Your tree may house a tiny, fungi-farming beetle called the polyphagous shot hole borer, but I hope not.
Native to southeast Asia, these invasive beetles are threatening trees in Israel and California with Fusarium dieback. Fusarium dieback is a fungal disease that blocks the flow of water and nutrients through a tree’s vascular system. And polyphagous shot hole beetles actively farm those particular fungi. We will get to that in a minute.
Polyphagous shot hole borer identification
Polyphagous shot hole borers (Euwallacea fornicatus) are smaller than a sesame seed. You could fit 6-10 females, end-to-end, across a dime. Females are black and males are brown and wingless, but you will probably never see a male. Sightings are rare and no wonder. Males stay in the galleries and you could fit 12-18 of them across the face of a dime.
Polyphagous shot hole borers look identical to another invasive borer called the Kuroshio shot hole borer, or tea shot hole borer (Euwallacea fornicatus). The tea shot hole borer prefers tea plants in Sri Lanka, while the polyphagous shot hole borer appears to have a voracious appetite for over 110 tree species. [The word polyphagous means eats many things.]
Host trees and signs of infestation
Traditionally, polyphagous shot hole borers tended to only infest dead or dying trees. Having been accidentally introduced to new regions, these pests have developed a taste for healthy trees. Once trees are infected, they can die. Host trees include:
External symptoms of infestation often look innocuous. Slightly weepy, small damaged areas of the bark, the presence of white frass, maybe a little sawdust or sugar volcano action is all you can see from the outside. If you look very closely, you may see several exit holes, about the size of the tip of a ballpoint pen. The inside of an affected tree is something else entirely.
Polyphagous shot hole borers chew holes that penetrate 1/2” to 1-1/2” into the wood. Then they start burrowing, creating galleries. Black flecks and tunnels can be seen throughout an infested tree. These black areas indicate where Fusarium fungi are being farmed.
Polyphagous shot hole borer as farmers
Polyphagous shot hole borers are a type of ambrosia beetle. Rather than feeding on bark or wood or sap, ambrosia beetles eat fungi that they grow for themselves. Polyphagous shot hole borers have tiny pockets on their exoskeleton. In these pockets, they carry spores of the Fusarium euwallaceae fungi. After burrowing into a tree, the borer starts growing these fungi along the walls of the burrowed galleries. The fungi provide adult and larval forms of polyphagous shot hole borers with food in a protected environment and the borers carry the fungi to new trees. It's a win-win situation for them. The problem is, this fungi causes Fusarium dieback. Fusarium dieback causes branch dieback, canopy loss, and it can kill trees.
Polyphagous shot hole borer management
Yellow sticky cards, purple prism traps, and multiple funnel traps have been used with some success. Because polyphagous shot hole borers have no natural enemies here in California, and because they live inside the tree, safe from insecticides, prevention is worth the effort.
Polyphagous shot hole borers are most commonly spread on firewood. If infested trees are chipped into mulch, the borers can catch a ride to your trees, so always inspect wood chips before accepting them. Wood chips cut into pieces smaller than 1” are generally considered safe because the borers get chopped up too. Personally, if I saw black galleries, I would refuse delivery just in case.
If you suspect polyphagous shot hole borers have found your trees, please contact your local County Extension Office right away.
Conks are woody, shelf-like structures produced by some fungi. These fruiting bodies are often seen on trees and they can indicate fungal diseases, such as canker rot.
Conks are the reproductive form of a large group of fungi known as polypores. Polypores are mostly found in the bark, trunks, and branches of trees, though some are found in the soil. Polypores play major roles in the decomposition of wood, so their presence often indicates decay. Polypores are also important in nutrient cycling, so they aren’t all bad. This is a large, diverse group but they all have conks in common.
The conk clan
This group is defined, not by genetics, but by growth behavior, so it is very diverse. The most common types of conks include:
Also known as bracket fungi, or shelf fungi, this group (Basidiomycota) produces circular, shelf-shaped fruiting bodies that can appear in rows, columns, or singly. Basidiomycetes are the only fungi known to break down lignin. Lignin is what makes trees rigid and hard. The disease that accomplishes this feat is known as white rot.
