Forages & Grains
Volume 64 Number 18 Date 08/29/2019
POTATO LEAFHOPPER - Surveys conducted in western Wisconsin during the final week of August found variable, mostly non-economic populations. Counts were below 2.4 per sweep in all but two of the fields sampled (both in Vernon County) and the weekly average was 0.7 per sweep. The proportion of nymphs appearing in sweep nets has declined and significant population increases are not expected for the remainder of the growing season.
PEA APHID - Densities have escalated in localized fields. One alfalfa field surveyed in Crawford County and three in Vernon County had averages of 10-20 aphids per sweep, the highest counts documented in several weeks. Other sites had lower populations of 2-5 aphids per sweep. The mostly dry, cool weather of August has probably contributed to the late-season aphid resurgence.
GRASSHOPPER - This pest remains common in the grassy areas bordering alfalfa, but minimal feeding injury is evident beyond the field margins. Alfalfa stands with counts in excess of 3-4 per sweep are unusual in the southern half of the state.
-- Krista Hamilton, DATCP Entomologist