing situations. Vanadium toxicity can harm your plants by causing a build-up of potassium, magnesium, and manganese in plant leaves, causing a domino effect of malnutrition. Since most soils already have plenty of vanadium, regular irrigation and periodic soil tests are your best bet. Soil tests don’t (yet) include vanadium in their results, but they will help you see if any other imbalances are present. My mother lived alone on 97 acres in Upstate New York. It was an old farmhouse that had been added onto over the years and generations. On that property, there had once been a barn, but it had fallen or been torn down years before, leaving a cracking concrete slab, some steps, and a silo. One of her many dreams was to transform the space into a folly, complete with special plantings, tables and chairs, and a spiral staircase to the top of the silo, where she would use a telescope to look at the stars. That particular dream never materialized, but we can use her idea to inspire some ideas of our own.
What is a folly? The word folly refers to someone lacking in good sense. Architecturally, a folly is an outlandish building or other structure built primarily for decoration. These structures are more extravagant than would normally be seen in a garden.  Beech Hill Hotel Folly (John C) CC BY0-SA 2.0 Follies were first created in the 16th and 17th centuries but became popular in the 18th century. People added decorative Roman temples, pyramids, and medieval castles to their gardens and surrounded these structures with a wide variety of plants. Follies were often named after their creator, as in so-and-so’s folly. Follies have certain characteristics that can guide you in creating your own folly:
 Folly in the woods (Robin Webster) CC BY-SA 2.0
Each area of your landscape has its own set of characteristics: wind and sun exposure, soil structure, moisture levels, and plants that thrive. What if you were to look at each of those spaces with an eye to creating a folly, or adding a touch of silliness? That’s one of the nicest things about gardening – there are no rules. We can create whatever we’re willing to invest the time in  The Facetower (Forbidden Corner) CC BY-SA 4.0 One of those characteristics, the “fakeness” of follies, opens up several possibilities to the home gardener. You may not be able to recreate a full-scale stone castle next to your tomato plants, but nothing says you can’t use that curb-scored iron headboard or plastic kiddie climbing toy to create a folly of your own.
If you could build any sort of folly in your yard, what would it be? Personally, I’d love one of those Baba Yaga houses with the chicken legs, but that’s just me. A rose by any other name…just might be a peach tree. It’s true!  A lovely rose (Stuart Russell) The rose family (Rosaceae) includes a surprising number of popular fruit trees. Apples and pears, known collectively as pomes, are in the rose family. So are the stone fruits, such as almonds and nectarines. Cane fruits, such as blackberries and raspberries are part of the rose family. So are strawberries. So, how can all these different plants be related? Let’s find out. Rose family characteristics The rose family is large and diverse. It contains herbs and shrubs, along with all those trees. But they do share many common characteristics. Most of them are deciduous, deep-rooted, woody perennials. In general, leaves are arranged spirally, with a few exceptions, with serrated edges. You may see spines along the midrib and extrafloral nectaries are often present. Flowers of the rose family are famous for being showy. If you look closely, you can see that the bases of the petals, sepals, and stamens are fused together into a cup-shaped structure called a hypanthium.  'Rosa' hypanthium surrounding several achene fruits (RoRo) Public Domain Fruits of the rose family come in several forms:
While most members of the rose family are edible, the seeds often contain amygdalin, which can release cyanide when chewed. [But you’d have to eat an awful lot to have any problems.] Like most families, there are some members of the rose family you wouldn’t want to invite to your garden. Weedy rose family members Not all members of the rose family are lovely, sweet, and delicious. Some can be a royal pain. Pale biddy-biddy (Acaena pallida) is a rose family member, native to the Southern Hemisphere, but now registered as a noxious weed elsewhere. Even our familiar thornless firethorns (Cotoneaster), hawthorns (Crataegus), thorny Pyracantha, and roses (Rosa) are technically invasive plants. Birds eat the seeds found in our landscapes, they then fly away and deposit those seeds where they will grow and displace native plants. This causes a domino effect of destruction for native birds, insects, and other living things. I’m not saying you shouldn’t grow these plants. I’m just saying there are consequences to the surrounding environment.
