Eastern Tent Caterpillars are Here

As a young boy growing up and visiting my grandparents, I can remember seeing little webbed tents in my grandfather’s apple trees. He would tie handfuls of sage grass into a torch and burn them out before they could defoliate his apple trees. If they were not controlled in time the could completely defoliate the trees. The trees could grow new leaves, but the defoliating would affect the apple crop. They also are found on wild cherry, crabapple, hawthorn, maple, peach, pear and plum trees.  I was warned not to handle the hairy worms because they might sting, but these were not stinging caterpillars. I was soon shown by the older kids how to hold and allow the caterpillars to crawl on my hands.

The caterpillars hatch from shiny, black egg masses that were glued to small pencil sized twigs. The egg masses encircle the branches and the caterpillars begin to hatch in early March. While feeding for 4 to 6 weeks the caterpillars grow to a length of 2 to 2 ½ inches.  The larvae are black with a white stripe down the back, brown and yellow bands along the sides, and a row of oval blue spots on the sides. As the caterpillars grow, they enlarge their web, eventually it will be more than a foot in length. The larvae remain within the tent during the heat of the day and during rainy weather. They emerge to feed during the early morning early evening and at night when it is warm enough to do so.

When they reach maturity, the larvae begin crawling on plants, sidewalks, drive ways and on the sides of houses. The phone calls begin. If the defoliation has not been excessive, the webs in the trees often go unnoticed. When the whole yard is crawling with black caterpillars with racing stripes, people notice. By this time the damage has been done, and the larvae are seeking a protected place to pupate. We also get calls about the tiny cocoons on shrubs, the side of houses, in flower beds and other sheltered places. The adult moths will emerge in about 3 weeks, they are about an inch long. They are reddish-brown in color with two diagonal pale strips across the fore wings. After emerging they mate and the females attach the egg masses to the branches, to begin the cycle the next spring.

Removing the egg masses during the winter is one of the best management tools. While the tents are still small in the early spring they are easy to remove and destroyed by hand. Larger tents may be wound upon the end of a stick and pulled from the tree. The webbing, shelters the larva from insecticidal applications and the tent must be torn open or saturated with water before the application can penetrate the web. Parasitic wasps are important predators of the tent caterpillars and greatly reduce the populations in some years. Other insect predators and a few diseases also help to regulate the eastern tent caterpillar populations.

Termite Swarming Season Is Here

The season has arrived when my office will be filled with small envelopes, medicine vials, fruit jars, cups and plastic bags containing very small winged insects. These containers will be brought by very nervous people who will want to know if their houses are threatened by these tiny insects. Termite swarming season is here, and tiny gossamer winged insects can be seen flying in small clouds. If you are unlucky these insects will be found flying within your house, emerging from tiny holes in your wall. More unnerving is to find small clumps or sprinklings of tiny insect wings upon the window sills of your home. Unfortunately if this is the case, it means that the termites have been active within the structure for three to five years. For termites to live is to eat and to eat means wood is being consumed and structural integrity is being threatened. Formosan Subterranean Termites colonies can consume up to a thousand pounds of wood a year due to the large number of termites within their colonies. Native subterranean termite colonies are much smaller and the damage they cause occurs at a slower rate.

     Confusion reigns because the ants that are swarming this time of year are very similar in appearance to termites. Both are of similar size and shape and color, both have four wings, six legs and antenna. Closer inspection will reveal differences that can be seen without a magnifying lens. Both have four wings, but the termites wings are of the same length and shape. The front wings of the ant are longer than the back wings. The body of an ant has a pinched waist with the same appearance of a wasp and the body of the termite is the same width for its entire length. The antenna give the final proof, the first segment of an ant’s antenna is long and is followed by much shorter segments. This arrangement gives the ant’s antenna an elbowed appearance that is very distinctive. The antenna of the termite is much like a string of pearls.

