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.
Extermigate is a word I just made up.
I was looking for one of those lovely, lengthy German words that describes something so well, but I couldn’t find what I was looking for. I was hoping for a word to describe the act of interrupting an insect’s lifecycle by wiping the eggs off before they hatch. No such word. So, I took extergimus, the Latin word for “wipe off”, and gave it a little twist. From now on, if anyone asks, extermigate refers to the act of wiping insect eggs off of a host plant. Ta da!
In many cases, it is the larval form of an insect that causes the most damage. Voracious eaters, they can sever seedlings, turn leaves into lace, and hollow out cabbages before they have a chance to form. Imported cabbageworm butterflies are a perfect example.
Tiny pale eggs are laid by the dozens on the underside of young leaves. In no time at all, these eggs hatch into tiny larvae that don’t stay little for long. All day, they chew holes in leaves, growing larger by the minute. Since they tend to turn the color of the leaves they are feeding on, they are difficult to see until the damage becomes extensive. Instead of losing crops to pests like these, you can extermigate the eggs and be done with it.
How to extermigate
Much like tree rubbing, in which you use a gloved hand to rub off unwanted new shoots before they get large enough to require pruners, exterminating insect eggs is a lot faster and easier than hunting down fat green larvae, removing shredded leaves, and hosing all that frass (bug poop) out of your decimated plants
Every few days, simply take a walking tour of your susceptible plants. In the case of the imported cabbageworm butterfly, that would mean all of your cruciferous vegetables: broccolis, Brussels sprouts, cabbages, cauliflowers, chard, and kale. Inspect the underside of leaves for signs of eggs. If you see any, simply wipe them off. They will fall to the ground where, when they hatch, they will have no food and die.
Milk in the garden? Some say it can be used as a fungicide or fertilizer, while others praise milk’s ability to acidify the soil. Who is right? Are these myths or useful tools? Let’s find out!
According to Mother Earth News, a Nebraska farmer, David Wetzel, worked with a local County Extension agent, a soil specialist, a weed researcher, and an entomologist for 10 years to study the effects of milk on plant and soil health. According to his experience, plant production increased, soil porosity doubled, microorganism populations increased, grasshoppers abandoned his pastures, his pasture grass contained more nutrients and sugars (brix levels), and even his cows were healthier and produced more milk. At first glance, all that falls under the Too Good To Be True category, but is it? Can spraying milk on your garden plants really make things that much better?
Before we learn what milk can and cannot do in the garden, you need to know that Wetzel’s ‘research’ was never published, and that the real data showed absolutely no correlation between milk and any of the benefits listed. You can read an excellent summary of this at Garden Myths. After winnowing through several real studies, I learned that milk can be useful in the garden in some cases, but not all.
Milk as fertilizer
Anything added to the compost pile or the soil will ultimately be broken down by microorganisms into its elemental parts. While milk is the perfect food for baby mammals, it may or may not be good for plants. Milk contain amino acids, enzymes, fats, minerals, proteins, salts, sugars, and vitamins. Those minerals include calcium, chloride, citrate (an ester of citric acid), magnesium, phosphate, potassium, and sodium. Most of those minerals are useful to plant health.
The protein in milk contains an average of 0.5% nitrogen, another useful plant nutrient, but in a very small supply. So, yes, milk can be used as a fertilizer, but not a very good one. By the time you added enough milk to get a reasonable response, your garden would smell like a rotten dairy.
Milk as soil amendment
Milk can add calcium to the soil, improve porosity, and acidify the soil. That’s what they say, anyway. The fact is, milk is 90% water, which does nothing to improve soil structure or porosity. It also contains very little in the way of organic matter.
Milk starts out with a pH of 6.4 to 6.8, which is great for plants. When milk starts to curdle, it has a pH closer to 5.0, which is acidic. Putting practically anything with a pH of 5.0 in your soil will alter its pH temporarily. As expensive as milk is, there are far more affordable, effective methods, but it won’t hurt.
