The leaves of a healthy blueberry plant are green. The same cannot be said of bushes infected with the blueberry shoestring virus (BBSSV). This disease is common to the upper and northeastern Midwest, but it is also found in Oregon, North Carolina, Washington, and New Brunswick, Canada, and is expected to spread.
Both lowbush (Vaccinium angustifolium) and highbush blueberries (V. corymbosum) are susceptible to the blueberry shoestring virus.
Blueberry shoestring virus symptoms
The leaves and stems of a plant infected with the blueberry shoestring virus are red and deformed. Young stems may show red streaking and leaves become significantly thinner than normal, hence the name. Ultimately, leaves become crescent-shaped and fruit production is all but eliminated.
Other symptoms of blueberry shoestring virus include an oak-leaf pattern of red surrounding leaf veins, flowers of infected plants tend to be pinkish-purple, rather than white, and discolored berries do not turn blue.
Blueberry shoestring virus lifecycle
The blueberry shoestring virus may take up to 4 years to start expressing itself. This allows the disease to spread silently as aphid vectors move from plant to plant, feeding and infecting. Since this disease is spread by aphids, monitoring for and controlling these pests is the best way to keep your blueberry plants healthy.
Infected aphids spread the disease as they feed. They also lay eggs at the base of blueberry buds where they overwinter. As spring temperatures begin to rise, the eggs hatch, and a new generation of infected aphids continues the problem. These eggs tend to hatch when temperatures reach 38°F, so that’s when you need to start treating blueberry plants for aphids.
Blueberry shoestring virus management
Natural predators, such as ladybugs, especially seven-spotted lady beetles, and parasitic wasps provide significant protection against aphid-borne diseases, so avoid using broad-spectrum pesticides. Also, starting with certified pest- and disease-free plants is always a good idea. Infected plants should be bagged and removed immediately. There is no cure for the blueberry shoestring virus.
To protect your plants against the blueberry shoestring virus, do your best to keep aphids under control.
If the tips of your blueberry stems suddenly start wilting, it’s probably blueberry tip borers. Blueberry tip borers (Hendecaneura shawiana) are the larvae of moths. These are not the same thing as blueberry stem borers (Oberea myops), which are a type of beetle.
Blueberry tip borer description
I couldn’t find photos that I could use, but these mottled brown moths look like they have a white saddle and their antennae tend to be long and thin. If you get your hands on one, you may be able to see that they have orange marks near the tips of their wings and a one-half-inch wingspan. The larvae are somewhat yellowish and the eggs are translucent.
Blueberry tip borer lifecycle
Eggs are laid on the underside of leaves. Once they hatch, larvae burrow into canes, usually within half an inch from the tip of the shoot. These larvae feed all summer while inside the plant and then overwinter in their protected space, before pupating in spring.
Managing blueberry tip borers
If new shoots suddenly start wilting, take a closer look. You may be able to see tiny pinhole entries. Tunneling and feeding by blueberry tip borers result in stem wilting and leaf browning, especially around leaf edges.
If you suspect blueberry tip borers, remove an affected shoot and cut it open lengthwise. If you see borer larvae, it’s a good idea to prune out any infested shoots. If you can catch the larvae between hatching and boring, you can apply Bacillus thuringiensis (Bt). Once inside a plant, these pests are pretty safe from whatever you might want to spray.
Like most other blueberry pests and diseases, this one is still mostly found on the East Coast. As more people around the world start growing blueberry varieties that need fewer chill hours, those problems will also spread, so be forewarned.
Blueberry stunt disease is caused by phytoplasmas carried around by sharp-nosed leafhoppers. Phytoplasmas are cell parasites.
Symptoms of blueberry stunt
It should come as no surprise that stunting is the most common symptom of this disease. Closer inspection shows that infected stems have much smaller internodes [spaces between nodes] than healthy stems, which makes the plants look smaller than normal. Leaves may be cupped slightly downward and chlorotic leaf margins may be present.
Blueberry stunt disease cycle
As carrier sharp-nosed leafhoppers feed on blueberry plants, they allow stunt phytoplasmas to move from their host’s gut to your plants. Once inside a plant, these tiny beasties move to the sapwood, where they feed on sap, live, and reproduce.
Blueberry stunt control
Starting with certified disease-free rootstock is one way to reduce the odds of bringing blueberry stunt disease into your garden. Also, use yellow sticky sheets to monitor for signs of sharp-nosed leafhoppers and start treatments as soon as they are seen. Once a plant is infected with blueberry stunt disease, it must be removed and destroyed.
Luckily, so far anyway, blueberry stunt is only found on the East Coast. For now.
Blueberry leaf mottle, affectionately known as BLMV, is a type of Nepovirus. Most Nepoviruses are transmitted by nematodes, but not this one. [I was unable to find a usable photo of blueberry leaf mottle, but this image is close.]
Unfortunately, this disease is spread by honey bees as they collect pollen. It can also be seed-borne, though this is rare. As far as I could learn, blueberry leaf mottle is currently only found in Michigan, Canada, and South Korea. Of course, things can change in a single day. Case in point, this virus has decided that blueberries are no longer their only host. Grapes are now on the menu.