Some conks are annuals while others are perennials, some of which can live for 80 years or more. In either case, they tend to be tough, leathery, sturdy growths. These growths produce spores, called basidiospore, in pores found on the underside of the conk.
Conks appear to grow directly out of the wood on which the fungi feed. If you were to cut one open and look at it closely, you would see two layers: a tube layer and a supporting layer. The tubes are honeycomb-like structures lined with a spore-forming surface, called the hymenium, and the supporting structure creates the shelf and its attachment to the tree.
The problem with conks is that their presence indicates that some sort of fungi has taken up residence in your tree. If your tree has conks, the first step is to identify the type. Some fungi are worse than others.
Preventing fungal conks
The fungi that produce conks generally enter trees through mechanical wounds, damaged roots, broken or rubbing branches, frost cracks, sunburn damaged bark, and improper pruning. Fungal spores travel on the wind, rain, and on birds and insects, so keeping your tree’s protective outer layer intact is the best prevention. This means you should:
If you have a tree with conks, you should probably contact a certified arborist. They can inspect the tree for structural integrity and to determine the extent of the infection.
Conks may look cool, but you don’t want them on your trees.
Can you see a crack in the trunk or branches of your tree? It may be canker rot.
Canker rot is a collection of fungal diseases that eat away at the interior of tree trunks and branches, weakening the tree and setting the stage for other pests and diseases. Canker rots can also girdle your tree and kill it. While most commonly seen in ornamental trees, canker rot can occur in apple and other fruit and nut trees. Trees with canker rot can be extremely dangerous and should be dealt with right away.
Canker rot identification
Cankers are open wounds, or lesions. Cankers can be a few inches long and wide, or several feet long, depending on the fungal species. The bark next to these cankers dies, becoming discolored, often lighter or orangish, and it is tightly bonded to the canker. After a year or so, the dead inner bark turns black and stringy. This looks a lot like sooty bark canker, but canker rot can also have lenticular (lens-shaped) lighter areas in the bark. Unlike other canker diseases, canker rot affects both bark and inner tissue.
Canker rots can also cause swelling, sunken areas, gnarled bark, and conks. Conks are shelf-shaped fungal fruiting bodies. After spores are released, the conk will dry out and darken. It may remain on the tree or fall off.
If you were to see inside your tree, you would see that the heartwood and sapwood have become discolored. Instead of the warm, rich yellowish-browns of healthy wood, you would see gray, orange, or even pink-tinged wood, often extending 3 or more feet beyond the canker.
Canker rot lifecycle
The fungi responsible for canker rot usually enter trees through pruning cuts and wounds. Fungi attach to the wood and then move to the cambium to access the water and nutrients flowing through the vascular bundle. This is what causes the canker. The fungi also move to the bark, where they eject spores, which are then carried on wind to nearby trees.
How to control canker rot
As always, healthy trees are better able to protect themselves. This means selecting species suitable to your microclimate, planting them at the proper depth, irrigating and fertilizing your trees properly, and monitoring for signs of problems. Other actions you can take to reduce the chance to canker rot occurring in your trees include:
Canker rot can make your tree dangerous. If it is a large tree and the canker is directly facing or opposite the prevailing wind, your tree can be blown over. Large trees weigh several tons and can be extremely dangerous. If you suspect canker rot, call a licensed arborist right away.
Root sprouts appear to be random baby trees or shrubs that keep popping up in your landscape. Getting rid of them can be difficult.
Many plants pass on their genetic information through seeds. Seeds are spread by birds, the wind, people, and herbivores. Plants can also propagate themselves vegetatively using suckers, adventitious shoots and root sprouts. These growths emerge from adventitious buds, which occur close to the vascular bundle, where they will have easy access to water and nutrients. The different names refer to where they occur. Suckers, also known as basal shoots, occur at the base of a tree or shrub. Adventitious shoots can form on stem internodes, leaves, roots, or callus. Root sprouts emerge from the root system.
Root sprout growth
Root sprouts often grow out of adventitious buds found on a tree’s extensive root system. Root sprouts are clones of the parent plant.They can be found a significant distance from the parent tree. Root sprouts can also grow from the roots of a tree that has fallen or been cut down. Apple, cherry, and guava are especially prone to root sprouts.