Growing rose family plants
Rose family members grow best in locations with loose soil, good drainage, and full sun. These plants have chilling requirements that must be fulfilled before fruit can be produced, so be sure to pick varieties and cultivars that match the chill hours expected in your yard. Rose family pests and diseases It would probably be easier to list the pests and diseases that do not affect members of the rose family. The same characteristics that make these plants appealing to us attract insect pests. Of course, it depends largely on which plants you’re growing. In most cases, aphids, borers, caterpillars, leaf miners, Fuller rose beetles, leafhoppers, mealybugs, root nematodes, sawflies, scale insects, spider mites, thrips, and whiteflies are common pests. Rosaceae are susceptible to several fungal diseases, including black spot, gray mold, powdery mildew, rusts, stem canker, and Verticillium wilt. Bacterial blight and fireblight can also occur. Learn more about the specific plants you are growing to know how to protect them against these problems. Speaking of growing, how many members of the rose family are in your garden? Tell us in the comments! The Ribes plant family is a small but delicious group that includes currants and gooseberries. Botanically, Ribes is a genus (which is why it is italicized). The family name is Grossulariaceae, but Ribes is the only member of that family, so we will overlook that technicality. Ribes are native to the Northern Hemisphere.  Red currants (RitaE) Pixabay This pair of edibles is an interesting mash-up of characteristics. Gooseberries have thorny exteriors but tend to be well-behaved and undemanding. Currants, on the other hand, may look docile and approachable, but these plants defy description and can bring serious problems to a region. In fact, there are laws against growing Ribes in some regions! The Ribes family was banned in 1920. [I told you they were scoundrels!] This ban was put in place because Ribes can host white pine blister rust (Cronartium ribicola). This fungal disease has been devastating to East Coast white pines. Don’t worry, though. That ban was partially lifted in 1966, as resistant cultivars were developed. If you live in New Hampshire, North Carolina, or West Virginia, you are still not allowed to grow Ribes plants, as far as I know. If you live in Massachusetts, New Jersey, Rhode Island, or Delaware, you’ll need a permit. Currants Now, we’re not talking about those tiny raisins made from Corinth grapes when we say currants. Currants are small red, black, or white berries that grow in clusters. Scientists are still wrestling with this group, which defies classification. You can read more about that in my post on currants.  Golden currants shrub courtesy of Gary MacPherson at ColoradoHardyPlants Gooseberries Gooseberry plants have spiny stems and branches, making them tricky to work with. Since branches only produce fruit in a single season, removing heavily laden stems makes them easier to work with, plus it lets light in for new branches to grow. You can find sweet dessert varieties and tart culinary varieties. Gooseberries can be green, white, yellow, or reddish-purple.  Gooseberries (Kornelia and Hartmut Häfele) CC BY-SA 3.0 Ribes pests and diseases
Aphids, brown marmorated stinkbugs, clearwing moth larvae, currant borers, gooseberry fruitworms, gooseberry sawflies (Nematus ribesii), also known as currant sawflies, mites, imported currantworms, and the larva of some moths and butterflies are common Ribes pests. And birds. Problems are more commonly caused by mineral imbalances in the soil or improper irrigation. These plants are susceptible to several fungal diseases, such as American gooseberry mildew, anthracnose, currant cane blight, gray mold, leaf spot, powdery mildew, rust, and septoria leaf spot. Avoid overhead watering and be sure to provide good drainage. Ribes grow best in cool, moist surroundings with good drainage, but partial shade and regular irrigation make them possible elsewhere. These plants can be grown in containers and are self-pollinating. Ribes take well to regular pruning, making them excellent patio or balcony plants, and renewal pruning each winter keeps them healthy and productive. Ribes berries are delicious and their flowers provide nectar and pollen to a wide variety of butterflies. The mallow family (Malvaceae) is a mixed bunch. It contains several weeds and some favorite crops. It also includes several ornamentals, such as hibiscus, hollyhocks, and linden trees. Scientists are still arguing over the specifics of the mallow family, but let’s see how it applies to gardening.  Hollyhocks (Stan Shebs) CC BY-SA 3.0 Mallow characteristics Most mallows are shrubs or trees that put out taproots. Leaves tend to alternate along a stem and are lobed. The leaves are usually smooth-edged. When they are toothed, you will see a vein reaching the edge of each tooth. You will also see a small, leaflike appendage at the base of each leaf, called a stipule. Stems of mallows contain mucous and may be covered with prickles. Mallow flowers tend to be large and showy. Fruits are usually capsules, nuts, or schizocarps. Members of the mallow family readily self-seed an area. Mallows grow best in full sun with regular irrigation in summer. .jpg) Cocoa tree and opened fruit (USCapitol) Public Domain  Durian fruits (W.A. Djatmiko) CC BY-SA 3.0 Edible mallows Cocoa, kola nuts, and okra are members of the mallow family. So is durian, a tropical tree that produces giant-sized fruit. Some people love durian and others say it stinks. While you can’t eat it, cotton is also a member of this family. Even most of the mallow weeds are edible, but you probably don’t want to encourage them in your garden. .JPG) Okra with immature pod (Delince.J) CC BY-SA 3.0 Weedy mallows Mallow seeds have thick coats that protect them from harm. Those coats also slow germination until conditions are ideal. Very often, those seeds are weed seeds, and they can spread like crazy. Most mallow weeds are invasive to the US and are easily mistaken for one another. Common mallow weeds include:
Many of these weeds are edible, but they can also carry disease.
