Imported Longhorned Weevil (Coleoptera: Curculionidae)

Paper: 85
Year: 2003
Authors: Hunt, T. E., L. G. Higley, and F. J. Haile
Title: Imported Longhorned Weevil (Coleoptera: Curculionidae)
Journal: Journal of Economic Entomology
Volume: 96
Summary: The imported longhorned weevil, Calomycterus setarius Roelofs, is an occasional pest
of soybean, Glycine max (L.), and can cause substantial defoliation of seedling soybean when the
weevil is present in large numbers. Because weevil populations can reach high levels, the potential
exists for signiÞcant seedling injury, so economic injury levels (EILs) are needed for imported
longhorned weevil on seedling soybean. Because the bean leaf beetle, Cerotoma trifurcata (Forster),
also is present on seedling soybean, injury by this insect should be included in EIL calculations. This
study was conducted to (1) determine daily soybean consumption rates of imported longhorned
weevil; (2) compare soybean injury responses between weevil injured and noninjured soybeans; and
(3) develop multiple species EILs for imported longhorned weevil and bean leaf beetle. Field and
laboratory studies were conducted in 1997 to determine weevil daily consumption rates. Field
experiments were conducted in 1998 to examine physiological responses of soybean to weevil injury.
Field and laboratory consumption rates were 0.16 and 0.21 cm2 per day, respectively. There were no
signiÞcant differences in physiological responses (i.e., photosynthetic rates, stomatal conductance,
and transpiration rates) between noninjured soybean leaßets (caged) and weevil-injured leaßets.
Multiple-species EILs were developed for imported longhorned weevil and bean leaf beetle on VC
through V3 soybean.