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Looking Ahead

Forages & Grains

Corn

Soybeans

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Degree Days

Looking Ahead
Volume 59 Number 11 Date 07/17/2014


WESTERN BEAN CUTWORM - The annual flight is slowly accelerating across southern and central Wisconsin. Pheromone traps registered moths at 13 of 98 monitoring sites, with a high count of seven moths near Arlington in Columbia County. Emergence is approximately 10-25% complete in the southern half of the state. Egg deposition on corn and dry beans is occurring at advanced locations.

EUROPEAN CORN BORER - Pupation of first generation corn borers has started in the south-central and southwest areas. Black light traps could register the earliest moths of the summer flight by July 20. Larvae from the spring flight presently range in development from second to fifth instar. The treatment window for first generation larvae has closed over the southern two-thirds of the state with the accumulation of 1,100 degree days (modified base 50°F).

SPOTTED WING DROSOPHILA - Additional flies have been trapped in Dane, Door, Iowa, La Crosse and Rock counties since the last report, bringing the total number of counties with confirmed SWD detections this season to six. The first flies of 2014 were captured in Vernon County on June 30 by UW-Madison researchers. The appearance of SWD should be viewed as an early warning to fruit growers to increase monitoring efforts (checking traps twice weekly), install barrier netting, or make preparations for possible insecticidal control. The use of insecticides is not advised until SWD infestation is verified by trapping or visual inspection.

SOYBEAN APHID - The first economic infestations of the year may develop before the end of the month. Densities have increased to moderate levels in a few Dane and Sauk County fields, although the typical average is less than five per plant. Historically, the first economic populations of 250 or more aphids per plant have been detected in Wisconsin by the third week of July. This pest requires consistent monitoring from now until the R5.5 stage of soybean growth in August.

STALK BORER - Larvae ranging in size from ¾-1¾ inches were noted to have caused extensive damage to the peripheral rows of corn at a few sites in Dane, Richland and Vernon counties. In one Dane County field, 43% of plants in the third row from the edge were severely damaged. Spot treatment is no longer advised now that larvae have bored into the stalks and unemerged tassels, and most corn is beyond the susceptible V7 growth stage.

-- Krista Hamilton, DATCP Entomologist