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Forages & Grains
Volume 59 Number 17 Date 08/28/2014 POTATO LEAFHOPPER - Surveys conducted in Dane, Green, Richland and Sauk counties during the last week of August found non-economic populations. Counts were below 1.0 per sweep in all fields sampled and the average was only 0.3 per sweep. Nymphs are appearing less frequently in sweep net collections and significant population increases are unlikely to occur during the remainder of the growing season. PEA APHID - Counts have escalated in individual fields. Several alfalfa fields surveyed in Richland and Sauk counties contained 4-6 per sweep, the highest populations documented in several weeks. Other sites had fewer than two per sweep. Pea aphids have been of minor importance this year. GRASSHOPPER - This pest remains abundant in the grassy areas adjacent to alfalfa, but minimal feeding injury is evident beyond the field margins. Alfalfa fields with counts in excess of 3-4 per sweep are not unusual in portions of western Wisconsin. ALFALFA CATERPILLAR - The adult stage of this insect is fairly abundant in alfalfa in the southern two-thirds of the state, suggesting an increase in larvae may occur by early September. Severe alfalfa caterpillar damage is rare, but results when large numbers of female butterflies oviposit on recently cut fields and the emerging larvae defoliate the regrowth. -- Krista Hamilton, DATCP Entomologist 
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