Due to the shortage of rain this year, it seems bees and wasps are especially attracted to the areas with the most moisture, University of Illinois Extension horticulture educator Candice Miller said. Bees are attracted to the garden because of their need for sugar, but they also need water, which they use to cool their hive.
Cicada killers and yellowjackets are the most likely wasps to see this time of year. Yellowjackets are 1/2-inch-long, black-and-yellow-banded wasps. They live in places such as underground nests, woodpiles, hollow trees or holes in the wall of a building. Yellowjackets are easily provoked and can sting more than once. They may attack in force if their nest is disturbed.
Usually, insects are busy collecting supplies for their nests and are completely uninterested in humans. They will only react if disturbed. Leaving them alone and moving away slowly is a good strategy.
Yellowjackets often nest below ground with an opening near surface rocks, landscape logs or beneath shrubs. Some social wasps and hornets nest in hollow spaces in trees, toy chests and similar places. Seeing them regularly fly to and from a specific spot in the yard suggests a nest. Avoid the area until the presence of a nest can be confirmed and treated.
Sweat bees and other insects often land on the skin. Brushing them off is better than slapping them, which often results in a sting.
Sweet drinks and food attract bees and wasps. Keep food and drink covered. Clean up sticky spills quickly.
Sandboxes, especially when used infrequently, provide loose, well-drained area that ground-nesting bees and wasps prefer. Thoroughly disturbing the sand every couple of weeks should make the area unsuitable.
Wasps and hornets are valuable predators of insects, so we shouldn’t indiscriminately wipe them out. If a wasp colony is in an area where you can simply avoid it, do so. Mark the spot and just stay away. The nest will be abandoned in the fall and can be safely removed in the winter or, if left alone, will break up.
Active nests causing problems can be destroyed with an insecticide. Applications are best made during late evening or cool periods in early morning, when the wasps do not readily fly and most foragers have returned to the colony.
A variety of insecticides are sold for this purpose. Many combination products that include a fast-acting, short-lived ingredient with an insecticide. Care should be taken when applying insecticides and the label should be read thoroughly. Dealing with established wasps and hornets is best left to professionals.
Call the Master Gardeners at the DeKalb County Extension Office at 815-758-8194 with questions.