Milk as insecticide
It is said that if you spray soft-bodied insects, such as aphids, with milk, they will weaken and die because they do not have a pancreas with which to digest the milk sugars. Huh. That just doesn’t sound right to me. I mean, soft-bodied sap-sucking insects live on sap. Sap contains a lot of sugar. Insects may not have a pancreas but they sure know how to process sugar!
Some researchers believe that aphids may be deterred by foliar sprays of milk. It is not yet known why or how the milk spray does this. It may be that aphids simply do not like the milk film left on the plants, or it may be that microscopic pathogens that grow on the milk are a threat to aphids. We don’t know.
Milk as disease treatment
Foliar sprays of milk on wheat and grape, squash, melon, and pumpkin leaves is said to prevent fungal and bacterial diseases, such as powdery mildew and leaf black spot. There is, however, no research that demonstrates milk can control black spot on roses or other ornamental plants. Most of the studies that support this claim were performed in greenhouses, rather than outdoors, which makes a big difference. Just because something works in a greenhouse, a highly controlled environment, does not mean it will work in the field.
Generally speaking, milk or whey, applied before exposure to powdery mildew does reduce disease incidence. This may be because the benign microorganisms that start growing on the milk make it more difficult for powdery mildew organisms to take hold. Another theory is that the fatty acids contained in milk have antifungal properties. It may be for another reason altogether. We don’t know yet. Note that none of these studies succeeded using nonfat milk.
Research has also shown that foliar sprays of milk are effective in treating viral diseases, particularly tobacco mosaic and other mosaic diseases on barley, beans, beets, celery, peas, spinach, sunflowers, tomatoes, and zucchini. It is believed that the milk may either deactivate the viruses, or physically isolate them, but no one knows for sure. The milk spray may also prevent aphid attack, thereby reducing the number of aphid-borne viral diseases.
Problems with milk in the garden
The main problem associated with milk in the garden is that there has been very little scientific research conducted. Most of the information available is anecdotal, at best. Besides being expensive, there are three problems you should keep in mind before deciding to use milk in the garden:
How to apply milk
If you decide to use milk to prevent disease, it is recommended that whole milk be sprayed on soil prior to planting and again when insects appear or just prior to when powdery mildew and similar diseases are expected to occur. You can also dump sour milk into your compost pile or around acid-loving plants, such as blueberries.
So, can milk help improve your plant and soil health? Yes, and no. Used as a preventative antifungal, antiviral, antibacterial treatment, milk may reduce disease incidence by 50% to 70% on some plant species.
Commonly referred to as ladybugs in the U.S. and ladybirds in Britain, a more correct name is lady beetle, even though some of them are male. In most cases, lady beetles are beneficial insects, eating a surprising number of soft-bodied, sap-sucking insect pests. The Asian lady beetle is something of an exception.
First introduced to the United States from Japan in 1916 to control aphids, Asian lady beetles (Harmonia axyridis) did not start to thrive in North America until 1988. First seen succeeding in the wild in Louisiana, Asian lady beetles were well established in the Northwest by 1991, the Northeast by 1994, and in the Midwest by 2000. Asian lady beetles are now found throughout the U.S. and Canada, and in parts of Europe and Africa. And for some, that’s a problem. We will get to that in a moment.
Asian lady beetle description
Slightly larger than other lady beetle species, Asian lady beetles have the same half-dome shape of other ladybugs. Legs tend to be brown while the antennae, head, and mouthparts are pale yellow, though they can be tinged with black.
This species appears in a very wide variety of colorations. They can range in color from red to yellow, or even black. The black variations may have 2 or 4 red spots, though not always. The red to yellow varieties may have up to 22 spots or no spots at all. The thorax, or middle part, (where the legs and wings attach) tends to be white, cream, or pale yellow, with variable black markings that can range from a few dark spots in an “M” or “W” formation to almost completely black. The pattern may also be in the shape of a trapezoid. Many other coloration patterns have also been recorded.