If a plant produces root sprouts, it is said to be surculose.
Root sprouts can be used to propagate new plants. They also use up a plant’s energy stores and can make a mess of your lawn or landscape. They are also responsible for one of the world’s biggest and oldest life forms.
The world’s largest life form
Tree roots spread. Then they can send up new root sprouts, which then create more roots and more root shoots. Given enough time and space, this process can create something really HUGE! In fact, root shoots are responsible for one of the world’s largest and probably oldest life forms: the singular root system of a grove of male quaking aspen found in Utah. Known as Pando, this root system covers 106 acres, weighs approximately 13 million tons, and is believed to be 80,000 years old. Sadly, Pando, is dying. Pando’s decline is believed to be a combined result of drought, grazing, and fire suppression. The U.S. Forest Service and private groups are trying to save it, but repeatedly killing off the root shoots with grazing (or hand pruners) does take its toll.
Why do trees produce root sprouts?
Some trees are more likely than others to produce root sprouts. In some cases, it is simply the tree’s normal method of propagation. Root sprouts can also be a sign that a tree or shrub is stressed. That stress can take many forms:
What can you do about root sprouts?
First, keep your tree as healthy as possible. Water it, feed it, protect it from lawn competition, weedwackers, and car doors. Mulch around but not touching the tree. Do a little research to find out what type of tree you are dealing with and what its needs are, and provide for those needs. This will reduce the tree’s drive to reproduce in this way.
If you spray herbicides on a root sprout, you will be poisoning the parent plant as well. Instead, you can kill the individual buds by tearing the new growth off, as close to the root as possible. Of course, this may require some soil removal. If you can tear the root sprout off of the root, you are likely to damage or kill that particular bud. If there is a section of root that continually puts out unwanted root sprouts, you can dig up the offending root and severe it from the tree or shrub. If all of that sounds like more work than it is worth, simply snip them off at soil level each time you see them.
There are also products available that you can spray on root sprouts, but I do not use them. Reviews appear to be highly mixed and applying just a little bit too much can seriously damage the tree or shrub those root sprouts came from. Other people swear by them. It's your call.
If you are really sick of all the root sprouts in your lawn, contact a licensed arborist. They can safely apply a growth inhibitor.
Prune limb borers can damage stone fruit trees, such as almond, apricot, cherry, nectarine, and peach, as well as oak. Gumming and reddish orange frass are common signs of prune limb borer infestation.
Prune limb borers (Bondia comonana) are not as common as American plum borers, but it is a good idea to know what to look for, just in case.
Prune limb borer description
Prune limb borer moths are not very large. They have a 3/4” wingspan. The forewings are grey with black and brown markings. Like many grubs, prune limb borer larvae are dull white or pinkish with a large, dark head. They are usually 1” long.
Prune limb borer lifecycle
Prune limb borer larvae overwinter inside your trees in cocoons. In spring, adult moths emerge and mate. Female prune limb borers lay their eggs on callus tissue, where narrow crotches between branches create wrinkled bark, near graft unions, and on crown galls. Eggs are also laid in wounds from pruning, tree supports, or poorly aimed weedwackers. There can be as many as four generations each year.
Prune limb borer damage
It is prune limb borer larvae that do all the damage. As soon as eggs hatch, larvae begin burrowing into the host tree. Erratic tunnels between the bark and cambium layer interrupt the flow of water and nutrients and weaken the tree structurally. Heavy infestations can weaken scaffold branches, making them likely to break off in strong winds and when supporting heavy crop loads.
Prune limb borer management
Mature, healthy trees can often withstand a prune limb borer or two, but young trees can be killed by heavy infestations. Like other borers, these pests are easier to prevent than control. Inside the tree, they are safe from predators and pesticides. Use these tips to prevent prune limb borers from taking up residence in your trees:
Over-the-counter pesticides and insecticides are not effective against prune borers. If you have a badly infested tree, it may be worthwhile to hire a professional to apply a residual, contact insecticide.
We all know what tree branches are, but what are scaffold branches and why are they important?
What are scaffold branches?
