Extension Educator, Local Food Systems and Small Farms
Extension Educator, Horticulture
June 30, 2010
June 30, 2010
June 30, 2010
This is the time of year to wrap up pruning chores on evergreens. This includes both needle-type and broadleaf evergreens. If you're wondering what a broadleaf evergreen is, that includes holly, rhododendron, and azalea. The logic behind pruning your yews at this time is to allow sufficient time for regrowth to become hardened off before winter, and to keep new growth from becoming too rank before the winter months.
Pruning evergreens is part art and part science, but mostly art. A few simple rules to follow make the job results much more pleasing. Upright growing evergreens, such as pines and spruces, should not have the main leader cut off. This will destroy the natural shape, and will make the resulting growth more susceptible to breaking off. If individual branches are being cut off, they should be cut back to a bud. This will allow the bud to become the new main branch. You can also control growth direction of branches in this way. If you are growing trees for cut Christmas trees, all bets are off, as you are only dealing with trees through the first seven years of their life or so.
Make sure you use the proper equipment. Individual pruning cuts are best done with bypass loppers or pruning shears. These make clean cuts without much damage to the remaining wood. The old anvil type shears and loppers cut to a point, then crush the remaining wood. For yews, junipers, and arborvitae that are trained to a certain size of shape, you will want to use hedge shears (electric or manual) that are sharp and properly tightened. Most of these types of shears can cut up to about a quarter of an inch in size.
When pruning evergreens, remember the dead zone. This is the area toward the center of the plant that doesn't receive much light. It also has few needles or active buds. Cutting into the dead zone will cause many years (or forever) of little green growth. Also remember to prune so that the base of plants is wider that the top. This allows sunlight to hit the bottom area as well, and keeps the bottom from dying up.
June 30, 2010
It seems like the tomato is the one plant that just about everybody tries to grow. Some people grow large amounts, while others plant one or two in containers. At any rate, the calls and samples have started coming in to the office already. Most of the samples have spots, brown leaves, and dropping leaves, or all of the above. Several diseases hit tomatoes, but two of the more common ones are early blight and seporia leaf spot. Blossom end rot seems to have been running rampant on early tomatoes as well, particularly plants grown in containers and hanging baskets.
As for what to do, here is the checklist: First, keep ripe fruits picked off the plants. Second, don't work around tomatoes when they are wet. Next, you can try and improve air circulation, but if your tomatoes are severely affected you won't want to lose any more leaves. And the final step for this year is to try a fungicide. Mancozeb is probably the recommended one, but it is very hard to find. The other options are Daconil and maneb, which are easier to find but probably won't give you as good of control. The final step for future years is to practice at least a three year rotation, with good sanitation in the garden.
Blossom end rot is a non-pathogenic disease that is very common during extended dry periods. It begins as light tan water-soaked lesion on the blossom end of the fruit. The lesions enlarge and turn black and leathery. This can drastically lower the yield and lower marketability of the fruits. Fluctuating soil moisture supply during the dry periods, and low calcium levels in the fruit are the major causal factors. Control of blossom end rot consists of providing adequate moisture from fruit formation to maturity, and use of mulch (grass clippings, plastic, straw, shredded newspapers, or plastic) to conserve moisture.
June 24, 2010
Many pumpkins are already on their way, with seeds being sown a month ago. While this practice is great for producing pumpkins for pumpkin pie and blossoms, it really doesn't work very well for producing the Halloween jack-o-lantern pumpkins. The Halloween pumpkins are best planted around Father's Day. This timing helps prevent the pumpkins from rotting before we get to the end of October.
