Dr. Kevin Korus: Managing for mole crickets

Mole crickets are a common pest of turf, vegetables and forages in Florida. These ground-dwelling insects tunnel through the landscape and feed voraciously on the roots of plants. Grasses are the preferred host, but common vegetable plants like beet, cabbage, carrot, cauliflower, eggplant, kale, lettuce, onion, sweet potato, tomato and many others can be affected as well.

Plants that are fed on by mole crickets will appear chlorotic and stunted. Turf will develop dead patches and can be pulled up readily. Most of the damage occurs on the below-ground parts of the plant, although the crickets can feed on the base of stems as well. The roots of affected plants will be sparse or even nonexistent. Mole crickets tunnel through the soil near the surface, and their raised tunnels can be seen on undisturbed, bare soil. Although the crickets are active year-round, they are most damaging during spring and fall.

There is an easy way to diagnose whether mole crickets are the cause of your turf or garden plants’ poor performance. In your lawn or garden, mark off a 2-foot-by-2-foot square in the soil. Add 2 tablespoons of dish soap to 1 gallon of water. Poor the entire gallon of soapy water over the 2-by-2-foot square. Set a timer for three minutes and count how many mole crickets come to the surface. If three or more crickets emerge, treatment is warranted. For help identifying mole crickets, see UF/IFAS EDIS document IPM-206 “Mole Cricket IPM Guide for Florida.”

Adult females have wings and can fly long distances at night. This means that fields with no mole crickets can become infested by adults that fly in. Unfortunately, there are very few options available for controlling mole crickets. Insecticide sprays are ineffective, but insecticidal baits can be effectively used. Baits containing the active ingredient carbaryl have been shown to provide control. However, the baits must be placed in the turf or garden when the mole crickets come to the surface. This occurs during rain, so the bait must be applied to the landscape prior to a rain event. There is a biological control agent called the larra wasp (harmless to humans) that parasitizes and eventually kills the crickets. However, the level of control depends on the number of wasps available in the environment. There are flowers (spermacoce verticillata and chamaecrista fasciculata) that can be planted in the landscape that attract the wasps. Biological control via the larra wasp is limited, and baits should be considered if damage is severe.

For more information about mole crickets and how to control them, visit bit.ly/molecricketsa and bit.ly/molecricketsb.

— Dr. Kevin Korus is the Agriculture and Natural Resources Extension Agent for UF/IFAS Extension Alachua County. Contact him at kkorus@ufl.edu or 955-2402.

This article originally appeared on The Gainesville Sun: Dr. Kevin Korus: Managing for mole crickets