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Forages & Grains
Volume 60 Number 11 Date 07/02/2015 POTATO LEAFHOPPER - Counts in alfalfa are increasing but remain below established economic thresholds. Surveys conducted in Calumet, Clark, Columbia, Dane, Grant, Iowa, Outagamie, Vernon, Winnebago and Wood counties found a range of 0.1-1.2 adults and nymphs per sweep and an average of 0.6 per sweep. Nymphs are appearing in more fields, indicating a potential for populations to increase this month. ALFALFA WEEVIL - A few late-stage larvae persist, but most of the population has pupated and new adults are appearing in sweep net collections. Larval counts in second-crop alfalfa have been reduced to less than 0.05 per sweep, and no further problems are anticipated this year. PEA APHID - Numbers have not changed significantly since the last report. Sweep net counts in fields surveyed as far north as Clark County are still very low and average less than 0.4 per sweep. Pea aphid levels have shown a considerable decline since mid-June. Small Grains CEREAL LEAF BEETLE - Defoliation of wheat has been observed in the last two weeks in Columbia, Dane, Rock, Sheboygan and Winnebago counties. In Dane County, it is reported that 10-25% of the flag leaves were damaged in several fields. Although most of the infestations were minor and yield loss was not expected, it is recommended that crop advisors and growers increase scouting efforts and consider control for populations of three larvae per plant for grain that has not reached the boot stage or one larva per flag leaf when grain is heading. Larval CLB development is brief and requires about 10 days to complete. Peak larval feeding may have already occurred in southern and eastern Wisconsin. -- Krista Hamilton, DATCP Entomologist 
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