• Droska, Jon S.
  University of Maine Graduate School
  

A field experiment was conducted in white pine (Pinus strobus L. ) plantations in central Maine in 1980 and 1981 to determine the effects of bark temperature, leader diameter, and shade on adult white pine weevil Pissodes strobi (Peck) behavior in the fall. Released (marked) weevils apparently left densely shaded habitats containing host trees with small diameter leaders. Weevils were more tolerant of dense hard wood shade if host trees possessed large diameter leaders (>1 cm). Bark temperatures of white pine leaders after the 1st of September remained within the temperature range (10-27 C) preferred by adult weevils regardless of treatment. A laboratory experiment revealed that spring and fall populations of adult weevils are positively phototactic to ultra violet light. These several factors influence the behavior of weevils in the fall resulting in reduced losses in shaded stands.