Forages & Grains
Volume 57 Number 10 Date 06/14/2012
POTATO LEAFHOPPER - Reproduction has intensified with the recent hot weather. Surveys this week found counts of 0.5-2.5 per sweep in the central and southern counties, with an average of 1.3 per sweep. Nymph and adult counts have surpassed the economic threshold of 2.0 per sweep in a small percentage of Juneau, Richland and Sauk County alfalfa fields. Routine monitoring is advised since counts are still variable and not uniformly above the treatment threshold of 1.0 per sweep for 8-11 inch alfalfa and 2.0 per sweep for alfalfa 12 inches or taller.
ALFALFA WEEVIL - Larval counts have declined to less than 0.4 per sweep and new adults are appearing in alfalfa, indicating that the weevil season has ended for much of the state. Isolated problems could persist for another week in north-central and northeastern alfalfa fields. Continued scouting is recommended for these areas.
PLANT BUG - Numbers in alfalfa remain well below the economic threshold of 5 per sweep. Counts ranged from 0.1-2.7 per sweep in Grant, Iowa, Juneau, Monroe, Sauk and Richland counties, with an average of 0.9 per sweep.
VARIEGATED CUTWORM - This insect continues to be a problem across the state. Reports of larval activity in alfalfa were received from Fond du Lac, Manitowoc, Waupaca and Waushara counties in the past week, although many northern Wisconsin fields are also at risk of infestation. Treatment is warranted if alfalfa regrowth fails to properly green up and 2 or more larvae per square foot are detected.
--Krista Hamilton, DATCP Entomologist