The western corn rootworm is an infrequent pest in sweet corn and it is restricted only to fields are continuously kept in corn production for several years. As most sweet corn fields are regularly rotsted to other crops, this is not a common pest. The larval stage of this pest is the most destructive, feeding on the roots of corn in late May and June. Above ground, infested plants may appear to be drought or nutrient stressed, making slow growth, and prone to fall over after heavy rains, making mechanical harvesting difficult. Small roots are chewed off and larger roots are tunneled by the narrow, white, ½ inch long larvae.The eggs western corn rootworm are laid in July and August in soil around the base of the corn plant. The rootworm spends the winter in the egg stage. The egg hatch begins in May and small larvae can be found in late May. The larvae grow through three instars and a prepupal stage and adults begin to emerge in late June and early July.
The adult western corn rootworm is and is yellow-brown with three prominent black stripes on the dorsum. The northern and southern corn rootworms. then but problems in sweet corn with these species is rare.
Biological control of western corn rootworm is not well understood.
Cultural: Crop rotation, alternating corn with vegetable or non-corn field crops in which the corn rootworm larvae cannot develop, is the most effective rootworm management practice in Kentucky. The more years that a field stays in continuous corn production, the more likely it will develop corn rootworm problems.
Monitoring: Adult rootworm beetles are monitored during the summer and a soil insecticide is used the following year if an average of more than one rootworm beetle is observed per plant at any time during July, August or September if the field is planted with corn the following year.
Application Alternatives :
Aztec 2.1G (tebupirimphos+ cyfluthrin) soil applied in a band, T-band or infurrow at a rate of 6.7 oz per 1000 row feet.
Force 3 G (tefluthrin) soil applied in a T-band or infurrow at a rate of 4 to 5 ounces per 1000 row feet. Force will also control cutworms when applied as a T-band at planting.
Fortress 5 G (chlorethoxyfos) soil applied in a band, T-band or infurrow at a rate of 3 oz per 1000 row feet.
Lorsban 15G (chlorpyrifos) soil applied in a band, T-band or infurrow at a rate of 8 oz per 1000 row feet.