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Overwintering emergence and trapping of adult Stethorus punctum punctum (Coleoptera: Coccinellidae) in Pennsylvania apple orchards

Felland, C.M., Biddinger, D.J., Hull, L.A.
Environmental entomology 1995 v.24 no.1 pp. 110-115
Stethorus punctum, overwintering, seasonal development, adults, air temperature, heat sums, trapping, sticky traps, Malus domestica, orchards, predatory insects, ammonium carbonate, Pennsylvania
Emergence of adult Stethorus punctum punctum (LeConte) from overwintering sites in apple orchards was examined for 3 yr in Adams County, Pennsylvania. Emergence during the spring in cages placed over overwintered individuals occurred between 100 and 300 degree-days (DD) when temperature units were accumulated beginning 1 March. Fifty percent emergence occured at 210 DD5.C. Emergence was 2.3, 46.7, and 95.8% complete by the half inch green, pink, and the petal fall stages of 'Yorking' apple development, respectively. Most adults emerged on days of average, minimum, and maximum air temperatures of 15-20, 5-15, and 20-30 degrees C, respectively. Temperatures in overwintering habitat were similar to ambient air temperature. Counts in the tree canopy were highly correlated with capture in the emergence cages in a warm year, but were too low to relate to capture in the other two cooler years. Capture of adults on yellow sticky boards was an efficient monitoring method; first capture occurred at 20-30% emergence. Yellow traps were more effective than white, and addition of ammonium carbonate did not significantly increase capture with yellow traps, but inhibited capture with white traps.