     Native subterranean termites are tied to the ground by their need to live within a high moisture environment. This is a weak point in their biology that can be exploited to control them. Most termite treatments involve putting a barrier of insecticide on the ground that will prevent the termites in the ground from entering the house. Termites trapped within the structure are cut off from their moisture supply and will soon perish. Termites gain entrance to house through cracks and crevices or by building mud tubes up the outside of the concrete slab upon which the house is built. These are easy to spot and when broken open the active termites are exposed going up and down the tube. The mud tubes will generally be the size of pencils and will cross the outside of the concrete slab toward some opening in the brick or exposed wood. These tubes may be obscured by tall grass, vines, ornamentals, mulch, or debris. All of these things should be kept away from the slab to prevent termites from entering the house unnoticed. Cracks in the slab may be an undetectable point of entry. The square cut out in the slab that lies beneath most bathtubs is the most common place for infestations to begin. There should be an inspection plate in a closet or wall behind the tub that allows inspection of the pipes entering the house. Once termites have entered a house they not only eat the wooden studs they will also feast on the paper covering of the gypsum boards. They will tunnel through the boards and eat the paper underneath the paint on the walls then cover the hole with mud. Wiping a white cloth across the wall will result in streaks when the mud is removed revealing holes in the wall.   

     To protect your property you should visually inspect the outer walls of your slab each year along with all the hidden areas that are accessible to visual inspections. Continue to be alert for and tell tale signs of mud on the walls of your home that may mean termites are already present and damaging your home. Even after your house has been properly treated it is necessary to continue to inspect your house for termites. Broken pipes, digging animals, cracked slabs and other unforeseen circumstances can again put your house at risk to termite infestation.

Varroa destructor

With a name like Varroa destructor you would expect the organism to be a problem causer, and it is. This mite virtually single handedly wiped out all feral honey bee colonies in many areas of the United States. These small (0.06 inches wide) mites feed on both adult bees and developing honey bee larvae. Adult mites lay eggs in the cells of the developing bee larva resulting in the death, deforming or seemingly no visible affect on the larva. After the bee matures the mites will also ride the adults feeding on the hemolymph. The mites also serve as transmitters of several virsuses that may kill the bees or compromise their immune systems.
Economic thresholds for mite infestations have been set for different sampling methods. If 10 mites are found on 200 bees by the sugar shake method control measures need to be taken. The sticky board method measures mites that fall to the bottom of the colony and become suck there, the boards are removed after 24 hours and the mites are counted. Colony size will then determine if the number of captured mites requires control measures be taken when counts exceed 60 to 190 mites.
Much work has been done on control measures and new alternatives are now available. Pesticide strips hung between the wax combs have provided high levels of control, but in some circumstances the mites are becoming resistant. Mechanical control measures do not use chemicals and may not be as effective in ruducing mite numbers but they do not use chemicals to control the mites. Screened bottom boards are benefical in reducing numbers of mites within the colony, but are not a stand alone treatment. Using drone-brood as a trap crop can dramatically reduce mite populations. Mites prefer feeding on the larger drone larva, and special combs with drone sized cells may be inserted within the hive then removed before the mites emerge. Covering the adult bees with powdered sugar can cause mites to loose their grip and fall off their host.
To me the most exciting advances are in honey bee genetics. Particular strains of honey bees are more tolerant to the mite because of a different behavior or physiological trait. Russian bees have been exposed to the mite for a number of generations and are more than twice as tolerant of the mites as the typical U.S. strains. Queens are being selected that show high levels of hygienic behavior toward varroa-parasitized pupae. The bees bred for brood-nest cleanliness significantly reduce the need for control methods.
Biopesticides are being registered for the control of the varroa mite. These naturally occuring organisms or their by-products are showing control efficacy equal to conventional chemical controls. One product uses a combination of essential oils within a vermiculite tablet to treat both varroa and trachael mites. Another is derived from tobacco plants and is sprayed on the adults as they emerge from the brood comb. Formic acid has been used by beekeepers in Canada and Europe for years to control mites during cooler weather (under 79 degrees) and when honey isn't flowing. Care must be taken with smaller hives, lest the bees be overwhelmed by the fumes.
Synthetic insecticides are still capable of giving up to 100% control of the varroa mites, but continual use can lead to resistance. State Departments of Agriculture have approved lists of products that may be safely used within the hives and only these should be used.