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Forages & Grains
Volume 62 Number 12 Date 07/20/2017 POTATO LEAFHOPPER - Alfalfa fields surveyed in Chippewa, Columbia, Dane, Dunn, Iowa, Jackson, Monroe, Richland, Sauk and Vernon counties in western and southern Wisconsin contained 0.1 -2.2 adults and nymphs per sweep, with an average of 0.7 per sweep. Economic populations above two leafhoppers per sweep (for 12-inch alfalfa) were not as prevalent this week as in the previous week. The relatively high proportion nymphs in most fields indicates significant reproduction is occurring and populations are likely to increase in alfalfa and on fruit and vegetable crops this month. PEA APHID - Levels of this insect remain very low at less than 0.5 aphids per sweep in all surveyed fields. The July 13-19 average of only 0.2 per sweep is nearly unchanged from 0.3 per sweep recorded the week before. PLANT BUG - Mixed populations of alfalfa and tarnished plant bugs currently average 0.6 per sweep across the lower two-thirds of the state, with a range of 0.2-1.8 per sweep. The week's highest count was noted in Monroe County. Nymphs are generally more abundant than adults at this time. ALFALFA CATERPILLAR - Larvae are prevalent in field collections, especially in southern and western alfalfa fields where counts occasionally average 0.2 per sweep (20 per 100 sweeps). Adults are also common in alfalfa, signaling that egg laying is occurring and more larvae should appear soon. -- Krista Hamilton, DATCP Entomologist 
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