If you turn an Asian lady beetle upside-down, you would see that it is dark, with a reddish brown border. This, and the fact of its larger size, are the two most reliable methods of identification.
Because of the variety of colorations, Asian lady beetles also have a variety of names, including harlequin lady beetle, Japanese lady beetle, multicolored Asian lady beetle, multivariate lady beetle, pumpkin lady beetle, and southern ladybird.
Asian lady beetle larvae, like other lady beetle species, look like miniature alligators, with spines and tubercles. These black to blue-gray larvae go through 4 developmental stages, or instars. The final stage can be quite colorful with bright orangish-yellow patches on the sides of the abdomen.
Asian lady beetle lifecycle
Also known as Halloween lady beetles, these insects often invade homes during October in search of a place to overwinter. Using visual cues and pheromones to signal each other, they will often congregate in huge numbers. As temperatures drop below 50°F, they slow and then stop moving. Before that time, unmated females will seek out dry, dark crevices, such as inside walls and furniture. They also gather in the upper corners of windows, where they collect the sun’s heat. They seem to prefer light-colored buildings and dark screening material. Subsequent generations will follow chemical trails to favored overwintering sites.
In spring and summer, mating occurs and bright yellow eggs are laid in clusters on the underside of leaves. Within 3 to 5 days, these eggs hatch, releasing the classic alligator-shaped ladybug larvae. The larval stage lasts 12 to 14 days, followed by a 5 to 6 day pupal stage. Adults can live 2 to 3 years and there can be multiple generations in a single year. A single female may lay 1,600 to 3,800 eggs in her lifetime.
Asian lady beetles are also known to swarm in summer, creating a nuisance for picnic-goers.
Asian lady beetles have good eyesight. When threatened, Asian lady beetles release a foul odor, staining bodily fluids (“reflexive bleeding” from their knees), and they bite. Yes. That’s right. Asian lady beetles will bite you. And some people are allergic.
Asian lady beetle diet and host plants
Asian lady beetles are commonly found on apple trees, alfalfa, Christmas trees, grains, maple trees, pecan trees, rose bushes, walnut trees, and wheat. A single adult Asian lady beetle can eat 90 to 270 aphids each day, and one larva can devour 600 to 1,200 aphids as it develops. Adelgids, asparagus beetle larvae, mealybugs, moth larvae, psyllids, scale insects, spider mites, thrips, and whiteflies are also popular food stuffs. So are other lady beetle species - and other Asian lady beetles. These predators are voracious!
The problem with Asian lady beetles
Being slightly larger than other lady beetle species. Asian lady beetles have been devastating to native populations. Suddenly, beneficial ladybugs went from predator to prey. In addition to eating indigenous ladybugs, Asian lady beetles outcompete our more gentle ladybugs, leaving them without adequate food supplies. Also, Asian lady beetles are highly resistant to common lady beetle diseases. If that weren’t bad enough, Asian species carry a parasite to which they are immune, but other lady bugs are not. This parasite infects and then kills local lady beetles.
As Asian lady beetles devour, outcompete, and infect local ladybug populations, biodiversity is reduced and a domino effect occurs in ways which we have only partially identified. Asian lady beetles are now considered one of the world’s most invasive species.
Asian lady beetles are causing problems for grape farmers, too. As grapes are harvested, Asian lady beetles are often caught up in the harvest, ultimately altering the taste of the wine produced by those grapes.
Experts predict that things will settle down, once Asian lady beetle predators appear on the scene, but that can cause yet another set of domino-effects to become active. The delicate balances that evolve slowly over time have a difficult time dealing with the sudden changes we humans tend to create.
