Introduction
The wasp is a common sight in urban and rural areas throughout North America and is the most common stinging menace in many Canadian cities.
Several thousand people are stung by these venomous insects each year. In some cases, severe allergic reactions to the venom have resulted in death.
The Biology and Lifecycle of Wasps
Wasps are classified in the group Vespoidea , and the most frequently
encountered ones belong to the genera Vespula , Dolichovespula ,
and Vespa (yellow jackets and hornets). These pests are medium sized
(10 mm-25 mm), and are readily distinguished by the bands of black and yellow
or white on their abdomens. The most aggressive species encountered is Vespula
germanica (Fab.) (German yellow jackets). These wasps have a habit of
scavenging in city garbage cans.
In early spring, the hibernating queen emerges from cracks, crevices or tree
bark to look for a new nesting site. Once found, she builds the first few paper
cells and lays a single egg in each cell. These new workers and future workers
will take over all the colony duties such as feeding and tending the queen,
tending the new larvae, scavenging for food, building new brooding cells, and
cooling the nest on hot summer days. In late fall, the colony reaches from
1,000 to 30,000 individuals. There may be more than one colony in any given
area.
As the weather turns colder in the fall, the queen usually abandons the nest
to look for a hibernating site. The workers also abandon the nest and eventually
they all die.
Physical Control of Wasps
If the location of the nest does not present a health hazard, it is best to leave the nest until November-December when it has been abandoned. The nest can then be removed and disposed of with minimal risk. If the nest must be removed when the wasps are active, the removal procedure should be carried out during the evening when wasps are least active. Depending on the location and structure of the nest, removal can be as simple as enclosing the nest in a plastic bag and detaching the single anchoring stalk from the supporting tree branch or structure. Remember to always wear protective clothing and a head net if possible.
Chemical Control of Wasps
Treating the nest with an insecticide such as propoxur or pyrethrins is an
effective means of wasp control. Spraying after nightfall is usually preferable
because wasps are less active at night. The use of a red filter over a flashlight
will provide visibility without increasing wasp activity. Always wear protective
clothing when using pesticides.
Be sure to read Proper Use of Pesticides.
What to do if you are stung by a wasp
Stings can be soothed with ice packs or with a bicarbonate-of-soda paste. A
wasp's venom is very potent. Some people have allergic reactions WHICH
REQUIRE medical attention. If the effects of a sting are severe, a doctor
should be consulted promptly
EFFECTIVE ANTI-VENOM SHOTS CAN REDUCE THE INCIDENCE OF SEVERE
REACTIONS IN VULNERABLE PEOPLE.
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