Trees have an underground root system, a trunk, primary branches, secondary branches, and so on. Both above and below ground, the fractal splitting of growth creates ever-smaller and more delicate parts. Twigs emerge from lateral branches and lateral branches grow out of primary scaffold branches. Scaffold branches are the heaviest limbs which create the structure of a tree’s canopy, or silhouette.
Scaffold branches and pruning
Pruning and tree training are the best way to ensure your trees are healthy, safe, and productive. Before putting your tree saw to work, you need to know about scaffold branches.
Mature scaffold branches are rarely pruned or removed, unless they are severely damaged or diseased, as they provide the overall structure of a tree’s shape. Young trees, however, must be trained into forms that allow for proper sun exposure and air flow while maintaining branches that are less likely to break once burdened with lateral branches, twigs, leaves, and heavy fruit crops.
The angle at which branches attach to one another, known as the angle of attachment or the branch axil, determines the strength of that connection. Angles of attachment that are too narrow become areas of weakness later on. These V-shaped crotches also provide overwintering sites for American plum borers, prune limb borers, and many other pests. Branch axils of 30° or more generally result in sturdy attachments that can withstand strong winds and heavy fruit or nut crops. Downward hanging branches are highly prone to breakage. The best branch axils are 45° to 60° angles.
Selecting scaffold branches
When training young trees, you want scaffold branches that are appropriate to the species, spaced properly, and at good angles. You should avoid having more than two scaffold branches at the same distance from the ground. Scaffold branches should be at least 8” to 16” apart, vertically. Also, select scaffold branches that are positioned radially around the trunk so that they are not growing directly above or below each other.
As you train your tree, remember to avoid cutting the branch collar and do not use sealants. Sealants often trap moisture against the wound and create the perfect environment for rot. Your tree knows how to heal itself and will form callus tissue over and around the wound.
Take a look at the scaffold branches on your trees. Are they strong and healthy or do you need to do some re-training this dormant season?
Vein clearing is nearly always a sign of viral disease. It can also indicate herbicide poisoning, bacterial disease, or fungal disease.
Normal, healthy leaf veins are green or white, and opaque. In the case of disease or overspray, those veins may become lighter than normal to the point of becoming translucent, clear, or pale yellow. This is a form of chlorosis.
Viral diseases and vein clearing
Viral diseases, such as cucumber vein yellowing, papaya ringspot, and turnip vein clearing, often appear initially as lighter colored veins. Many mosaic viruses, such as cucumber green mottle, pea seed-borne mosaic, and squash mosaic start with similar symptoms.
Other diseases and vein clearing
Fungal diseases, such as Fusarium wilt, occasionally cause vein clearing. Bacterial wilts, such as Verticillium wilt, may also exhibit vein clearing during the initial stages of infection. In bacterial wilts, the xylem walls either dissolve or rupture, releasing fluids into nearby cells and leaving the veins looking translucent.
Vein clearing and overspray
Vein clearing can also be seen when overspray occurs. Overspray describes the way herbicides and other chemicals can drift on a breeze to unintended plants. After landing on a plant, the herbicide is absorbed and transported throughout the plant in the xylem. Older leaves generally exhibit damage to margins (edges) and interveinal (between vein) areas. Younger leaves respond differently, showing chlorosis of the veins, especially the midrib.
Vein clearing can also be a phytotoxic symptom. Phytotoxic means “poisonous to plants”. In some cases, we apply insecticides, oils, or other treatments with the best of intentions. Whether due to extreme sunlight or temperatures or something else entirely, these treatments can go awry, causing symptoms such as vein clearing, along with wilting, leaf loss, or flower drop. In other cases, these symptoms may appear for no obvious reason at all!
Cherry vein clearing, for example, is believed to be a genetic mutation that is spread by grafting affected scions onto unaffected wood. Some researchers believe this mutation is caused by a boron deficiency in the soil, but no one is sure just yet.
In some cases, vein clearing is a short-lived symptom. As the disease or toxicity progresses, vein clearing may resolve itself and show up as completely different symptoms, depending on the initial cause. These symptoms may include dwarfing, puckered leaves, variegated yellow and green on leaves, and vein banding. Vein banding is similar to vein clearing except that bands of translucent and opaque green, yellow, or white are seen.
If you see vein clearing, take a closer look, note any other symptoms and send me pictures!