Blueberry leaf mottle symptoms
True to its name, leaf mottling is the primary symptom of blueberry leaf mottle. Infected leaves are often lighter in color and smaller than healthy leaves and may be puckered or otherwise deformed. Stunting and dieback may also occur. Infected grapevines exhibit delayed budbreak, elongated fruits, and sparse fruit clusters.
How to manage blueberry leaf mottle
The kicker about this disease is that symptoms don’t appear until three or four years after the plant is infected. And there are no known treatments. This makes prevention your only option. To prevent blueberry leaf mottle from occurring in your garden, be sure to only buy certified disease-free rootstock. Infected plants must be removed and thrown in the garbage.
I hope your blueberry bushes stay healthy and productive.
You may not be able to see blueberry bud mites, but they can be devastating to your blueberry and huckleberry plants.
Blueberry bushes start producing next year’s fruiting buds as soon as the harvest is over. This is when blueberry bud mites (Acalitus vaccinii) begin causing problems in some blueberry varieties. Bushes that ripen early in the season are the most likely to develop blueberry bud mite infestations.
Blueberry bud mite damage
Poor growth and low fruit set are the first signs of a blueberry bud mite infestation. This damage is first seen around the tops of plants. If you look closely, you may be able to see blistering on bud scales. This blistering is caused by mite feeding. Later in the growing season, deformed flowers, smaller leaves and fruit, and fewer berries per cluster may also be seen. Berries may also be deformed or appear roughened.
Blueberry bud mite identification
If you have a microscope, you can see that these tiny mites are white. Unlike most other arthropods, which tend to have four pairs of front legs, blueberry mud mites have only two. Eggs are clear and spherical. Since these pests are so small, you are probably better off bringing shoot samples to your local Master Gardeners or County Extension Office for identification.
Blueberry bud mite control
Because these pests are so small and tend to stay hidden, they can be difficult to manage. Eggs are laid within the buds, and the nymphs feed on their host buds once they hatch. As buds open, those nymphs crawl up stems where they feed on young shoots.
Commercial growers apply miticides directly after harvesting when blueberry bud mites are detected. Once buds have formed completely, the mites are safe from chemical treatments. Many of the miticides used against blueberry bud mites are not available to home growers. Those that are available require careful timing. Other options include pruning infested shoots and tossing those shoots in the garbage. Predatory mites and predatory thrips provide a little protection, so avoid using broad-spectrum pesticides and plant a few insectaries near your blueberries.
Blueberry bud mites are currently only found east of the Rocky Mountains, but that can always change as more people grow blueberries and huckleberries on the West Coast.
This post is not about watering those weeds, though pot irrigation could be used to do just that. Pot irrigation, also known as pitcher irrigation, is an old method of watering plants regaining popularity, especially in arid regions. It is a convenient way to conserve water while keeping your plants happy and healthy.
plant-food.htmlUnlike gravity watering systems that use inverted bottles that drain into the soil, pot irrigation uses moisture tension to irrigate plants.
What is an irrigation pot?
Irrigation pots are unglazed clay jugs that have been buried in the soil with only the upper edges above the soil line and covered with a ceramic lid or plugged with a cork. Water can seep through these unglazed pots. If the soil is already wet, the water stays in the pot. If the soil is dry, plant roots and the soil pull water from the jug, providing a steady source of water. Over time, plant roots will grow toward and wrap around the irrigation pot.
History of irrigation pots
Irrigation pots or “ollas” have been used for thousands of years. Archeologists have found them around the world, from South America to China. I can imagine that carrying water every day was quite a chore. Being able to fill irrigation pots every few days instead of watering daily would be a big attraction. In fact, I wish I had heard about pot irrigation while I still had my raised beds! I would’ve put one pot right in the middle of each 4x6 bed and saved myself a lot of time and water.
How to use ollas
Inexpensive unglazed ceramic jugs and pots are often available at yard sales and thrift stores. They can be a bit pricey in retail stores, but you have to ask yourself what your time and water are worth. You can also use standard ceramic planter pots. Simply plug the drainage hole with a cork and use the saucer as a lid. If you want to, you could create a system of connected ollas. But that’s beyond this post.
Ollas can be filled every few days, depending on the weather and the size of your irrigation pot. Put simply, bigger pots need to be filled less often, will water larger areas, and take up more space. Generally speaking, a 3-gallon pot will water a three-foot diameter area for 3 to 7 days. In 2013, Ecology Action used five 5-gallon ollas for a 100-square-foot garden plot. Their ollas had caps that reduce evaporation and collect rain.
The important thing to keep in mind when using ollas is that they water the subsoil. Seeds and new transplants will need extra water at the surface to get established. Also, plants should be installed at least one foot away from the olla to keep young roots out of the heavily saturated soil.
