Imported Longhorned Weevil (Coleoptera: Curculionidae) Injury to Soybean: Physiological Response and Injury Guild-Level Economic Injury Levels

• Published in: Journal of economic entomology 2003-08, Vol.96 (4), p.1168-1173
• Main Authors: Hunt, Thomas E., Higley, Leon G., Haile, Fikru J.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Calomycterus setarius; Cerotoma trifurcata; Coleoptera - growth & development; Control; crop damage; Crops, Agricultural - economics; Curculionidae; defoliation; economic threshold; FIELD AND FORAGE CROPS; Fundamental and applied biological sciences. Psychology; Generalities; Glycine max; Glycine max - growth & development; insect pests; leaf development; leaf expansion; maturity stage; multiple species economic injury level; photosynthesis; Phytopathology. Animal pests. Plant and forest protection; phytophagous insects; Plant Diseases - economics; Plant Leaves; plant response; Population Density; Protozoa. Invertebrates; Seedlings - growth & development; soybean; soybeans; stomatal conductance; transpiration
• ISSN: 0022-0493; 1938-291X
• DOI: 10.1603/0022-0493-96.4.1168

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 significant 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 significant differences in physiological responses (i.e., photosynthetic rates, stomatal conductance, and transpiration rates) between noninjured soybean leaflets (caged) and weevil-injured leaflets. Multiple-species EILs were developed for imported longhorned weevil and bean leaf beetle on VC through V3 soybean.