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Forages & Grains
Volume 63 Number 3 Date 05/17/2018 ALFALFA WEEVIL - Larvae were collected from alfalfa in Green and La Crosse counties on May 15, signaling the start of the 5 to 6-week alfalfa weevil season. Surveys yielded low counts of 1-2 larvae per 100 sweeps in three of 32 sampled fields. Alfalfa weevil larvae will become increasingly common in fields and sweep nets before the end of the month, with peak activity occurring by early to mid-June. Sampling for larvae and leaf tip feeding should begin by May 21 in southern Wisconsin and May 28 across the far northern counties. PEA APHID - Recently-hatched nymphs were found in 28 of the 32 (77%) alfalfa fields sampled in the last reporting period. The high count of 52 aphids per 100 sweeps was recorded in Rock County. TARNISHED PLANT BUG - Counts of this insect are still very low at less than 20 per 100 sweeps. Plant bug levels in alfalfa in May and June are rarely of economic importance, but their relative abundance is an indicator of potential problems for other fruit, flower and vegetable hosts. The numbers observed this week suggest populations are low but increasing, and scouting of apples and strawberries is in order. -- Krista Hamilton, DATCP Entomologist 
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