Benefits of pot irrigation
Pot irrigation is said to conserve 50% to 70% of your irrigation water. That’s a lot of water! Watering from the soil also significantly reduces fungal diseases and you don’t have to mess with the garden hose as often. You can also add fertilizer to your olla, allowing plant roots to absorb those nutrients at a gentle pace while preventing up to 66% nutrient loss due to evaporation and inaccessibility. Finally, clay pots are earth-friendly. There are no plastics or chemicals to leach into your soil or food supply. You may have to monitor for slugs, however.
The way ants walk around has always struck me as pretty random. Until there’s a chemical trail to follow, of course. But now there’s a new type of ant that walks around frantically, like some sort of manic crackhead.
These ants are tiny, less than one-eighth of an inch long, but they can do damage. While these ants do not have stingers, they do bite. And they carry venom that they deposit into bites. Crazy ant aphid-farming has led to the devastation of grasslands. They commonly torment larger livestock by attacking around the eyes and nose and have been known to suffocate chickens. They will also attack your computer.
For some bizarre reason, crazy ants are attracted to electronic equipment where they are often electrocuted. When electrocuted, they release a pheromone. This pheromone tells their fellow crazy ants they are under attack. Other ants come to the rescue and are also electrocuted. This releases more pheromones. Before you know it, the electrical system shorts out because of all the dead ants.
There are several types of crazy ants. We will take a look at the black, tawny, and yellow crazy ants.
Black crazy ants
Southeast Asian black crazy ants (Paratrechina longicornis) are also known as longhorn crazy ants because of their long, segmented antennae. They are dark brown to black and may have a bluish tint. These ants have very long legs.
Tawny crazy ants
Tawny crazy ants (Nylanderia fulva) are also known as rasberry ants. That isn’t a typo. An exterminator from Texas, Tom Rasberry, identified these South American invasive pests in 2002. Tawny crazy ants are reddish-brown and have a few long, coarse hairs. Males and females both have wings, but females shed their wings after mating.
Yellow crazy ants
Believed to be from Africa, yellow crazy ants (Anoplolepis gracilipes) have the dubious distinction of being listed as one of the world’s 100 worst invaders by the ISSG. These pests kill and pester a wide range of mammals, birds, reptiles, and beneficial insects. These slightly larger crazy ants are 4-5 mm long. Like tawny crazy ants, they have long, jointed antennae and long legs, but they are yellowish-brown to reddish-brown with big eyes.
Crazy ant lifecycle
Crazy ants are not as well-organized as other ant species. Instead of building nests, they live in piles of plant debris, tree cavities, under rocks, and in electrical equipment. Very often, as temperatures drop, these pests move indoors and into your stereo. Instead of a single queen lording over her countless minions, crazy ant colonies tend to be small with several queens. As many as 20 queens may be hiding under a rock. And these single colonies network with neighbors. A single collection of a few hundred crazy ants can quickly become a “supercolony” of hundreds of millions of ants.
These crazy ants search far and wide for food. They do it quickly, and they eat pretty much anything: living or dead insects, nectar, honeydew, seeds, plants, grease, and sugar are just a few of the snacks these pests will bring home for the colony.
Crazy ant control
First found only in southern states, these pests have moved northward to Massachusetts and west to California and Hawaii. Controlling crazy ants is difficult because of their networked colonies. Standard ant baits and over-the-counter pesticides do not work against crazy ants.
If your house, garden, or vehicle are infested with crazy ants, call a professional exterminator. In 2008, the Environmental Protection Agency authorized the use of fipronil against these pests. Unfortunately, fipronil is considered one of the worst causes of colony collapse disorder in honey bees. It’s best to leave those treatments to the pros.
Stump stabbers may look dangerous but these beneficial insects lay their eggs in pests.
Like other ichneumon wasps, stump stabbers (Megarhyssa macrurus) help in the fight against garden and landscape pests. Also known as giant ichneumon wasps, their giant stingers are egg-laying organs called ovipositors.
Stump stabber description
Females can be 2” long, reddish-brown with black and orange or white stripes, with an ovipositor that can be 4” long. What looks like a single strand is actually three parts. Two interlocking strands have cutting tips, and a third strand is a tube that transports the eggs to where they need to go. Males are only one-quarter that size and they do not have an ovipositor or a stinger.
Stump stabber behavior
Instead of threatening your picnic lunch, female stump stabbers fly from tree trunk to tree trunk, waving their antennae and running around on the bark. They are listening closely for the sound of pigeon horntail and other wood wasp larvae. Wood wasp larvae chew their way through any decaying wood that may be present in your deciduous trees. Mother stump stabbers use their impressive ovipositors to pierce tree bark and lay their eggs on the pesky larvae. When the eggs hatch, they eat their host and then pupate for the winter.
You may see male stump stabbers running around and flying around in a similar way, but they are looking for mates, not food.
Of course, if you happen to see anything burrowing into your trees, you need to take a closer look. It may be that your tree needs a helping hand.
Asian giant hornets are huge bee murderers with powerful stings, and they have reached North America.
Asian giant hornets (Vespa mandarinia) are the biggest hornets in the world. Native to Asia, these pests have been identified in Washington State since 2019 and several other potential sightings have prompted quarantines and requests to the public to be on the lookout.
