Forages & Grains
Volume 64 Number 10 Date 07/04/2019
POTATO LEAFHOPPER - Counts in alfalfa have increased markedly during the latter half of June and are now above established economic thresholds in some areas. Surveys during the week ending July 4 found high counts of 2.0-4.0 leafhoppers per sweep in 14 to 24-inch second-crop fields in the central and south-central counties. The highest averages above 2.0 per sweep were recorded in Dane and Sauk counties. Nymphs are appearing more frequently in sweep nets, indicating a potential for continued above-threshold populations later this month.
ALFALFA WEEVIL - A few late-stage larvae persist, but most of the population has pupated. Larval counts have declined to less than 0.3 per sweep (30 per 100 sweeps), and no further problems are anticipated this season.
PLANT BUG - Levels in the southern half of the state are unusually low for early July, ranging no higher than 0.2 per sweep or 20 per 100 sweeps. Nymphs of various maturities can be found in most fields and, despite the low counts in alfalfa, reports suggest that these insects are causing damage in some nurseries, apple orchards, and in fruit crops.
-- Krista Hamilton, DATCP Entomologist