Development of an Action Threshold and Management Strategies for Mirid Bugs on Apples 1997
Project Leaders: Arthur Agnello, David Kain, Joe Kovach, Harvey Reissig
1. Compare the efficacy of imidacloprid applied at petal fall.
2. Determine the time(s) at which damage to fruit occurs (2nd year).
3. Determine a provisional action threshold (2nd year).
4. Evaluate the use of pheromone-baited traps to sample adult male mullein bug (the more prevalent mirid in our trials to date), to predict the density of nymphs present the following spring (2nd year).
Mullein plant bug (MPB) nymphs were observed in numbers as high as four times the preliminary threshold estimate, but there was only slight damage, even in the check plots. For that reason, little information was to be had regarding objectives 1, 2, and 3. As for objective 4, comparisons in a number of apple blocks at the Experiment Station showed no relationship between adult MPB trap catches and nymph density the following spring. This may be due to the lack of information on which to rate varietal susceptibility or to the small block size. Comparisons of larger, commercial apple blocks did show a strong correlation between trap catches and nymph density, but the sample was small. Additional information on MPB phenology was gathered, indicating that tree growth stage is a better predictor of MPB egg hatch than is degree-day accumulation.