Communications Project

Document Type:Master's Thesis
Name:Katherine L. Knowles
Title:Impact of Low-Spray Mating Disruption Programs on Aphidophagous Insect Populations in Virginia Apple Orchards
Degree:Master of Science
Committee Chair: Dr. Douglas G. Pfeiffer
Committee Members:Dr. Jeffrey R. Bloomquist
Dr. Joella C. Killian
Dr. Scott M. Salom
Keywords:pheromone, apple, mating disruption, aphid, predator
Date of defense:May 23, 1997
Availability:Release the entire work for Virginia Tech access only.
After one year release worldwide only with written permission of the student and the advisory committee chair.


The populations of aphidophagous insects in low-spray and conventional programs were surveyed in Virginia apple orchards. Two sampling methods were utilized;aphid colony collection and beating tray collection. The low-spray blocks employed the use of mating disruption for control of the key direct pests, codling moth, Cydia pomonella (Linnaeus), and leafrollers. The abundance and diversity of aphid predators in low-spray mating disruption programs and conventionally controlled apple orchards was compared. Both sampling methods suggested that aphid predators were more plentiful in the mating disruption blocks. Several mating disruption blocks were found to accumulate significantly more predator-days and diversity than the matched control blocks. The reduction of insecticide input into the low-spray blocks may have allowed higher populations of aphidophagous insects to occur. Aphid populations in mating disruption blocks sometimes declined faster and had less resurgence than those in the conventionally controlled blocks. The tufted apple bud moth (TABM), Platynota idaeusalis (Walker), populations in four apple orchards in Winchester, Virginia, were compared for resistance to azinphosmethyl. These orchards were suspected by the growers to have resistant populations of TABM. Pheromone traps with insecticide incorporated into the adhesive were used to collect and test the moths. The results were not analyzed due to the low number of moths collected and high variability in mortality.

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