YELLOWJACKETS

DoD PESTICIDE HOTLINE

Most people know and fear the yellow and black striped yellow jacket wasps that are common, uninvited guests to late summer picnics. Their stings are painful and for those people allergic to insect venom, they are dangerous. Many people confuse bees, which are fuzzy and only feed on flower nectar, with wasps, which have shiny bodies and are predators. What most people don't realize is that yellow jackets capture enormous numbers of flies, caterpillars and other insects to feed their young. They have been seen bringing in more than 225 flies an hour to a single nest; one study found that over a three day period, just two wasps collected 20 grams of imported cabbage worms. It is usually only in late summer, when their populations are at their peak and wasps are attracted to plants with ripening fruit or aphid honeydew deposits on the leaves that most conflicts arise between humans and yellow jackets. Although they are touchy defenders of their nests, most stings are a result of accidentally trapping or pinching a wasp.

Between 0.4 and 0.8 percent of humans are allergic to social wasp and bee venom. Nearly 80 percent of all serious venom-related deaths occur within one hour of the sting. If symptoms are more serious than localized swelling, reddening and pain or mild headache and fever, a physician should be consulted. Multiple stings are especially dangerous. Some people may develop sensitivity to venom after repeated stinging episodes over a short or long period of time.

You can avoid being stung by following a few rules:

Remove all outdoor food sources attractive to wasps. Feed pets indoors and keep garbage cans tightly covered and wash cans regularly to remove spilled food. Bury fallen fruit and table scraps deep in compost piles and don't compost meat scraps or bones.

Watch where you sit or step (don't go barefoot!). Be especially careful to look before reaching into berry bushes or picking fruit. Thirsty wasps are attracted to moisture so be cautious when sitting on or handling wet beach towels.

Never swat at a yellow jacket hovering around you--it is a good way to get stung. Instead, quietly move away or let the wasp leave of her own accord. The only exception to this is if you have accidentally disturbed a nest and hear wild buzzing. In this case protect your face with your hands and RUN!

Pick fruit in the early morning or evening while it is cool and most wasps are still in their nests.

To reduce yellow jacket problems at picnics and barbecues:

Minimize the length of time food is available by keeping it tightly covered until just before it is to be eaten. Clear away scraps and dirty plates as soon as the meal is over.

Serve sweet or alcoholic drinks in covered cups with drinking straws through the lids so wasps can't get inside and then sting you in the mouth as you drink. When drinking out of a can, keep the opening covered with your thumb between sips.

Some yellow jackets and hornet species scavenge for meat in addition to preying on live insects. Others are attracted to the sweets and sugars of candy wrappers, soda cans, and pastry deposited in garbage cans. These local populations can be reduced by removing the waste frequently and maintaining tight lids on all trash receptacles. Pesticide strips containing dichlorvos (Vapona or No- Pest Strip), attached to the inside of garbage can lids, will also help to reduce both fly and yellow jacket presence.

Set up baited yellow jacket traps around the edge of the picnic area or on the end of the table to attract wasps away from the food to capture them. Small disposable cardboard traps or reusable ones made of wood and metal screen are sold at garden centers. They work by attracting wasps to bait placed under an inverted funnel. When the wasps have had their fill and instinctively fly upwards toward the light at the end of the funnel, they are trapped in an enclosed chamber above. One can buy any variety of ready-made traps with a wide range of effectiveness. The following two companies (among others) have produced successful traps:

Seabright Laboratories, 4026 Harlan Street, Emeryville, CA 94608, (800) 284-7363 or (415) 655-3126

Sterling International, Inc.

P.O. Box 220

Liberty Lake, WA 99019

(800) 666-6766

[FAX: (509) 928-7313]

In early and midsummer, 1-2 traps should be enough for most picnics. In August and early September, however, 6 or more traps might be necessary. For much of the season, the best baits are Spam, ham, fish, cat food or meat scraps. Later in the summer, when wasps need less protein because they aren't rearing their young, sweet baits such as jam, honey or rotting fruit are often more attractive. Make very sure they are dead before cleaning out reusable traps.

One can also construct a simple and safe trap at virtually no cost - an example follows. Start with a one gallon translucent milk bottle. With a razor blade, cut a couple of small slits downward from one point (three quarters of an inch across at the bottom), a little more than halfway up the sides. Bend the point so formed inward. Fashion part of a wire coat hanger into a hook at the bottom and thread it through a small hole punctured into the cap so that the hook will be down about halfway to the bottom of the bottle when inserted. Bend the top of the coat hanger piece so that it can be suspended from the lid. Fill the bottle about one-third full of soapy water. Then pierce a small piece of turkey ham, salami, or ham (small enough to go through the bottle opening) with the hook and put the lid, hook, and meat in place in the bottle's neck. Hang the bottle in a tree or bush upwind from the area where wasps are not wanted. You might also dig a hole and place the bottle in the ground so the downwind opening is at ground level (wasps often search along the ground for food). If no gallon bottles are available, a one-liter transparent soft drink bottle should suffice.

Although the number of yellow jackets in late summer invariably prompts many concerned inquiries on how to control them, usually there is little that can be done. The wasps will all die in a matter of weeks as fall approaches. Even if a nearby nest is discovered late in the summer, eliminating it may not have the desired effect because wasps can fly in from up to a mile away. It is never advisable to put out poison baits because children and pets may get into them and because other, beneficial, insects may take the bait and be killed. It is also a terrible idea to pour gas or kerosene into an underground wasp nest where it poisons the soil. If yellow jackets do build a nest in a location likely to cause problems with people or livestock, the best time to remove it is early in the season, while it is still small. This is a job for a very careful person or a professional pest control service. Chemical wasp sprays are available, but if you use them, consider very carefully where the stream of pesticide that misses the nest will land. Always use such products according to direction on the label. Remove an exposed nest that has been sprayed as soon as the wasps are dead. Wear rubber gloves and dispose of the nest to prevent birds from eating the poisoned larvae left inside.

Removing a Hanging Wasp Nest Without Using Chemicals

First, it is a good idea to get a helper. To be safe, both of you should wear protective clothing from head to foot. Although a beekeeper's suit with hat and veil is ideal, you can assemble a similar suit for the occasion from heavy coveralls, a hat with a wide brim and a length of fine screening. Wear boots with your pants cuffs pulled outside the boot tops and seal the cuffs around the boot top with rubber bands so that wasps can't get up your legs. Wear gloves and pull your sleeve cuffs screening over the hat (the brim should keep it away from your face) and tie it around the neck, over the collar of the coveralls. Make sure there are no openings around the collar or base of the veil. You should wear another layer of clothing underneath the overalls because wasp stingers are long enough to reach through one layer of cloth. To remove the nest, approach in the evening or at night when the wasps are all home and less active because it is cool. Have your helper hold open a large, heavy bag or a box with a tight lid under the nest while you cut the attaching stem of the nest as quickly as possible using a long handled pruning hook, or other tool. When the nest is in the bag or box, close it immediately and seal shut. Kill the wasps inside by putting the whole package in a deep freeze for 24 hr. or by directing a wasp spray into the package through a small hole for several minutes. Don't neglect this last step because wasps can eventually chew their way out of almost anything.

Wasp Nests In Walls

Never block up the opening as wasps can chew through wood or follow wiring to the interior of the house. In the fall, when the nest is definitely vacant, caulk or repair the crack to prevent recolonization next year.

Underground Wasp Nests

This is a job better left to a pest control operator, who can dig and vacuum out the nest, however, you can pour several gallons of boiling water into the nest. Wear protective clothing as described and be extremely careful not to scald yourself with the boiling water.

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