Asian lady beetle management
It is probably too late to do anything about this invasive insect. You are urged to not use pesticides. If Asian lady beetles appear in your home, you can gently sweep them up and toss them outside. Some people vacuum them up only to discover that alarming these insects results the stink and stain mentioned earlier. After kicking out the interlopers, inspect your home for points of entry around doors, windows, and pipes, and fill those spaces with expandable insulation or caulk.
Love ‘em or hate ‘em, Asian lady beetles are here to stay.
Winter is when many fruit and nut trees and cane fruits enter dormancy. This is an excellent time to prune and train trees and canes. It is also a good time to apply anti-pest and anti-disease treatments. But some of those treatments should be applied when a plant is in full dormancy while others should be applied during the delayed dormant period. Let’s find out more about these two time frames and how to make the most of them.
Life in the year of a tree
Summer is a riot of leaf, flower, and fruit development. Ample warmth and moisture combine to allow trees and canes to invest all their resources into procreation. As days begin to shorten and temperatures start to drop, deciduous trees, grape vines, and bramble fruits pull resources from leaves, as seen by the changing colors and ultimate leaf drop. During the coldest part of winter [December and January if you live in San Jose, California], most fruit and nut trees are in full dormancy. Sometime around February, things start moving again. Sap starts flowing. Buds start swelling. This is called the delayed-dormant period and it continues until spring, when the tips of the buds start to turn green.
Timing tree treatments
Horticultural oils, fixed copper, Bordeaux mixture and fungicides can be used to suffocate pest eggs, thwart fungal diseases, and break many other disease triangles. But the timing of those treatments is critical for them to work properly. Spray too soon and rain will wash it away before it ever comes into contact with a pest or pathogen. Too late is, well, too late. Also, coverage must be complete to the point of it dripping from every surface.
Generally speaking, these treatments need to be done before buds start to swell. Applying horticultural oils during summer, for example, when trees are more likely to be water-stressed, can lead to severe leaf loss and sunburn damage, reducing crop size and making trees susceptible a number of other pests and diseases. Applying treatments during freezing weather can be just as bad. Ideally, tree treatments should be applied on cool (50°F - 70°F), slightly overcast days, when rain, fog, and wind are not expected for at least 24 hours.
Different species have different ideal “windows” of treatment opportunities:
Timing also depends on the specific pest or disease. Full dormancy is the best time to treat for San Jose scale and peach leaf curl. Either full dormancy or the delayed dormant period can be used to treat for aphid eggs, European fruit lecanium nymphs, fruittree leafrollers, peach silver mites, and peach twig borer larvae. You can also wait until blossoms appear to use Bt to treat for peach twig borers.
The delayed dormant period is the best time to apply treatments for these specific problems:
In some cases, your tree, vine, or canes will need more than one type of treatment. Dormant oil may be needed to combat certain pests, followed by a sulfur treatment to prevent fungal disease. It is very important that at least 30 days separate those two treatments. Also, sulfur should not be applied on days when temperatures will go above 75°F.
Keep in mind that treatments should not be given as a matter of habit. They should only be used when they are needed, as evidenced by infestations of infectious the previous year. Use a hand lens or magnifying glass to inspect buds for signs of aphid or other insect eggs. If your trees do not need treating, don’t do it. This is especially true for fixed copper treatments, as copper can build up in the soil to reach levels that are toxic to valuable microorganisms.
Whichever treatments you decide to use, ALWAYS apply them exactly as package instructions state and wear protective clothing and goggles. Using these products incorrectly can harm you, your trees, and groundwater supplies.
Other actions you can take to ensure the health of your fruit and nut trees during delayed dormancy include:
February may seem like a quiet time for gardeners, but it is the perfect time to get outside and take a closer look at stems, twigs, bark, buds and spurs. Identifying potential pest and disease problems ahead of time, and treating your trees at the ideal time to combat those problems can make the rest of your year that much easier and your trees more productive.
Insect pests can damage garden plants by feeding on them, burrowing into them, or by carrying diseases.
