Forages & Grains
Volume 63 Number 9 Date 06/28/2018
POTATO LEAFHOPPER - Counts in central and southern alfalfa fields have increased in the last two weeks, although averages remain below established economic thresholds. Surveys conducted in 28 fields during the week ending June 28 found moderate counts of 0.5-0.9 per sweep at 10% of sites, while 90% had low counts of less than 0.4 per sweep. Nymphs are appearing in more fields, indicating a potential for populations to increase to above-threshold levels next 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 declined to less than 0.1 per sweep, and further problems are not anticipated this year.
PEA APHID - Numbers average approximately 10 aphids per sweep, with a few sites containing very high counts of 20-29 per sweep. Pea aphid levels have shown a considerable increase since mid-June.
PLANT BUG - Counts in the southern half of the state range from 0.2-1.4 per sweep. The average is only 0.4 per sweep, based on surveys in 28 fields. Nymphs of various maturities can be found in most fields and reports suggest that these insects are causing damage in some nurseries, apple orchards, and in fruit crops.
-- Krista Hamilton, DATCP Entomologist