Clearwing moths are a family of pests that attack many fruits trees, as well as currants and gooseberries. These pests are often mistaken for burly wasps.
There are several different clearwing moth pests and they attack a wide variety of ornamentals and edibles. They include:
Clearwing moth identification and lifecycle
One of the most obvious ways to identify adult clearwing moths is to look at their wings - they are clear. Mostly, anyway. Adults only live for one week, so you don’t get many chances to see them. Front wings tend to be narrow and rear wings are stubbier and wider. Their yellow and black bodies look similar to yellowjackets. This mimicry continues with a behavior commonly seen in wasps, in which both species will periodically run while fluttering their wings. Unlike wasps, clearwing moth adults can also be red, orange, or even dark blue, depending on the species.
As soon as females emerge from their pupal cases, they emit pheromones to attract males. After mating, females lay tiny pale pink to reddish eggs in rough areas of the bark, in wounds, and in cracks and crevices created where branches and twigs fork. One to four weeks later, larvae emerge and the damage begins. Clearwing larvae are 1” to 1-1/2” long, with white to pink bodies and dark heads. They look very similar to American plum borer larvae. Larvae will feed heavily until they are ready to pupate.
Most clearwing moths pupate under bark. The peachtree borer pupates in the soil. Clearwing pupal cases also look a lot like American plum borer pupae, as well as carpenterworm pupae. American plum borers (Euzophera semifuneralis) tend to be found where main scaffold branches join the trunks of ash, olive, and sycamore trees. These pupal cases are thin-walled and brown, and they look very similar to those of bark beetles, longhorned beetles, roundheaded wood borers, flatheaded wood borers, and metallic wood borers. These pupal cases are often found, after they have been vacated, protruding from bark or on the ground under a tree.
Basically, anything burrowing in your trees is bad news.
Damage caused by clearwing moths
Clearwing moth larvae start burrowing into bark, cambium or heartwood of their host tree as soon as they hatch. This burrowing creates galleries that weaken the tree and make it more susceptible to other pests and diseases. It also interrupts the flow of water and nutrients throughout the vascular tissues. Branch die off can also occur. All this burrowing can make bark look gnarled.
Where these galleries occur can help you identify the species. Peachtree borer larvae are most commonly found within a few inches of the soil. Ash borer larvae prefer being 5 to 10 feet up.
In some cases, no controls are needed. Sycamore borers and western poplar clearwings apparently don’t do enough harm to require management. The other species, however, can serious harm your trees.
Since healthy trees are better able to withstand attack, proper feeding and irrigation go a long way toward minimizing clearwing damage. Whitewashing tree trunks and exposed branches reduces sunburn injury. If your soil is compacted, apply a thick layer of mulch or install a ground cover to help aerate the soil. This will help keep your trees healthier, just make sure the mulch or ground cover are kept a few inches away from the trunk to prevent fungal disease. Also, avoid injuring trees with lawn mowers, weed wackers, and other landscape equipment and tools, and remove tree stakes as soon as they are no longer needed.
Pheromone lures can be used to monitor for these pests. Just keep in mind that using pheromone lures attracts pests. These lures interfere with mating, so they can reduce clearwing populations, but this method requires an intensive, ongoing program of pheromone use. It’s probably not worth the effort for backyard trees. You can also buy pheromone traps for peachtree borers and ash borers. If using pheromone traps, be sure to follow the manufacturer’s directions exactly.
Monitoring trees every week for signs of burrowing and pupal cases is an easy way to protect your trees. You may see partially emerged pupae, which can be crushed or skewered with a piece of wire. Gumming around the base of the tree may also indicate peachtree borers.
Beneficial insects, such as braconid wasps, will kill or parasitize clearwing moths and their larvae, so avoid using broad spectrum pesticides and insecticides. Also, you can buy certain nematodes (Steinernema carpocapsae and S. feltiae) to kill peachtree borer, redbelted clearwing, sycamore borer, and western poplar clearwing. Again, follow the directions exactly for the best results.
If a truly valuable tree has a bad clearwing infestation, you should call a licensed pest control applicator. They have access to chemicals that you do not. Most over-the-counter clearwing controls are not effective.
