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Looking Ahead

Forages & Grains

Corn

Soybeans

Fruits

Vegetables

Nursery & Forest

Degree Days

Looking Ahead
Volume 59 Number 17 Date 08/28/2014


CORN ROOTWORM - The statewide beetle survey was completed earlier this week. Review of the data indicates that counts are generally lower than last year across much of Wisconsin, with the exception of the southwest and west-central districts. The 2014 state average of 0.4 beetle per plant represents a slight decline from 0.5 per plant in 2013. Results of the survey are summarized in the CORN section.

EUROPEAN CORN BORER - Egg deposition is expected to continue for another two weeks. The treatment window for second generation larvae has closed near Beloit, Madison, La Crosse and Sullivan, and remains open only a few more days in the southeast and central districts. Final inspections for egg masses and small larvae should be conducted before 2,100 degree days (modified base 50°F) are reached.

SOYBEAN APHID - Densities have increased to economic levels in some fields this month. According to surveys conducted from August 21-27, approximately 20% of soybean sites sampled in Calumet, Dane, Dodge, Green, Fond du Lac, Lafayette, Manitowoc, Richland and Sauk counties contained above-threshold populations of 250-770 aphids per plant. The average was 132 aphids per plant. Many fields are approaching R5.5-R6, the growth stages at which no yield benefit is gained by insecticide treatment. Late-season control is probably uneconomical for most soybeans at this point.

CORN EARWORM - The first significant migration of 2014 was noted from August 21-27 in Dane, Dodge, Green Lake and Fond du Lac counties where 2,748 moths were registered in six pheromone traps. The weekly high count was 878 moths per trap near Mayville in Dodge County. This late-season flight ensures that the risk of egg laying and damage to sweet corn will persist well into September.

LATE BLIGHT - Continued development on tomato and potato has been reported, including two new cases of the disease on potato in Adams and Waushara counties. Protective treatments of green vines with a late blight-specific fungicide on a five- to seven-day schedule should be maintained. Potato tubers remain susceptible to infection even when very little foliage is present.

WESTERN BEAN CUTWORM - The annual survey documented the lowest moth count in the last decade. The state cumulative count was 502 moths in 103 traps, or an average of five per trap. This compares to 663 moths in 2013 (five per trap) and a survey record of 10,807 moths in 2010 (79 per trap). Predictably, larval infestations in corn have also been scarce this season.

FALL PESTS - The fall invasion of Wisconsin's resident nuisance pest insects can be expected next month. Boxelder bugs, multicolored Asian lady beetles, western conifer seedbugs and, potentially, brown marmorated stink bugs are likely to aggregate on the sides of homes and buildings in September and early October as they migrate indoors for the winter. Mechanical exclusion by sealing cracks around windows, doors, siding and other openings is advised to prevent these insects from entering residences. Exterior applications of insecticides may offer temporary control of infestations when completely sealing the exterior is difficult or impossible. Applications should consist of a synthetic pyrethroid applied by a licensed pest control operator by early October, prior to insect aggregation. Under no circumstance should chemical insecticides be used indoors.

-- Krista Hamilton, DATCP Entomologist