These hornets have stingers that are twice as long as honey bee stingers and they contain a lot of venom. They can also spray venom into your eyes. Being stung by several of these monsters at the same time can kill you.
Asian giant hornet identification
Asian giant hornets have a 3” wingspan. The queen averages just under 2” in length while the workers and drones are slightly smaller. Their heads and forelegs are pale orange with a brown base. The body has alternating brown or black and orange bands.
Asian giant hornets are commonly misidentified as European hornets (V. crabro) and Eastern cicada killers (Sphecius speciosus) in the U.S., and Oriental hornets (V. orientalis) and Asian hornets (V. velutina) in Europe.
Asian giant hornet lifecycle
Asian giant hornets are most commonly found in forests and hilly areas. They feed on large insects, tree sap, and honey bees. Mostly honey bees. A group of Asian giant hornets can kill an entire colony of honey bees in just a few hours. Your average honey bee colony contains tens of thousands of bees.
Asian giant hornets use vision, sound, and chemicals to communicate. They are the only hornets that use scent markers to guide the colony to food sources. Sadly, honey bees are their most common food source. But a single hornet cannot attack a honey bee hive. The bees will surround the hornet and use their wings to generate so much heat and carbon dioxide that it kills the hornet. In most cases, however, these hornets attack hives in concert.
They build their nests in tree cavities, around rotting tree roots, and in rodent and snake holes. These holes can be 6” to 24” deep. The comb is formed into towers that can be 18” tall and wide. Old towers are abandoned and left to rot, and new towers are built alongside the old ones.
Reproduction and castes are similar to honey bees, except that Asian giant hornet hives may contain dozens or even hundreds of queens. The highest-ranked queen gets first dibs on any available sap, followed in ranking order by other queens. Drones provide semen and workers collect food. They also fiercely protect whatever they consider theirs.
Mated queens go in search of new nesting sites in mid-spring. Once a site is found, she creates a small hive where she will lay 40 or so worker eggs. These workers emerge in mid-summer. By this time, the hive is likely to have 500 cells and 100 workers. This is when unmated queens disappear. By the end of summer, cells are filled with eggs. When the eggs hatch, Asian giant hornet larvae tells their caregivers it’s dinner time by scraping their mandible against cell walls. When they have eaten their fill, they spin cocoons around themselves.
Reporting Asian giant hornets
If you live in Washington State and see an Asian giant hornet, please report it to the Washington State Department of Agriculture (WSDA) immediately. Otherwise, contact your local Extension Office. And you may want to invest in one of Dennis Jaffré’s new Asian giant hornet traps.
Once you have grown your own food, groceries take on a whole new category of appreciation.
Everyone talks about how homegrown tomatoes taste so much better than store-bought, which they do, but it’s more than that. Moving to an apartment and still living under the threat of Covid, a recent grocery delivery showed me just how much my perspective on food has changed, being a gardener.
So many people and steps were involved with something that used to grow freely in my yard. This is true of every food we eat that we do not grow at home. And I am grateful to all those people.
Have I planted cilantro seeds in a pot on my balcony? I have. But that isn’t always an option.
I cut open the last Valencia orange from my California home to use while cooking some black beans a couple of nights ago. I had to take a bite. It was so sweet and delicious! It made me a little sad to have left so much behind. Will a store-bought orange ever taste so good? It will certainly never be as fresh.
Can I grow oranges in my Seattle apartment? I don’t know yet. But I will find out. And I will love being closer to my children and grandchildren as I learn.
Silver leaf may inspire memories of your great-grandmother’s tea service, but this fungal disease is anything but elegant.
Silvering leaves spread throughout an infected tree and can lead to tree death. Caused by the
Chondrostereum purpureum pathogen, this disease infects many members of the rose family (Rosaceae) but is found most commonly among apples and pears, plums, and other stone fruits. It can also occur on alder, beech, birch, buckeye, hawthorn, larch, maple, poplar, spruce, and willow, so these trees should be monitored for the disease, as well as rhododendron.
Silver leaf symptoms
The leaves of affected limbs slowly turn silver, or bleached. That silvering is the result of toxins released into the vascular bundle and carried to the leaves. [I was unable to find a photo I could use, but you can Google it.] These symptoms spread progressively throughout the tree, killing branches as it goes. Infected wood is darker than normal. A whitish crusty area may also be seen on the bark. This is the actual fungus. If you look closely, you may notice the edges are purple. The body of the crust feels rubbery and may be covered with white hairs. After the fungal bodies have fruited, this crust turns beige or brown.
Leaf silvering can also occur as a result of environmental stresses, such as drought or cold. This is called false silver leaf. If you cut into a limb affected by false silver leaf, the interior wood will be a normal color and not stained. Leaf symptoms may also be caused by whitefly feeding.
Spores float on cool, moist breezes. When they land on freshly exposed sapwood, the infection begins. That sapwood may have been exposed due to pruning, herbivore damage, a playful child, or too much fruit.
