Kelly Jackson
Christian County Extension Office
Flooded Landscapes May Increase Certain Pests
Prolonged rain may lead to higher populations of certain pests, especially in the landscape. Here are a few to look for.
Crane flies are gangly-legged delicate flies in a variety of sizes that are common in the spring. They resemble mosquitoes but do not bite or feed at all. Crane flies can be seen resting on surfaces or flying slowly across a lawn.
The gray larvae or immature stages resemble cutworms but there is no distinct head and no legs at all. Several pairs of fleshy lobes can be seen at the end of the abdomen. They develop in wet, shaded areas where they feed on decaying organic matter such as accumulations of wet leaves or heavy thatch. The larvae are most commonly seen during spring and fall rainy periods when they are driven out of low area by excessive rain and can be caught on surfaces such as sidewalks and driveways.
Neither crane fly larvae nor adults are harmful. However, large numbers of larvae in an area are indicative of chronic wet areas or a build-up of organic matter.
Fungus gnat larvae are found in the same type of situations. These legless larvae have distinct, shiny black heads and white to clear bodies. Groups of them may form into a column and crawl across the ground like a snake.
Also, crayfish mounds may begin to appear in areas where they usually are not seen because of the high water table. They dig tunnels from 1 to 5 feet deep or to the water table so that they can stay moist. These omnivorous scavengers create "chimneys" made of mud balls that are excavated and rise above the tunnel. Because crayfishes breathe with gills, they must always maintain some degree of contact with water. There are no pesticides registered for crayfish control.
Springtails, small, wingless insects that hop, can be very abundant in humid or moist areas in landscapes or around foundations where they feed on fungi and bacteria that grow on decaying plant material. Springtails can enter homes from around the foundation, entry doors, or openings to basements or crawlspaces.
Springtails can temporarily invade homes or buildings but soon die in dry air. However, under humid conditions they can survive indoors for some time. While harmless, they are a nuisance and a persistent infestation may follow flooding or problems with moisture leaks or condensation. Infestations in limited areas can be killed by misting with a weak concentration of dishwashing soap in water; this kills the insects by direct contact and does not leave a residue. This should end temporary problems but is not sufficient for persistent infestations.