Many different varieties are available, and they come in many sizes and shapes. The small pumpkins, ranging from two to five pounds, are called "pie" types. They are normally used for cooking and fall decorations, and include the Baby Bear variety. Intermediate and large varieties are primarily used for jack-o-lanterns. Many of the newer varieties have stronger side walls to aid in display and carving. The flesh of these varieties is generally poor in quality and not used for cooking. Processing pumpkins, that are canned commercially make poor carving pumpkins, and are more like a buff colored watermelon in appearance. The jumbo or mammoth varieties are mainly used for exhibition. These jumbos can weigh in the 900 pound range. For most homeowners, you might want to pass on these since moving a 900 pound pumpkin isn't for everyone. The other option is to try and grow one in place. The "mini" varieties are usually not actually pumpkins, but they are gourds.
Pumpkins should be planted about now for carving or fall decoration. Vining pumpkins need at least 50 – 100 square feet per hill, with the larger pumpkins requiring the larger area. Hills should be five to six feet apart and rows of hills should be 10 – 15 feet apart. Each hill should have about four seeds per hill, planted about an inch deep. The miniature varieties such as the Jack-Be-Little are sometimes grown in rows with seeds planted every eight to twelve inches, then thinned to about two feet apart in the rows. Fall decoration pumpkins should be cut from the vine before the vine dries in order to have a good stem attached to the pumpkin, but after the color is acceptable.
Keep the pumpkin bed free from weeds by shallow hoeing, and make sure it is watered during extended dry periods. Major pests are squash bugs, cucumber beetles, and vine borers. Most often, frequent applications of an insecticide such as carbaryl will help protect the new runners from the vine borers and also control the beetles that transmit the wilt virus. Make sure no applications are made to open blooms, that attract the bees for pollination, by applying insecticides in late afternoon or early evening.
June 24, 2010
Master Gardeners will host their garden walk Saturday, June 26 from 9am until 3 pm. Six different gardens plus a container garden exhibit will be on the tour. The cost is $10 per person. The easiest place to start would be the Extension Office at 980 N. Postville Dr. in Lincoln. You can get your ticket there, view the demonstration beds at the office, and view the container garden exhibit. The ticket will have a map and information about the remaining gardens.
June 10, 2010
The last insect to discuss is the bagworm. Bagworms are notorious pests of evergreens such as spruce trees. We're about to June 15, the traditional date for control. With the warmer spring we may run a few days ahead of normal. The idea is to have all the eggs hatched before treatment, but not wait until the bagworms are almost mature. For control, the traditional standby has been Sevin, but the B.t. products such as Dipel and Thuricide have really taken their share of the market the past several years. The B.t. products have several good points including safety to mammals and toxicity to larger bagworms. Since they are bacteria that affect only the larvae of moths and butterflies, it does take a while for the bacteria to build up to the point where they can kill the bagworm. If you are in doubt about whether you have bagworms, check your trees and shrubs around June 15. You can actually see the small bags as the larvae build them. They become very noticeable at about 1/16 of an inch long. Treat bagworms early, since larger ones are more difficult to control.
June 10, 2010
Potato leafhopper populations have exploded in the last week. These are the small, pale green, wedge-shaped insects we often see around lights at night. The main garden crop they affect is, guess this one, potatoes. They suck sap, and inject a toxin back into the plant. The first sign is a yellow "v" at the tip of the leaf. These areas then turn brown or black. Entire plants or branches can die from these tiny insects. Control with Sevin, bifenthrin, or permethrin.
June 10, 2010
Leatherwing beetles, or soldier beetles, are now present where linden trees are pollinating. They look like pale lightning bugs, but don't have the light. These beetles are elongate, soft-bodied and about 1/2 inch long. Colors of soldier beetles vary from yellow to red with brown or black wings or trim. A common and easily-spotted species is the Pennsylvania leatherwing, which is yellow with one large black spot on each wing. Most larvae are carnivorous, feeding on insects in the soil. Larvae overwinter in damp soil and debris or loose bark. The adults are also predators, eating caterpillars, eggs, aphids, and other soft-bodied insects. They will alternatively eat nectar and pollen if no insects are around. They do not damage plant foliage. Adults are often found on flowers such as goldenrod, where they lie in wait for prey, feed on pollen and mate. Since soldier beetles are beneficial, it is inadvisable to kill them.
