September 18, 2015
Ignore Nuisance Insects
It seems like a lot of bugs are bugging a lot of people recently! You may have been annoyed by a swarm of tiny, white winged insects... or you may notice large beetles devouring ripe tomatoes or overripe fruit... or had caterpillars forming large, ugly webs on the tips of branches in trees.
While nuisance insects may be difficult to ignore, waiting for them to move on is often the best course of action. Due to the growing need to protect beneficial insects and pollinators, applying an insecticide to control a nuisance insect is not responsible pesticide use, cost effective, and frequently will not solve the problem.
The little white, flying insects are most likely woolly aphids. Female woolly aphids hatch from overwintering eggs in spring. After one to two generations on a primary host plant, new aphids develop wings and fly to a secondary host.
During summer feeding, woolly aphids appear as fluffy white masses on plant stems or leaves. This generation does not have wings. In late summer, another winged generation is produced. These white winged adults swarm and fly to a primary host plant to lay eggs for overwintering.
Insecticide applications are not needed or recommended at this time. Swarming will stop and the nuisance will end. If woolly aphid control is needed on a specific plant, this needs to be done next season and only if large masses of white woolly aphids are found on a plant.
If you notice large brownish beetles feeding on ripe or overripe fruit, these are likely bumble flower beetles, also known as brown fruit chafer. They are about three-fourths inch long, mottled yellow/brown, and have thick layer of fine hairs on their thorax.
Adult beetles emerge in late summer and feed on rotting fruit, corn, sap, and other plant juices. They sometimes cause damage to flowers. Prompt harvesting ripe fruit and removal of overripe, damaged or rotting fruits will reduce their population. Hand-pick adults and drop into soapy water if feasible. Chemical control is not necessary and cannot be applied to ripening fruit because of safety.
If you see large, ugly webs filled with caterpillars near branch tips of trees; don't be overly concerned. Insect feeding on tree leaves this late in the season is not very harmful to otherwise healthy, established trees.
These are fall webworm and they are feeding on leaves that will soon die and drop from trees anyway. The loss of some foliage is not harmful enough to warrant a pesticide application that will also kill beneficial insects.
If webworms are on a stressed or newly planted tree, reduce feeding by knocking the nest out of the tree with a rake, broom or by hand. If the webbed nest is too high in the tree to do this safely, try using a nozzle on a garden how to break up the web. If you choose to ignore fall webworm on established trees, birds are likely to provide some caterpillar control for you.
Other nuisance insects are the ones that make their way into homes as cold weather arrives. These usually include flies, crickets, boxelder bugs, and Asian lady beetles. For these insects, tight fighting windows and doors, screens in good repair, and caulking of cracks and conduits is the best means to reduce the number of insects accidentally finding their way indoors.