All living things (as far as we know) contain carbon. Your body is 18% carbon. A plant is 50% carbon. The carbon cycle is a series of events that make life possible for us and our garden plants.
What is carbon?
Carbon (C) is an element. For the most part, the amount of carbon in Earth’s sphere of existence is relatively constant. But carbon can take several forms. The graphite in your pencil is an example of carbon. Apply enough heat and pressure and that pencil lead can and will turn into a diamond. In most cases, carbon pairs up with other elements to form new materials, such as amino acids, fats, and carbohydrates. It can also form potassium bicarbonate, a material used to neutralize acidic soil. Very often, carbon pairs with oxygen to form carbon dioxide
Carbon cycle components
Carbon can be found everywhere on, in, and around the Earth. The way carbon moves from place to place, and from form to form, is what makes up the carbon cycle. The components of the carbon cycle are:
Carbon moves through these changes because of biological, chemical, geological, and physical processes.
The carbon cycle in your garden
The same processes occur in your garden, with similar results. Start with your soil. Soil is a living, breathing complex of minerals, organic matter, insects, microorganisms, worms, and more. Microorganisms break down complex molecules into smaller bits, separating carbon from whatever it happens to be bound to and making it and other minerals available to plant roots as food.
You plant a seed and water it. The seed coat softens, a first root, or radicle, emerges and starts absorbing carbon and other minerals. The carbon then becomes part of the plant. The plant matures and produces fruit or other edible parts, which we harvest and eat. The carbon in those parts then becomes part of us. The parts we don’t eat are added to the compost pile, where the carbon attaches itself to other minerals or is released into the atmosphere as carbon dioxide.
The sun shines down on Earth’s oceans, waterways, and soil causing evaporation. That moisture condenses and rain occurs, converting any carbon dioxide in the atmosphere into carbonic acid. This form of carbon falls to Earth, enters the soil, and hydrates any unharvested plants. Excess rainwater leaches into ground water where it ultimately makes its way to oceans. The sun’s heat causes more evaporation, water rises into the atmosphere, more rain, and so on.
How do plants use carbon?
You may have heard that plants take carbon dioxide in and release oxygen during the day, and that that process switches at night. The truth is, carbon dioxide is only taken in, and oxygen is only released back into the environment, while photosynthesis is actively taking place. The act of photosynthesis spilts the carbon dioxide molecule into oxygen and carbon. The carbon is used as a building material, much the way our bodies use carbohydrates. [Carbohydrates are made out of carbon, hydrogen, and oxygen.]
Plants also absorb carbon from the soil, but there has to be the right balance of nitrogen available for plants to use the carbon they need. Nitrogen is the steak and salad equivalent of the human diet. This balance is called the carbon-to-nitrogen, or C:N, ratio. Microorganisms that break down minerals and organic matter into plant-sized bites prefer a C:N ratio of 24:1 to 30:1. If there is too much, or not enough, carbon or nitrogen in the soil, plants will suffer.
Carbon cycling and tap water
Most soils contain a variety of carbon compounds and this can be a problem if your tap/irrigation water is highly alkaline. The chemical reactions that occur between carbonate and bicarbonate ions and alkaline water can make calcium and magnesium less soluble, and harder for plants to absorb. These chemical transformation between these molecules also tends to leave salts behind. Whenever possible, irrigate your garden with rain water.
As we burn fossil fuels and seal the Earth’s surface with concrete, we release an awful lot of carbon into the atmosphere and make it harder for carbon to be absorbed into the soil. Carbon in the atmosphere joins with oxygen to form carbon dioxide. Carbon dioxide (and methane) absorb heat and bounce it back to Earth. This can help prevent another Ice Age and it can lead to global warming, more destructive storms, desertification, rising sea levels, and a harder time for us and our plants.
Removing carbon from the atmosphere is called carbon sequestering. Naturally, carbon is held in plants and soil. When plants are composted or decompose, some of the carbon they contain is returned to the atmosphere and some enters the biosphere, oceans, and geosphere.
As we disturb the Earth’s surface, we break the bonds that hold carbon in place. Instead of plowing or rototilling, you can reduce the amount of carbon released into the atmosphere by practicing no-dig gardening. [It’s easier on your back, too.]
