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Forages & Grains
Volume 61 Number 17 Date 08/25/2016 POTATO LEAFHOPPER - Late August surveys in alfalfa found only low to moderate counts of 0.2-1.6 leafhoppers per sweep, with an average of 0.6 per sweep. Levels of this insect have been below threshold all summer long, despite a timely spring arrival and very favorable temperatures. Although a few individual fields sampled earlier this month contained localized "hotspots" of high leafhopper counts, none had a fieldwide average exceeding the two leafhopper per plant threshold for alfalfa growth 12 inches or taller. PLANT BUG - Nymphs were less abundant in fields sampled this week, indicating population growth is decelerating. Counts averaged 0.5 plant bugs per sweep and ranged from 0.1-1.4 per sweep. The tarnished plant bug is the most common plant bug species found in alfalfa at this time. PEA APHID - In contrast to other alfalfa pests, aphid populations have increased slightly in the previous 2-3 weeks. The average count from August 18-24 was approximately 2.5 per sweep, although exceptional fields had averages of 6-7 per sweep. The higher counts were observed in west-central Wisconsin alfalfa. -- Krista Hamilton, DATCP Entomologist 
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