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Looking Ahead

Forages & Grains

Corn

Soybeans

Fruits

Vegetables

Nursery & Forest

Degree Days

Looking Ahead
Volume 60 Number 19 Date 08/27/2015


CORN EARWORM - The first significant migration of the 2015 season was documented from August 20-26 in Columbia, Dane, Dodge, Green Lake, Fond du Lac, Rock and Vernon counties, where 1,726 moths were registered in 11 pheromone traps. The weekly high count was 535 moths per trap near Markesan in Green Lake County. This late-season flight ensures that egg laying has intensified and the risk of damage to sweet corn will persist into September.

CORN ROOTWORM - Preliminary results of the annual beetle survey show population increases in south-central and north-central Wisconsin and a minor decrease in beetle abundance in the southwest region. District averages thus far range from 0.1 beetle per plant in the northeast to 0.8 per plant in the southwest. The state average in 140 fields surveyed as of August 26 is 0.6 beetle per plant. A count of 0.75 or more beetles per plant in continuous corn indicates a heightened risk of root damage to non-Bt corn in 2016.

WESTERN BEAN CUTWORM - On the basis of pheromone trap counts, the moth flight peaked one week later and was 23% larger than that of 2015. The cumulative seasonal capture was 639 moths in 96 traps (seven per trap), which compares to 521 moths in 108 traps in 2014 (five per trap) and 663 moths in 114 traps in 2013 (six per trap). Infestations resulting from the flight are generally light, although cutworms have been found in an estimated 1-6% of the ears in a few individual fields since mid-August. The larvae observed this week in the west-central and northwest counties were in the intermediate to late development stages.

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 serious infestations. 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.

SOYBEAN APHID - Densities statewide were the lowest since 2012. According to the annual survey finalized earlier this week, the state average aphid count increased from 15 per plant during the July portion of the survey to 33 per plant in August. The August counts suggest that insecticidal control was generally unwarranted for most Wisconsin soybean fields this season, although a small percentage of fields did develop economic populations and were treated to reduce aphid pressure.

-- Krista Hamilton, DATCP Entomologist