Silver leaf management
Trees infected with silver leaf often die. There are steps you can take to prevent it from occurring in the first place. One method is to prune susceptible trees, especially cherries and plums, in summer. Rather than painting the surface of pruning cuts, allow them to heal naturally. Too often, sealants keep the wound from drying, which results in rots and other fungal diseases. And be sure to thin fruit to the point that branches aren't overburdened.
If an infection occurs, cut off the affected limb at a point 6” below the infection, sanitizing your cutting tool with bathroom cleaner between each cut. Infected wood should be bagged and tossed in the trash right away, as it is a source of further infection. Continue to monitor the tree closely for symptoms.
Scabby knees and elbows may be a normal part of childhood, but it’s not what you want to see on your potatoes or other root vegetables.
Unlike apple scab, which is a fungal disease of fruits, common scab is a bacterial disease that prefers life underground. The actinobacteria responsible for common scab, Streptomyces, are found everywhere. Most commonly occurring in potatoes, beets, carrots, parsnips, radishes, rutabagas, and turnips may also become infected with common scab.
Common scab symptoms
Common scab looks exactly how it sounds. Surface russeting is the first thing you notice about plants with common scab. If you look deeper, you will also see deep pits in your tubers and root vegetables. Luckily, infected plants are safe to eat. Simply cut away the bad bits and toss them into the compost pile.
Common scab lifecycle
Common scab bacteria overwinter in infected roots and tubers left in the soil. Bacteria can also be spread via wind and rain splashing. Bacteria enter roots and tubers through natural openings, such as stoma, and wounds from insect feeding and shovels. The infection starts on the surface and works its way inward. These bacteria feed on the roots and tubers and will continue to reproduce for as long as temperatures are warm enough.
Common scab management
Common scab occurs most often in dry soils. This means that regular irrigation goes a long way toward preventing common scab in root vegetables. Common scab is more likely in soils with a pH greater than 5.2, so acidifying alkaline soils may also help prevent scabbing. Finally, rotate your potatoes and other root crops with non-tubers and watch for resistant cultivars when shopping for seeds and seedlings.
Aster leafhoppers are also known as six-spotted leafhoppers, but you’re unlikely to see those spots without a hand lens.
Like other leafhoppers, these insects are fast. They hide under leaves and jump away when disturbed. It may seem easier to just ignore these tiny sap suckers, but aster leafhoppers (Macrosteles quadrilineatus) are vectors for aster yellows disease.
Aster leafhopper damage
As aster leafhoppers feed, they often spread aster yellows disease. Aster yellows is a bacterial disease of carrots, celery, dill, lettuce, oats, onion, potato, radish, rye, and sunflowers. Several ornamentals, such as coneflower, may also become infected. The first symptoms of aster yellows are yellowing veins and leaves that may become twisted, and distorted, sterile flowers. But carrying disease isn’t the only damage caused by aster leafhoppers.
Aster leafhoppers use piercing mouthparts to suck plant juices from leaves and stems. This gives plants a bleached, stippled appearance and it puts a serious dent in a plant’s ability to perform photosynthesis. It also creates points of entry for several other pests and diseases. Adding insult to injury, their excrement creates a habitat for sooty mold.
Aster leafhopper identification
Aster leafhoppers are very small, averaging less than 1/5” in length. They are wedge-shaped and olive green. If you look closely, you will see that the abdomen is yellowish-green and the forewings are grayish-green. If you could hold one still and look through a hand lens, you might be able to see the three pairs of black spots on the head. Wings are transparent. Nymphs look like miniature adults, but they are cream-colored or dark green and they lack wings.
Aster leafhopper lifecycle
These pests blow in on strong winds, usually coming out of the south. Eggs are quickly inserted under the leaf epidermis of host plants and assorted weeds. Eggs hatch in only a week and their lifecycle only lasts four weeks. During that time, they are eating and spreading disease.
Aster leafhopper management
Aster leafhoppers often hide out in weeds such as dandelion, horseweed, pineapple weed, Queen Anne’s lace, and ragweed, so keeping those weeds away from your garden may help. Yellow sticky sheets can be used to attract and capture these and other pests. As always, remove any plants infected with aster yellows disease and toss them in the trash.
Horticultural oil, neem oil, or insecticidal soap can also be used against aster leafhoppers, but they are only effective if the pest is coated with the stuff, which is difficult to do. They tend to move away rather quickly when sprayed. What you can do is use row covers to protect plants from aster leafhoppers. Reflective mulch has been shown to repel leafhoppers.
I hope that aster leafhoppers never blow into your landscape.
Tarnished plant bugs feed on more than half of our garden crops, using their piercing mouthparts to suck the life from beans, stone fruits, strawberries, and other edibles. While these pests were once only found east of the Rocky Mountains, they now occur throughout North America.
