Date of Award:

5-1-1989

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Biology (Entomology)

Committee Chair(s)

Vince Jones

Committee

Vince Jones

Committee

Don Davis

Committee

Chuck Hawkins

Committee

Sherm Thomson

Abstract

Populations of apple maggot were collected from an abandoned tart cherry orchard and from a native black hawthorn patch. Developmental times for egg, larvae and pupae were determined at 15, 20, 25 and 30 °C and then were compared to determine if differences existed between populations. For the egg stage, there were no significant differences between the populations at any temperature. For the larval stage, there was a significant difference in developmental times between populations only at 15 °C. For pupae undergoing diapause, significant differences were found at 15, 20 and 25 °C. Based on developmental times, pupal developmental thresholds were calculated to be 6.5 °C (1154 DD) and 6.5 °C (1121 DD) for apple maggots infesting tart cherry and black hawthorn, respectively. For pupae not undergoing diapause, there was no adult emergence at 15 °C and significant differences in developmental times were found at 20 and 25 °C. The effects of cold period duration and simulated rain on adult apple maggot emergence were investigated under laboratory conditions. Pupae were exposed to cold periods ranging from 9 to 191 days. There was no adult fly emergence from pupae exposed to 23 or less days of cold. The degree day (6.5 °C threshold) requirements for first fly and 50% emergence increased for pupae exposed to cold periods ranging from 37 to 65 days; however, flies exposed to longer cold periods (79 - 191 days) required fewer heat units for emergence. The effect of simulated rain (2 cm) on adult fly emergence was tested at various degree day accumulations (677 - 1065) during pupal development. Pupae exposed to rain at any of the degree day accumulations tested required significantly fewer heat units for first fly and 50% emergence, compared to pupae not exposed to rain.

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