Mallow pests and diseases
Weedy members of the mallow family can carry several diseases, including rusts, tomato yellow leaf curl, and tomato spotted wilt. Members of the mallow family are also susceptible to bacterial leaf spot, gray mold, and phytophthora blight. Aphids and spider mites are the most common pests. If you grow hollyhocks and okra, you may want to keep them at a distance from each other, to prevent the spread of disease. Finally, the marshmallow plant (Althaea officinalis), a native herb of Europe, is a member of this family and its roots were used to make marshmallows some 4,000 years ago in Ancient Egypt. Today, marshmallows are made out of sugar and gelatin. There’s more to the grass family than just your lawn.  Grass blades (LoggaWiggler) Public Domain Grains and grasses (Poaceae) have long been a part of home gardens, landscapes, and agricultural fields. This group is the fifth-largest plant family and it includes cereal grains, bamboo, lemongrass, sugarcane, and coffee. [That last one surprised me, too.] Let’s see how these plants are all related and how many of them may be good additions to your garden. To start, members of this group are usually divided into grasses and cereal grains. Grass plants Grasses are monocots with fibrous roots and hollow stems, except at the nodes. They have narrow leaves that appear alternately up the stem. Each of those leaves wraps around the stem, creating a leaf-sheath, rather than growing out of a petiole. Very often, you will see a fringe, called the ligule, where the sheath meets the stem. This growth is believed to keep water and pests from entering. It can also be used to help with plant identification.  Diagram of a typical grass plant (Kevinsong) CC BY 3.0 Grass plants reproduce most commonly by seed, though some use rhizomes to create daughter plants, known as tillers. Grain seeds are encased in simple dried fruits called caryopses. Flowers of the grass family tend to form spikelets. These plants can be annuals or perennials, depending on the species.  Coffee plant in flower (Marcelo Corrêa) CC BY-SA 3.0 Unlike most other plants, the meristem tissue [think undifferentiated stem cell] of grass family plants is found near the base of the plant, rather than higher up. This allows the plants to recover from grazing (and mowing). These plants are all heavy feeders that use a lot of nitrogen. Planting them in blocks, rather than rows, increases pollination. Cereal grains Cereal grains are classified as warm-season or cool-season cereals. Corn, millet, and sorghum are warm-season cereals that need lots of sunlight and heat to thrive and are better able to withstand drought. Cool-season cereals include barley, oats, rice, rye, spelt, wheat, and wild rice.  Oats and wheat (Kate Russell) Many people consider amaranth, buckwheat, and quinoa to be cereal grains, but they are not. Instead, these are all broadleaf (dicot/eudicot) plants known as pseudocereals. Other seeds that are not grains include lentils, peas, and other legumes. And that “recreational/medicinal” grass? It’s not a member of this family either.
