Milling Journal - Q2 2008 - (Page 37) Army Cutworms Muster In SD Pest threat enhanced by high-value wheat. The appearance of army cutworms in wheat fields in South Dakota and elsewhere in the Plains is commonplace each spring. But extraordinarily high prices for wheat have added extra importance this year to insect control. South Dakota State University (SDSU) Extension Entomologist Mike Catangui told Milling Journal May 7 that up to 10,000 acres of winter wheat might have been infested with army cutworm in central and western South Dakota. “While winter wheat is the traditional food source for overwintering larvae, spring wheat also is endangered,” Catangui said. “Because we are planting spring wheat earlier, there is an overlap of maturing winter wheat and emerging spring wheat that are vulnerable to cutworm damage,” Catangui added. According to Catangui, previous studies at Kansas State University indicated that army cutworms can account for stand losses in wheat of up to 30%. Spraying Insecticide Catangui said the cutworms were first reported in South Dakota fields on March 27. “Since then, more than 30,000 acres of winter and spring wheat have been sprayed with insecticides for army cutworm,” Catangui said. According to SDSU, mature army cutworm larvae can reach up to two inches in length then pupate in the soil. Adult miller moths emerge from the soil from May to early June and then migrate to the Rocky Mountains in the summer to enter an inactive phase. They then come back to the plains in the fall to lay eggs on the soil. Catangui said army cutworms are not the same as armyworms. Unlike army cutworms, armyworms do not overwinter in South Dakota. Response No. 371 Armyworm moths migrate into the state starting in about late April. Armyworm larvae are therefore usually not detected until June or July. The word “army” connotes that the larvae of both insects can move en masse from field to field. There are a number of insecticides labeled for control of army cutworm. Frank Zaworski, editor MILLING JOURNAL Second Quarter 2008 37 http://www.bratney.com http://www.bratney.com
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