Carbon is sequestered into the soil by plant roots. Plant roots secrete carbon in something called exudates. Root exudates feed beneficial bacteria and fungi in the soil which then help feed your plants. These root exudates also promote soil health and reduce erosion.
There are many ways that you can reduce the amount of carbon in the atmosphere:
Finally, growing your own food is one of the easiest ways to reduce the amount of carbon released into the atmosphere. Not only does it reduce the demand for highly tilled fields around the globe, it reduces the number of trucks, ships, farming machinery, and storage facilities needed to fill your larder. Just go outside and pick what you need!
Whether you call them chickpeas, Bengal grams, Egyptian peas, or garbanzo beans, you definitely do not want them infected with this fungal disease. Ascochyta [ask-uh-SHOO-tuh] blight, also known as blackspot, is a major disease of garbanzo beans.
Not to be confused with the other black spot (Diplocarpon rosae), which primarily affects leaves, Ascochyta blight can infect any aboveground portion of your chickpea plants, as well as your lawn. Lawns infected with Ascochyta blight suddenly develop brown patches of dead-looking grass. Ascochyta blight is caused by Ascochyta rabiei (formerly known as Phoma rabiei).
Ascochyta blight symptoms
Brown lesions that start at the base of seedlings may start out looking like damping-off disease, but these lesions continue to move up the plant, eventually affecting everything aboveground.
Infection may also first appear on leaves and work its way elsewhere on the plant. Foliar infections start out as light brown spots. Once the fungi start reproducing, you will be able to see tiny black, raised dots within these brown spots. These black dots will appear in circles of their own.
Stem lesions can cause the plant to fall over. Pod lesions reduce seed production and can cause seed shrinkage and discoloration.
Ascochyta blight lifecycle
In California, garbanzo beans are generally planted in November. This sets them up for Ascochyta blight because the spores grow best in cool, damp weather. Temperatures between 68°F and 77°F are ideal for this disease to develop. There are different forms of this fungi. One form is airborne, while the other is spread by rain and irrigation water. When these two forms meet under optimal conditions, the disease begins.
Ascochyta blight management
Ascochyta blight can be spread by infected seeds, so always start your garbanzo bean crop with certified disease-free seeds. Do not use that bag of garbanzo beans from the grocery store. The price might be appealing and those seeds are safe to eat, but they may also carry any number of pests and diseases that might take years to get rid of. You can also select disease resistant varieties. According to UCANR, the following varieties of garbanzo are currently resistant to Ascochyta blight: Sierra, Dylan, Sutter, San Joaquin, and the Airway Farms (AWF) series. That resistance can and will change because fungi evolve faster than plants.
At the first sign of infection, the affected plant should be removed and tossed in the trash. You don’t want to leave infected plant material in the garden or compost pile because this can simply spread the disease to more plants.
Ascochyta blight does not survive in the soil, so crop rotation is a good way to break the disease cycle.
If Ascochyta blight has been a serious problem in past years, space plants out more for better air flow, and plant seeds as late in the season as possible.
Fungicides can be used at the first sign of disease and reapplied according to package directions.
The warm heat of curry dishes can all be grown in your garden. Curry plants, however, are often mislabeled and misunderstood. Before we really dig in, what does the word curry actually mean?
We think we know what curry means. The dictionary tells us that curry is “a dish of meat, vegetables, etc., cooked in an Indian-style sauce of strong spices and turmeric and typically served with rice.” But curry is more of a colonial grab bag name for a wide variety of regional dishes that can be prepared with a complex assortment of herbs, spices, and other flavorings, depending on the region of origin. These ingredients may or may not include:
And curry leaves. There are two distinctly different plants sold as “curry plants”. One is the real deal. The other is not.
Fake curry plants
Helichrysum italicum, sometimes listed as H. angustifolium, is a pale green European herb with yellow flowers that grows well in dry, rocky soil. This plant smells a lot like curry, hence the name, but it does not taste like curry. Also known as Italian strawflower and immortelle, young shoots are sometimes used in Mediterranean dishes for their bitter, sage-like flavor, and never in curry.