Ants, aphids, scale insects, mites, thrips, psyllids… the list never seems to end! Practically any time of year, one sort of insect or another is trying to take a bite out of your garden plants. If that weren’t bad enough, many of these pests spread diseases as they feed and travel around. There isn’t a gardener alive who hasn’t wished for an easy solution to the constant onslaught. But easy solutions often backfire and insecticides are a perfect example.
How insecticides work
Insecticides are formulated to repel, kill, or otherwise harm insects. These agents are classified as either systemic or contact insecticides. Systemic insecticides are absorbed by the plant, making it toxic to anything that eats it. Systemic insecticides have residual, long term actions, while contact insecticides have no residual actions. Contact insecticides simply have to come into contact with an insect to be toxic.
The mode of action by which an insecticide works is important as it determines which other living things may be affected. Some insecticides work by damaging an insect’s nervous system, interrupting feeding and reproductive behaviors, while other insecticides attack the exoskeleton. A damaged exoskeleton allows insects to dry out, causing death by desiccation. Growth regulators (e.g., pyriproxyfen, methoprene) stop insects from molting or laying eggs. Ovicides kills eggs. Larvicides kill larvae.
Insecticides also come in several forms: sprays, dusts, baits, and gels. Depending on which form you use and how you use it, the poisons intended for pests can harm pets, people, and the environment.
Insecticides can be repellent or non-repellent. Repellents discourage insects from bothering a plant in the first place. Non-repellents are especially effective against social insects, such as ants. Being a non-repellent, the insecticide is not offensive to the pest, so they walk through it and end up carrying it back to their nest, ultimately killing the entire colony.
Types of insecticides
There are three basic types of insecticide: natural, inorganic, and organic. Natural insecticides are enzymes and other protective substances made by plants as part of their arsenal against insect pests. These natural insecticides include nicotine, neem, and pyrethrum. Pyrethrum is made from the dried flower heads of two chrysanthemum species: Chrysanthemum cinerariifolium and Chrysanthemum coccineum. Other natural insecticides include the chemical that gives horseradish its fiery bite, rosin, and wintergreen.
Inorganic insecticides are made from metals. Organic insecticides are organic chemical compounds that are generally work by making contact with an insect.
The problem with insecticides
Being poisons, insecticides can affect our health, as well as kill insects. Insecticides can also remain in the food supply, increasing in concentration as they move up the food chain. This is important because we are at the top of our food chain. [It is a lot like mercury in fish.] Many of these problems can be reduced or eliminated by understanding the different types of insecticides and using them responsibly.
Like weedkiller sprays, broad-spectrum insecticides are very appealing. A problem appears. You spray it. The problem is gone. Fantastic. Except that the problem is not gone. In fact, the problem just got worse. By spraying broad-spectrum insecticides, all insects are affected. Beneficial predatory insects, pollinators, burrowing soil arthropods, and our beloved honey bees are all subject to the same poisoning.
There are several type of broad-spectrum insecticides, in order of toxicity, all of which interfere with nerve cell transmissions:
Educate yourself about ingredients
Before applying insecticides, you can protect yourself and the environment by learning more about the ingredients. For example, some beneficial insects, such as lacewings, are tolerant of pyrethroids, while beetles, parasitic wasps, and predatory mites are very sensitive to the same chemicals.
You should also ask yourself how long the ingredients of any particular insecticide will remain in the environment. Insecticides are commonly grouped by persistence: short (days), intermediate (up to 6 weeks), or long (months).
Finally, are insects developing a resistance to an insecticide? If so, it should be avoided and another product used.
Reducing risks associated with insecticides
Before resorting to the use of insecticides, be sure you have done the following:
In many cases, it is against federal law to use insecticides improperly, and for good reason.
As quickly as insects can reproduce, it often feels like a losing battle. This is what makes the use of modern insecticides so appealing. Insecticides are an easy way to kill insects. But not all insecticides are safe to use on edible plants. And many insecticides interfere with the delicate balance that exists in a healthy environment. Knowing more about the different ways insecticides work, and how and when to apply them properly, can prevent longterm problems while still reducing the damage done to your plants by insect pests.
