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Forages & Grains
Volume 58 Number 3 Date 05/16/2013 ALFALFA WEEVIL - Larvae were observed for the first time this season on May 13 in Grant County. Surveys conducted in Dane, Green, Grant, La Crosse, Lafayette, Monroe and Rock counties found low counts of 1-19 per 100 sweeps, with an average of three per 100 sweeps. Systematic sampling for larvae and leaf tip damage should begin at 300 degree days (sine base 48°F), or by May 16 in southern Wisconsin and one week later in the central counties. Alfalfa weevil degree day accumulations as of May 15 were as follows: Beloit 272, Eau Claire 164, La Crosse 188, Madison 212, Milwaukee 172 and Wausau 151. TARNISHED PLANT BUG - Surveyed fields in the southwest and south-central areas contained very low counts of 1-5 per 100 sweeps. The average was two per 100 sweeps, the same as in the previous week. Plant bug populations rarely attain economic levels in alfalfa in spring, but their relative abundance can be an indicator of potential problems for apples, strawberries and other fruit and vegetable hosts. PEA APHID - Nymphs were collected from 34 of the 39 (87%) alfalfa fields sampled in the past week. The high count of 42 per 100 sweeps was found near Janesville in Rock County. -- Krista Hamilton, DATCP Entomologist WHEAT DISEASE - Surveys in winter wheat in Dane, Dodge and Fond du Lac counties found very low levels of disease. Powdery mildew was present in seven of 12 fields and Septoria was noted in five fields; both diseases occurred at only trace levels. Most fields were in the Feekes 4-5 range and no rust was observed. Reports from the national Cereal Rust Survey indicate significant stripe rust infection throughout the southern states, including cases within the last week from Champaign and White counties in southern Illinois. These reports, coupled with warmer weather, suggest that growers should remain alert for fungus development in their wheat. -- Adrian Barta, DATCP Pest Survey 
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