Grass family pests and diseases Grains and grasses are prone to fungal diseases, such as leaf scald, leaf spot, net blotch, stripe rust, and stem rust. Along with grasshoppers and crickets, and other common pests, this family battles crane flies, stinkbugs, and wireworms. Also, aphids may carry a viral disease called barley yellow dwarf. Your average lawn grass has a root system that only goes down a few inches. Other grass plants have roots that can go down 5-10’ or more. So, how about making a little room for a patch of grain? As a food crop, I expect that it will be much like endive, nasturtiums, lentils, and tomatoes—it will continue to turn up long after I have stopped planting it. The grain and grass family provides 51% of all human dietary energy. How much space does it get in your garden?
There are four predatory stink bugs found in the U.S., mostly in southern states. Anchor stink bugs Anchor stink bugs (Stiretrus anchorago) are from Central and North America. They occur in several different color variations, ranging from black, white, and tan, to orange or red and black, to green and yellow.
Florida predatory stink bugs Found predominantly in the southeastern U.S., Florida predatory stink bugs (Euthyrhynchus floridanus) hunt grasshoppers and other garden pests. They go after these larger insects by hunting in packs of up to twelve individuals. These bugs are just under ¾” long and bluish-black or purplish-brown with red rear ends with black markings, though they also come in a variety of colors. They have sturdier snouts than their sap-sucking cousins.
Giant strong-nosed stink bugs The giant strong-nosed stink bug (Alcaeorrhynchus grandis) is found in South and Central America as well as in southern U.S. states. These bugs can be nearly 1” long and they have two distinct points on their backs. They tend to be variegated brown with dark bands on their legs and dark spots on their bellies. Some individuals are red with black leg bands. Unlike the smaller egg clusters of other stink bugs, the giants lay eggs in masses of 100-200 eggs. Nymphs have a bluish-black thorax and red abdomens with dark stripes.  Giant strong-nosed stink bug (Clinton & Charles Robertson) CC BY-SA 2.0 Spined soldier bugs Spined soldier bugs (Podisus maculiventris) are found throughout North America. They prefer feeding on the larvae of cabbage loopers, Colorado potato beetles, diamondback moth caterpillars, European corn borers, flea beetles, gypsy moths, imported cabbageworm larvae, Mexican bean beetles, and velveteen caterpillars, so count yourself lucky if you have these hunters in your landscape. You can even buy spined soldier bugs eggs to add to your IPM program.
As you search your garden for stink bugs, with a bucket of soapy water in hand, keep in mind that not all of them are bad. Sorting between beneficial and pest stink bugs is made a little easier because many predators tend to be more brightly colored and patterned.
Which types of stink bugs have you seen? Red-shouldered stink bugs may invade your home as well as your garden. Red-shouldered stink bugs (Thyanta custator) use their piercing mouthparts to suck the juices from your almonds, apples, beans, corn, peaches, pears, pistachios, tomatoes, and wheat. Their feeding can cause cat-facing and corky fruit, as well as provide points of entry for other pests and diseases. And, of course, they poop on those crops, too.  Red-shouldered stink bug (Russ Ottens, University of Georgia, Bugwood.org) CC BY 3.0 Red-shouldered stink bug identification Adult red-shouldered stink bugs are primarily green but can be brown, with a pinkish edge along the scutellum (just behind the head). That pink edge can be very dark and noticeable, barely present, or missing entirely. They have long antennae (for a stink bug) and, if you flip them over, you will see some of them have black spots on the abdomen.
Nymphs are brownish, with tribal-like designs on their backs. Adults and nymphs average 1/3” in length. Eggs are grey, round to barrel-shaped, and flat on top. Red-shouldered stink bug lifecycle Tiny eggs are generally laid in clusters on plant stems and the underside of leaves. When those eggs hatch, nymphs start feeding on developing seeds and young leaves, buds, and flowers. As they mature, their diet expands to include all those crops mentioned earlier. Then, as temperatures begin to drop, they start looking for a place to overwinter. That winter wonderland may be in mulch, plant debris, or your living room.  Red-shouldered stink bug eggs and nymphs (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0 Similar to ladybugs, red-shouldered stink bugs are notorious for invading homes in autumn. And don’t try vacuuming them up or your vacuum will stink. Instead, invert a plastic bag over your hand, pick those little suckers up, and drop them into a container of soapy water. The same method works outside in the garden, as well.
Stink bugs can smell pretty bad. Even my hens turn up their beaks when one crawls by, so it’s up to you! |
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