Leaf rot causes crisp, leafy greens turn brown and mushy
Your spinach, endive, escarole, lettuces, mustards, and Swiss chard are all susceptible. So are your lentils, strawberries, beans, peas, okra, and many cucurbits.
What is leaf rot?
You’ve seen it in your refrigerator. You place a fresh head of lettuce in the crisper drawer. The next time you look, leaves have turned brown and mushy. What happened? What happened is fungi or bacteria found a hospitable location and started reproducing and feeding. Rotting is the breakdown of complex structures by those tiny life forms.
Causes of leaf rot
Leaf rot can be a case in which leaves were exposed to too much moisture and decomposition set in. Leaf rot can also be a symptom of any number of fungal or bacterial diseases, most often caused by Fusarium, Pythium, Phytophthora, and Rhizoctonia. These leaf rot diseases include cherry mottle, cucurbit wet rot, carrot leaf rot, lentil leaf rot, pigeonpea leaf rot, and white mold.
Like most rots, moisture is a critical component. Allowing water to sit on your leafy greens invites trouble, as does saturated soil.
Preventing leaf rot
Rather than losing your leafy greens and other garden favorites to leaf rot, there are steps you can take to prevent this problem. First, healthy plants are better able to protect themselves, so select plants best suited to your microclimate and avoid overwatering. Good drainage will also help prevent conditions that lead to leaf rot. Instead of overhead watering, use drip irrigation, a soaker hose, or furrow irrigation.
If leaf rot does occur, dig up infected plants and throw them in the trash. This will reduce the chance of neighboring plants suffering a similar fate.
Eating lead-based paint is a bad idea. You don’t want it in your garden soil, either. But how do you know if it is there and what can you do about it if it is?
Lead is a soft, heavy metal that has been used to make paint, pipes, bullets, batteries, pewter, leaded glass, and in gasoline. Lead is still used to make high voltage power cables, lead-acid batteries, solder, and wicks for cheap tea lights.
Damage caused by lead
Lead is a neurotoxin that accumulates in bones and soft tissues, causing brain, kidney, liver, reproductive system, digestive system, and nervous system damage. It also reduces intellect and is believed by some to be associated with increased rates of crime and violence. Many historians attribute the Fall of Rome to the fact that their pipes many of their food containers were lined with lead.
Most countries have banned the use of lead in products that might cause exposure, but not all. Countries such as China, India, and Indonesia still use lead in many products which is why it is important to verify that planting containers, coffee cups, and other food-related items are safe to use. Red and yellow ceramics are the most likely to contain lead.
Where does lead come from?
Lead was added to gasoline as an anti-knock agent in 1921. By the 1970’s, over 75% of the U.S. population had elevated lead levels in their blood. That number dropped to just over 2% twenty years later, after lead was removed from gasoline. All those fumes, spewing forth for over 50 years, contained lead. That lead settled on roads, yards, gardens, and fields. Rain and irrigation water leached some of that lead into rivers, lakes, and oceans.
Lead can also find its way into your garden soil by sanding, chipping, or sandblasting lead-based paint from older buildings, or when old lead pipes, roof flashing, or lead-batteries are allowed to sit on the ground and break down.
How much lead is in your soil?
Lead occurs naturally in the soil. While there is no safe level of exposure, natural concentrations range from 10 to 30 parts per million (ppm). Areas where leaded gasoline was still in use in 2014 were found to have lead levels of 100 to 1,000ppm. Homes painted with lead-based paint that were located near high traffic roads could have had lead levels as high as 3,000ppm.
Until you get your soil tested, there is no way of knowing how much lead is there. I use the UMass Extension Soil Testing Lab. My soil test lists anything below 22ppm as acceptable. My results were 2.1ppm in 2015 and 2.0 in 2019. Lab-based soil tests are inexpensive and they provide valuable information both for your plants’ health and your family’s health.
