Factors Influencing Effectiveness of Artificial Oviposition Devices for Apple Maggot1

Abstract

Paraffin-petrolatum domes or Parafilmed® wire hemispheres developed as oviposition devices for the apple maggot, Rhagoletis pomonella (Walsh), were more effective (l) when used in cages shaded from direct light than when in unshaded cages; (2) when positioned on the cage floor and upright than when 13 cm above the floor or inverted; and (3) when baited with pre-ripe, crisp chunks of apple than when baited with fresh juice from such apples, apple cider, apple essence, or unbaited, Adults in unshaded cages appeared more excited and died earlier than adults in shaded cages. Paraffin-petrolatum domes were more effective (1) when formed with a smooth, rather than an irregular outer surface; (2) when colored with the largest amount of blue dye tested (short of that affecting the consistency of the paraffin-petrolatum mixture); and (3) when formed with the largest mesh size of cheesecloth tested. Wire hemispheres surfaced with 5 layers of Parafilm were more effective than those with 1 or 10 layers. When the most favorable levels of each of these factors were incorporated into a single experiment, a mean of 217.1 eggs per female (yielding 181.5 larvae) was obtained using paraffin-petrolatum domes and 133.9 eggs per female (yielding 117.8 larvae) using Para filmed wire hemispheres. Oviposition was at its peak when the adults were 4-6 weeks old; some continued to lay viable eggs even when 20 weeks old. Under the most favorable conditions, females lived an average of 69 days and males 60 days. An inadvertent increase in the relative humidity in some cages from the normal level of circa 51% to that of 85% or more resulted in earlier death of many adults. When moisture began to condense on the outer surface of the oviposition devices, females did not oviposit.