True curry plants
True curry plants are trees. The curry leaf tree (Murraya koenigii) is a member of the rue family, along with citrus. Being tropical to subtropical, curry leaf trees grow best in Hardiness Zones 9 - 12. They are very sensitive to frost damage. They can grow from 6 to 15 feet tall and 4 to 12 feet wide. There are three types of curry leaf tree: regular, dwarf, and gamthi. Dwarf trees are shorter and wider than regular trees and the leaves are narrower. Gamthi varieties grow very slowly and they produce thicker leaves with the strongest aroma.
Curry leaf trees will produce berries that will open up into fragrant white flowers. You can increase leaf production by removing those berries before they open.
How to grow curry leaf
Curry leaf plants can be started from seeds, suckers, or stem cuttings. Only fresh, ripe berries contain viable seeds and the husk must be removed before planting. The seeds contained in dried berries will not germinate.
Containerized curry trees
Curry leaf trees can be grown in containers, as long as they have nutrient-rich potting soil and good drainage. They need to be moved to slightly larger containers every few years. By the time your curry tree is 10 years old and at its mature size, it should be in a 30-gallon container.
Caring for curry trees
These trees prefer full sunlight but can grow in partial shade. Scorching summer sunlight can sunburn the leaves. If grown indoors, grow lights may be needed. If grown outdoors, your curry leaf tree will need to be brought indoors in winter if you live in Hardiness Zones 1-8. It will also need protection from wind. In either case, be sure to allow the soil to dry out completely between waterings to avoid root rot.
Curry trees should be fertilized once a month, March through October. Also, curry trees use a lot of iron, so iron sulfate should be added every other month, or so.
Curry tree pests and diseases
Mites and scale insects are the two most common pests of curry trees, along with aphids and citrus mealybugs. Asian citrus psyllids may also be present and this poses a serious problem. Asian citrus psyllids can carry a fatal disease called huanglongbing. Infected trees must be destroyed. Before accepting curry tree seeds or cuttings, make sure they are not from a quarantine zone. Leaf spot is another disease that may occur in curry leaf trees.
If you love curry, starting your own curry leaf tree is one way to enjoy the very freshest ingredients.
Stink bugs have shield-shaped bodies and most of them are plant pests. The rough stink bug, however, occasionally eats pests!
As true bugs, rough stink bugs (Brochymena sulcata) are cousin to aphids, leafhoppers, and scale insects. There are several different subspecies of rough stinkbug and none of them are 100% beneficial.
Rough stink bug identification
Their classic stink bug shield-shaped body is rather flattened and a bumpy mottled grey and black. This coloration makes them blend in well with bark. They average 1/2” to slightly more than 3/4” in length.
Do not confuse rough stink bugs with brown marmorated stink bugs (Halyomorpha halys.) or consperse stink bugs (Euschistus conspersus). Brown marmorated stink bugs are relatively new to California and pose a serious threat to gardens and orchards. They have white bands on their antennae and legs, the front of the head is more blunt than other species, and the thorax is smooth. Consperse stink bugs have no banding on the antennae, but dark spots on the legs, the thorax is smooth but somewhat convex, and this species is smaller than others.
Rough stink bug diet
Like other stink bugs, a rough’s favorite foods are plant-based. While other species prefer fruits and vegetables, the rough stink bug diet is predominantly the leaves and developing seeds of ash, boxelder, walnut, willow, and many other trees. The thing that makes the rough stink bug beneficial is that they also feed on caterpillars and leaf beetle larvae.
Rough stink bug lifecycle
Rough stink bugs spend their winters hidden under logs or the bark of trees. They may also try to get in your home. If they do, keep in mind that their name is an important clue. If you vacuum them up or squash them in your home, there will be consequences. Stinky ones. Instead, sweep them up with a dustpan and drop them into a container of soapy water or feed them to your chickens.
As spring temperatures rise, rough stink bugs become active again and start looking for a mate. Mated females lay clusters of 10 to 20 white, elongated eggs before they die. Two weeks later, the eggs hatch and pale colored nymphs emerge and begin feeding. There is one generation per year in most regions.
In most cases, getting rid of stink bugs is a good idea. The rough stink bug is an exception.
You can grow a surprising amount of food in your own yard. Ask me how!