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Looking Ahead
Volume 58 Number 11 Date 07/18/2013 EUROPEAN CORN BORER - Pupation of first generation corn borers has started in advanced southern Wisconsin locations. Black light traps could register the earliest moths of the summer flight by July 20. Surveys indicate that larvae from the spring flight are presently in the second to fifth instars. The treatment window for first generation larvae has closed in all but the far northern counties with the accumulation of 1,100 degree days (modified base 50°F). WESTERN BEAN CUTWORM - The annual flight of western bean cutworm adults is accelerating gradually across the southern and central areas. Pheromone traps registered moths at 12 of 103 monitoring sites in the past week, with a high count of four moths near Portage in Columbia County. Moth emergence is approximately 10-25% complete in the southern half of the state. SOYBEAN APHID - The first economic infestations of the year may develop in the week ahead. Densities have increased to moderate levels of 50-142 aphids per plant (on 100% of the plants) in a few fields in Calumet, Chippewa and Fond du Lac counties, although the typical average is less than 10 per plant. Historically, the first economic populations of 250 or more aphids per plant have been detected by the third week of July. This pest requires consistent monitoring from now until the R5.5 stage of soybean growth in August. TRUE ARMYWORM - Surveys in corn across southern Wisconsin found no active infestations in the past week. Nevertheless, the second generation of larvae is developing rapidly under current high temperatures and armyworm injury should become evident before the end of the month. SPOTTED WING DROSOPHILA - Two adult specimens were collected by UW researchers in Vernon County on June 24, the first flies of the season. Additional flies have since been found in Crawford County. These detections represent the earliest recorded observations of spotted wing drosophila (SWD) in the state. Refer to the FRUIT section for additional information. -- Krista Hamilton, DATCP Entomologist 
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