Tarnished plant bug damage
Tarnished plant bugs (Lygus lineolaris) eat all aboveground parts of a plant. They feed by injecting saliva into host plants. This saliva breaks down the pectin and plant tissues, making it possible to suck up their meal. As they feed, they cause distorted and discolored fruit and pod lesions. You may also see growing tips that are distorted, have lesions, or are dying back. Affected flowers tend to be distorted, discolored, or have signs of blight. These pests are responsible for blossom drop of tomatoes and peppers. Seeds may be distorted or shriveled. And the entire plant may show signs of dwarfing or rosetting due to tarnished plant bugs
Tarnished plant bug lifecycle
Tarnished plant bugs overwinter as adults in weeds and fruit trees. Females prefer laying their eggs in cotton plants, but they will make do with what’s available. These eggs are laid in mid-spring and hatch in early summer. Populations tend to peak when eggs hatch and again in mid-autumn.
Tarnished plant bug management
These pests like to hide in nearby weeds, so lose the weeds and mulch those areas with free wood chips from your local arborist. Tarnished plant bugs have several natural enemies. One nursery web spider, Pisaurina mira, loves to feed on tarnished plant bugs, so avoid those broad-spectrum pesticides.
While pesticides are commonly used against juvenile tarnished plant bugs in commercially grown crops, the effectiveness of those chemicals is decreasing. Pesticides don’t work well on adult tarnished plant bugs, to begin with. Research has shown that these pests are attracted to pink sticky paper, so that’s an easy organic control method. Certain parasitic wasps also play a role in controlling tarnished plant bug populations. A strong spray from the hose can dislodge juveniles, who are often unable to find their way back to a host plant.
Be on the lookout for these pests the next time you’re weeding around your fruit trees or garden plants.
A perfectly healthy plant takes a sudden turn for the worse. It wilts. It shrinks. It changes color. It looks starved. It might be infected with root-knot nematodes
Root-knot nematodes (Meloidogyne spp.) are plant parasites that thrive in regions with hot summers and short winters, causing problems in over 2,000 different plants. They will infect everything in your garden except onions and corn. And I don't know why scientists say plants are infected with nematodes instead of infested, but they do and so will we.
The only way to tell if a plant is infected with root-knot nematodes is to dig it up. Before we do that, let’s see what we’re up against.
What are nematodes?
Nematodes are microscopic, unsegmented worms. Some of them are beneficial and some carry disease. Beneficial nematodes kill cutworms and corn earworm larvae. Disease-carrying nematodes include needle nematodes, stubby root nematodes, and root-knot nematodes. The real problem with nematodes is that there are so many of them. It is estimated that, for every person on earth, there are 60 billion nematodes. [Thank goodness they aren’t all bad!]
Root-knot nematode lifecycle and damage
There are over 90 different types of root-knot nematodes and they are found worldwide. Females lay eggs in roots. Those eggs hatch into juveniles that go through several molts. During that time, they may stay in their mother’s plant or go find their own.
Root-knot nematode larvae infect plant roots, causing galls to form. Galls are swellings that occur in response to invasion. Galls caused by bacterial or fungal infection contain bacteria or fungi, respectively. Galls caused by root-knot nematode larvae contain only plant tissue. These goals interfere with the uptake of water and nutrients, so young plants starve to death, and older plants struggle. Those struggling plants are more susceptible to other pests and diseases, as well as environmental stresses, such as drought or unhealthy soil.
If that weren’t bad enough, root-knot nematodes can also carry Aster yellows phytoplasma. That’s the disease that gives you fuzzy carrots and damages your caraway, celery, cilantro, and lettuce.
Root-knot nematode management
Commercial growers use chemicals called nematicides to combat root-knot nematodes. Many of those chemicals have been banned because of the harm they cause. Luckily, there are organic methods of controlling root-knot nematodes. The prettiest way is to grow Tagetes marigolds. The roots of these lovely flowers put out chemicals that suppress these pests. But you have to plant a lot of them. Pretty rows won’t cut it. And not all Tagetes species are effective. Avoid using signet marigolds (T. signata or tenuifolia) because these attract and feed nematodes.
Maintaining healthy soil is one of your best defenses against root-knot nematodes because microorganisms compete with each other. Healthy soil contains a lot of microorganisms that will compete with these and other pests. Mulching and top dressing with aged manure and compost feeds those helpful microorganisms.
You can install resistant plant varieties, making sure to buy certified disease-free seeds and seedlings. Crop rotation and allowing planting areas to go fallow every few years will help keep nematode populations in check. And plant some of those lovely marigolds!
Malabar spinach is native to tropical Asia, so hot weather isn’t a problem. Unlike regular spinach, which bolts as soon as temperatures begin to rise, Malabar spinach grows best in summer. Malabar spinach isn’t a type of spinach. Instead, it is a distant cousin to amaranth, beets, cacti, and ice plants
Also known as Indian spinach and vine spinach, Malabar spinach contains high levels of vitamins A and C, calcium, iron, potassium, magnesium, and manganese, and lots of soluble fiber. Young leaves are often used in salads. Crisp and juicy, they are said to taste like a cross between citrus and sweet peppers. Older leaves, which taste more like spinach, are steamed or boiled. Cooked Malabar spinach has a mouth-feel similar to okra. As such, Malabar spinach acts as a thickening agent in stews and other dishes. The flowers are edible, too.
