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Forages & Grains
Volume 59 Number 14 Date 08/07/2014 POTATO LEAFHOPPER - Surveys continue to yield non-economic counts of less than two per sweep. Despite the dry weather of July and sufficiently warm temperatures, populations in alfalfa have remained consistently low since the first migrants arrived in the state in May. Nevertheless, weekly monitoring of the third alfalfa crop throughout August is recommended. PLANT BUG - Counts are similar to last week at 0.5-4.2 per sweep. Most fields contain approximately two per sweep, less than half the economic threshold of five per sweep. Nymphs have become more abundant in alfalfa in the last two weeks and now comprise about 40-80% of sweep net collections. PEA APHID - Populations of this forage pest could increase in response to the cooler and mostly dry weather, which usually favors aphid population growth. Counts this week were still extremely low at less than 0.6 aphid per sweep in all fields sampled. STRIPED BLISTER BEETLE - A few alfalfa fields surveyed in La Crosse and Monroe counties had low counts of 1-2 beetles per 100 sweeps. These insects can be an indicator of potentially high grasshopper populations since the immature stages are predaceous upon grasshopper eggs. Heavy blister beetle infestations often occur during or just after an outbreak of grasshoppers. -- Krista Hamilton, DATCP Entomologist 
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