How to manage lead contaminated soil
If your soil is contaminated, your biggest health risk is breathing in dust that contains lead. One of the easiest ways to reduce the risk of inhaling lead dust is to grow cover crops or mulch over the area. You can also cover the contaminated area with 4” to 6” of clean soil, to reduce the risk of dust.
You can also use certain amendments that bind to the lead, making it less likely to be absorbed by plants or released into the air via dust. Lead will bind to organic matter, such as aged compost, but this treatment needs to be repeated as the compost breaks down. Depending on your soil’s phosphorus levels, the addition of more phosphorus may improve the binding action. Too much phosphorus is bad for plants, so check your soil test results before using this method.
As soil pH increases, becoming more alkaline, plants absorb more lead. Maintaining a soil pH of 6.5 to 7.5 is ideal, both for plant health and to reduce lead absorption.
Can I grow edible plants in lead contaminated soil?
Plants can grow in soil with lead levels as high as 500ppm. Lead moves very slowly through plants, staying mostly in the roots. According to the University of California Department of Agriculture and Natural Resources, “Fruits such as tomatoes, peppers, melons, okra, apples, and oranges and seeds such as corn, peas, and beans generally have the lowest lead concentrations and are the safest portions of the respective plants to eat [when] grown in lead-contaminated soils.”
Crops that should never be grown in lead contaminated soils include leafy greens, such as chard and collards, and root vegetables, such as beets, carrots, potatoes, and turnips. These crops are better grown in raised beds with clean potting soil.
Also, if you know your soil contains high levels of lead, be sure to wash all produce thoroughly to remove any lead dust that may be present.
Finally, pencil leads have never been made from lead. They are made with graphite.
Now you know.
When I first read the name drugstore beetle, I conjured up images of an 1800s mercantile being harassed by a gunslinging beetle wearing spurs. I have no idea why.
The truth is, drugstore beetles (Stegobium paniceum), also known as biscuit beetles or bread beetles, are very tiny and don’t look like much of a threat to anyone. Looks can be deceiving.
Drugstore beetles got their name because, until relatively recently, most drugstore pharmaceuticals were made out of dried plants. Drugstore beetles have also been known to feed on chemicals, such as strychnine, once commonly found in drugstores.
Drugstore beetle description
Being brown and covered with microscopic hairs, drugstore beetles look similar to cigarette beetles, but are somewhat larger at 1/8” (3.5mm) in length. Also, where cigarette beetles have smooth bodies and serrated antennae, drugstore beetles have longitudinal grooves along the elytra (wing cases) and antennae that end with three tiny segmented clubs. Drugstore beetle larvae are white grubs with very fine hairs.
Drugstore beetle lifecycle
Female drugstore beetles can lay up to 75 eggs at a time, and the egg-laying season can last for months. That works out to a tremendous number of offspring. Those eggs are usually laid in dried foods, such as cereals, dried fruit, grains, herbs, and nuts. Eggs may also be found in dried meat, hair, wool, and candy.
As those eggs are laid, they are covered with a yeast fungus. This fungi and the beetles cannot live without each other. This is an example of obligatory symbiosis. In less than two months, larvae pupate into adulthood, protected by tiny cocoons, and the cycle begins again.
Damage caused by drugstore beetles
After the eggs hatch, it is the larvae that cause damage by burrowing through and feeding on a wide variety of materials. They also leave frass (big poop) and webbing behind, as well as stray hairs and secretions.
Drugstore beetle larvae love dried plant products, such as cereals, beans, pasta, rice, bread, flour, and spices. Apparently, paprika and chili powder are drugstore beetle favorites, though they will eat practically anything. Larvae are also commonly found in tea, potpourri, tobacco, wreaths, and birds’ nests and they have been known to damage books, leather, hair, and museum specimens.