How to grow Malabar spinach
These plants grow best in loose, nutrient-rich soil with a pH of 5.5 to 8.0 and good drainage. Seeds, cuttings, and transplants can be started in early spring in a protected location. Seeds should be planted 1” deep. Once temperatures have warmed, move your Malabar spinach plant to a cattle panel, fence, or trellis. Plants should be spaced two feet apart.
As tropical plants, Malabar spinach needs consistent moisture. Water deeply and mulch around the plants to hold that moisture in place. You can grow Malabar spinach in partial shade, but it prefers full sun.
Malabar spinach pests and diseases
Malabar spinach has few problems for the home gardener. Leaf miners, root-knot nematodes, and tarnished plant bugs may cause feeding damage. Rotating Malabar spinach with amaranth or corn may minimize damage caused by root-knot nematodes. Fungal leaf spot diseases may also occur.
As productive and trouble-free as Malabar spinach is, you may want to give it a try in your garden.
The tomato mottle mosaic virus was first identified in 2013 in Mexico. It is now found around the world, and it threatens your tomato and pepper plants.
This disease is still relatively rare, but scientists believe that it may be able to infect members of the cabbage family and other members of the nightshade family. They are still sorting out all the details.
As such, there aren’t any good photos of this disease available yet. Tomato mottle mosaic virus (ToMMV) is a close relation to tomato mosaic virus and tobacco mosaic virus, so I’ve included photos of those diseases to give you an idea of what we’re up against
Tomato mottle mosaic virus symptoms
Symptoms of tomato mottle mosaic virus include:
Without flowers, there is no fruit. These symptoms spread rapidly and the disease is highly contagious.
Tomato mottle mosaic virus management
Scientists believe that ToMMV spreads through plant-to-plant contact, as well as on contaminated clothing and tools. Pollinators, contaminated irrigation water, and infected seeds may also help spread this disease. There are no resistant plant varieties. Some studies have shown that this particular virus can break the resistance of our garden plants to tomato mosaic virus and tobacco mosaic virus. This ability has farmers worried, and with good reason.
There are no known treatments against tomato mottle mosaic virus (yet), so prevention is the best course of action. This means:
If you suspect tomato mottle mosaic virus in your garden, collect a sample and contact your local County Extension Office or Department of Agriculture. Working together, we can help slow the spread of this and other plant diseases.
Some plants, such as lettuce and broccoli, need a lot of water. Succulents and herbs need far less water. If these plants are grown together, somebody is getting too much, or somebody isn’t getting enough. Hydrozoning refers to the practice of growing plants with similar water needs together.
Benefits of hydrozoning
Grouping plants with similar water needs makes your job as a gardener easier. Areas that need lots of water get more attention, while areas needing less water can be irrigated less often. This practice conserves water resources. More importantly, it keeps plants healthier and less prone to pests or diseases.
Overwatering and underwatering both set the stage for problems in the garden. With mixed water use plantings, some plants are getting the wrong amount of water. By grouping plants according to their water needs, you can provide exactly the right amount of water in each planting area, and everyone is better off.
Designing for hydrozoning
The easiest way to design your hydrozones is to put plants that need the least amount of water furthest from your water source while placing plants that need more water closer to your hose spigot. Of course, for perennials that are already in place, this isn’t an option. But you can still use the hydrozoning concept. For example, I have several fruit trees in my yard. Each tree has an irrigation ring around it. These trees can use a lot of water in summer. I also grow a fair number of tomato plants. I have found that it simplifies everything, irrigation-wise, to grow my tomatoes around my trees. That way, I put water in the irrigation rings and both types of plants thrive. My potato bed, on the other hand, is at the far back of my yard. Since potatoes rot when overwatered, making it a little less likely benefits me and my plants. You will probably find that crop rotation puts your planting beds closer to or further from your water source from year to year, but you get the idea.
Which plants go into which hydrozones?
Each garden is unique, but we can make some generalizations about which plants have similar water needs. And those water needs are not simply about irrigation. Rooting depth is another factor. Some plants have shallow root systems that need frequent watering in summer. Other plants have deep roots that allow them to collect some water for themselves. And those water needs will change during a plant’s lifetime. Creating fruit or seeds is hard work for a plant and they need extra water to make those beans, squash, and tomatoes. Even those potatoes need more water when tubers are setting.
Keep in mind that specific cultivars may have different characteristics than the rest of their family when it comes to water needs. Tepary beans thrive in deserts, while other bean species need more frequent watering.
You may have to experiment with hydrozones in your landscape, but that’s okay. It’s one of the joys of gardening, in my opinion. One project or plant may feel like a disaster one year. The next year, it may be a complete success. As you learn more about your soil and the plants you grow, the better able you will be to give them the water and care they need to thrive. Hydrozoning is one way to achieve that goal.
Gummy stem blight is a fungal disease of cucumbers, melons, pumpkins, squash, watermelons, and other cucurbits.