June 10, 2010
June 10, 2010
Apple and pear trees are also having their problems. There is a large amount of tip dieback in some varieties, and this is probably fire blight. Look for a shepherd's crook at the tip of the affected areas as a clue it is fire blight. Fire blight is a bacterial disease, therefore there is little chance for you to treat it. The common treatment in commercial operations is streptomycin, but it has to be applied before symptoms appear. Bordeaux mixture can also help prevent the disease. Prune out disease cankers when dormant. This disease cost Illinois its pear industry.
June 3, 2010
Tick numbers seem to be off the chart this year. Anyone who has been out in tall grass or wooded areas can probably attest to that. Probably, the frequent spring rains in much of the state have provided the high moisture and humidity that ticks need. Ticks are large, flattened mites that feed as parasites on mammals, birds and reptiles. They hatch from eggs into six-legged larvae that locate hosts and feed before dropping off the host and molting into eight-legged nymphs. Nymphs locate hosts, feed and drop off to molt into eight-legged adults. Adults also locate hosts on which to feed. Males may stay on the host, mating with females coming there to feed. Females engorge on blood to several times their original size, drop off the host and lay hundreds of eggs. With each tick having to find three hosts in its lifetime, many ticks starve before reproducing, although ticks can survive for long periods without food.
American dog ticks, commonly known as wood ticks, are the most common in Illinois. They feed as larvae and nymphs on small mammals, only attacking humans when the ticks reach the adult stage. Adults are reddish brown, 3/16 inch long. Females have a silver shield behind the head; males have silver, wiggly lines down the back. These ticks transmit Rocky Mountain spotted fever, a virus found here but most common in North Carolina and nearby areas. In Illinois, they also carry ehrlichiosis, producing symptoms similar to Lyme disease.
Lone star ticks feed on humans and other mammals as larvae, nymphs and adults. Larvae and nymphs are commonly called seed ticks because of their size. Walking through an area of newly hatched larvae may result in hundreds attacking your legs. Adults are about 1/8 inch in diameter, roundish and brown; females have a white spot in the middle of the back.
Blacklegged ticks, including the deer tick subspecies, also feed on people as larvae, nymphs and adults. Larvae are tiny, about the size of the period at the end of a sentence; nymphs are pinhead sized. Both tend to migrate up the legs and feed in the groin area. Adult blacklegged ticks are teardrop-shaped, reddish brown and about 1/8 inch long. The deer tick subspecies is found mainly in the northern half of the United States. Deer tick larvae feed on white-footed mice, picking up the Lyme disease, which can be transmitted to people by the nymph and adult ticks.
Ticks are numerous in areas of tall grass, where humidity is high and hosts common. Mowing greatly reduces tick numbers. When walking or working in areas of tall grass or other areas with ticks, apply a repellent containing about 30% DEET, such as Off or Cutters, to the lower legs and pants legs. If ticks are numerous in mowed areas, spraying carbaryl, permethrin, or bifenthrin should help give some control.
If a tick is attached, grasp the head with tweezers where the mouthparts enter the skin, pulling slowly and consistently. The tick will release its mouthparts and come loose. Do not handle the tick. Good luck trying to smash a tick. It's about like trying to flatten a dime with a rubber mallet. Other methods such as heat and nail polish commonly kill the tick, resulting in locked mouthparts that remain in the wound to cause infection. A tick typically feeds for 24 hours before releasing disease organisms, so remove ticks promptly when you find them.
Also pay particular attention to pets in wooded areas, or areas with tall grass. Use preventative products when possible. Carbaryl dust may be used on pets and their sleeping areas help control ticks and fleas. Mosquito and tick repellents containing DEET can be used on clothing and body parts for people. Permethrin can be used on clothing only, and not sprayed on the body. Be particularly careful of permethrin around cats and dogs, as it can be lethal.