In the garden, drugstore beetles are a major pest of cumin.
Drugstore beetle control
Drugstore beetles are often carried into the home, garden, or landscape in bulk items, such as grass seed, bird seed, or dry pet food. They may also hitch a ride on packaged food. This is why it is important to look for holes in food packaging and avoid those products. While adult drugstore beetles do not eat, they often chew holes in plastic, foil, and paperboard food packaging. You may also see pockmarks in crackers and pasta. Inspecting foodstuffs and bulk items before you bring them home can prevent infestation.
When bringing crops, such as beans and other seeds, into the home., it is a good idea to freeze them overnight to kill any larvae that may be lurking. This is an easy way to keep your home from becoming infested. Diatomaceous earth (DE) can also be used lightly in areas where drugstore beetles may be lurking.
Pheromone traps and insecticides are not effective against drugstore beetles.
Chlorine in your plants? Yes. Well, sort of.
Before you go grab a jug of bleach, you need to know that laundry bleach most commonly refers to a dilute solution of sodium hypochlorite. This is NOT something you want anywhere near your plants. In fact, high concentrations of chlorine are fatal to all living things. It was even used in World War I as the first chemical warfare agent.
We are not quite ready to throw the book at chlorine, however. We need to know that chlorine is an element, much like copper or nitrogen, used by plants as food. You don’t hear much about it because plants only need it in tiny amounts. Once called trace elements, minerals used in such small amounts are now referred to as micronutrients. The form of chlorine used by plants is called chloride (Cl-).
Forms of chlorine
Chlorine is a highly reactive element. As such, it rarely occurs naturally by itself. Instead, it binds to other, nearby elements. In fact, chlorine will pair with practically every other element in the Periodic Table. Those parings occur because chlorine most commonly exists as an anion, or negatively charged, somewhat unstable atom, called chloride. To stabilize its outer electron field, chloride shares electrons with other elements, creating molecules. Some of these more familiar ‘binary chlorides’ include:
We all know ‘salting your fields’ ends badly for plants. Unfortunately, it can be difficult to know just how much chlorine is in your soil. Most soil tests do not include chlorine results. If your soil test indicates excessive levels of other anions, such as sulfur and boron, it may be difficult for your plants to absorb the chlorine they need. Only a lab-based soil test can tell you what those levels are and how they are changing over time. If you see signs of chlorine toxicity, you may want to limit the use of calcium chloride and potassium chloride.
How plants use chlorine
Chlorine aids plant metabolism during photosynthesis. It is necessary for osmosis and fluid balance within plants, working in tandem with potassium ions to open and close the stoma. As an anion, chlorine binds with many cations, or positively changed ions, helping to transport them throughout a plant. Chlorine also appears to have antifungal properties which are currently being explored.
Chlorine toxicities and deficiencies
Chlorine is a relatively mobile nutrient, which means it moves around freely within a plant, going wherever it is needed. This means that deficiencies are most often seen in older growth. Chlorine deficiencies appear as wilting, leaf mottling, and a highly branched but stubby root system. [Cabbages that are grown in chlorine deficient soils do not smell like cabbages.]
More often, chlorine toxicities occur close to swimming pools and in areas with hard water. [San Jose tap water ranges in pH from 7.0 to 8.7.] Symptoms of chlorine toxicity appear as scorched leaf margins, excessive leaf drop, reduced leaf size, and reduced overall growth. Too much chlorine can also interfere with nitrogen absorption, causing chlorosis, or yellowing, but that might not always be a bad thing.
We know that new growth tends to be more susceptible to disease than older growth. It ends up that chlorine’s interference with nitrogen uptake may be a method of reducing disease severity. As a disease occurs, plants absorb more chloride anions, blocking nitrogen uptake, and reducing the amount of vulnerable new growth being produced.
Now you know.
You can grow a surprising amount of food in your own yard. Ask me how!