Gummy stem blight (Didymella bryoniae) is responsible for crop losses of up to 30% when it occurs, but there are steps you can take to prevent it. First, you need to know what it looks like.
Gummy stem blight symptoms
Plants infected with gummy stem blight show symptoms on leaves, stems, and fruit. Those symptoms can vary, depending on the host plant, but most of the time leaves develop circular, water-soaked lesions that go from tan to dark brown. These lesions may develop yellow halos. When they dry, they may crack and then fall away. In some species, these lesions are more irregularly shaped. Leaves may also develop dark brown edges.
Infected stems have water-soaked areas that turn tan. In some cases, those areas evolve into dark cankers that may contain fruiting structures that look like black pepper. These fruiting bodies are called pycnidia [pik-NI-dea]. These cankers often discharge a gummy brown ooze, hence the name. That ooze can collect into reddish-brown or black beads, making it easy to confuse this disease with Fusarium wilt. Plants infected with Fusarium wilt won’t have the black pycnidia seen in gummy stem blight. New seedlings infected with gummy stem blight will look as though they absorbed too much water. They are darker than normal, too.
When fruits are infected with this pathogen, the condition is often called black rot. But this is not the bacterial black rot that affects members of the cabbage family. Fruits infected with gummy stem blight often start rotting at the stem end, making it look like an upside-down version of blossom end rot. Fruit can also rot from the inside out.
Gummy stem blight disease cycle
Gummy stem blight spores are common in the environment. This disease is both seed- and soil-borne. To become a problem, there must be enough heat and moisture for fungal spores to germinate. This disease is most likely when temperatures are 68°F to 77°F and humidity levels are above 85%, which explains why this disease is so common in the southeastern states of the US.
Leaves that stay wet for more than one hour provide the moisture needed for spores to germinate and penetrate healthy plant tissue. Spores also enter through plant wounds created by insect feeding, happy dogs, and other garden visitors. Other diseases, such as powdery mildew, can also weaken a plant, making it easy for fungal spores to take hold.
Once it enters a plant, this pathogen moves to the stems, where those cankers begin to form.
Gummy stem blight management
Infected plants should be removed and tossed in the trash bin. Two- or three-year crop rotations, removing plant debris at the end of each growing season, and maintaining proper plant spacing help prevent gummy stem blight. And keep those leaves dry by avoiding overhead watering. While there are no resistant varieties, you can buy seeds treated for gummy stem blight.
Four-lined plant bugs are sap suckers. This means they have piercing mouthparts, similar to their cousins, tarnished plant bugs and capsid bugs. Small populations can be ignored, but things can get out of hand.
Four-lined plant bugs (Poecilocapsus lineatus) are traditionally found east of the Rocky Mountains, but that can always change.
Four-lined plant bug identification
Four-lined plant bugs look like small beetles, but they lack the characteristic hardened wing covers. They are greenish-yellow with four distinct black stripes running the length of their wings. The head is orangish-brown, with prominent red eyes, and they average ¼” long or a little more. Newly hatched nymphs are bright red with black wing pads. If you flip one of those nymphs over, you’ll see black spots on the abdomen. As they mature, nymphs turn more orange, and a stripe develops on the wing pads.
Damage caused by four-lined plant bugs
Adults and nymphs feed on basil, cucumber, currants, gooseberry, lavender, mint, oregano, peppers, and sage. They also suck the vital fluids from several flowers and woody shrubs, including azalea, butterfly bush, dogwood, geraniums, Shasta daisy, and zinnia. As they pierce plant cells and siphon out sugary liquids, dark, round, sunken spots appear. Those spots range from 1/8” to 1/16” in diameter. Those spots may turn black or translucent. After a few weeks, the dead plant tissue falls away, leaving holes in leaves. These holes are commonly mistaken for leaf spot disease. If leaf holes have discolored edges, they are more likely to be bacterial or fungal disease than insect feeding. Distorted growing tips may also occur.
Four-lined plant bug lifecycle
Four-lined plant bug nymphs emerge in late spring and start feeding on the upper side of leaves. One month later, they molt and become adults. Those adults continue eating as they look for a mate. Females then cut 2” vertical slits into stems where they lay six or more banana-shaped eggs. Adult feeding continues through mid-summer. The next spring, those eggs hatch, and the cycle continues.
Four-lined plant bug management
Unless the infestation is severe, you don’t need to do anything about four-lined plant bugs. Monitor your plants for signs of infestation as you work in the garden. Don’t be surprised if one of these pests falls to the ground if you surprise them. They tend to panic that way, even though they can fly. They are also known to try hiding from us behind stems as we pass by. And they move quickly.
If four-lined plant bug infestations become troublesome in your landscape, you can reduce their numbers by removing the aboveground portion of host plants in autumn and tossing them in the compost pile. Composting destroys many eggs before they have a chance to hatch. Treat severe nymph infestations with insecticidal soap or neem oil. These treatments aren’t very effective against adults. I have no idea why.
You can grow a surprising amount of food in your own yard. Ask me how!
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