Open AccessInsecticide Enhancement with Feeding Stimulants in Corn for Western Corn Rootworm Larvae (Coleoptera: Chrysomelidae)
Author(s) -
E. J. Bernklau,
L. B. Bjostad
Publication year - 2005
Publication title -
journal of economic entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 101
eISSN - 1938-291X
pISSN - 0022-0493
DOI - 10.1603/0022-0493-98.4.1150
Subject(s) - western corn rootworm , thiamethoxam , biology , larva , bioassay , genetically modified maize , agronomy , distilled water , zea mays , pesticide , imidacloprid , botany , genetically modified crops , chemistry , ecology , transgene , biochemistry , chromatography , gene
Amounts of the insecticide thiamethoxam required for 50% mortality of western corn rootworm larvae, Diabrotica virgifera virgifera LeConte, were reduced 100-fold when extracts of germinating corn, Zea mays L., were used to entice neonate larvae to feed on it. In behavioral bioassays, neonate rootworm larvae fed vigorously on filter paper disks treated with liquid pressed from corn roots. Moreover, disks treated with an acetone extract of corn (dried and rewetted with water) also elicited strong feeding from larvae. Larvae wandered away from filter paper disks treated with distilled water without feeding. Dilutions of thiamethoxam were tested in the bioassay alone or with corn extract and the efficacy of this insecticide was improved by the addition of the corn extract. For solutions containing 10 ppm thiamethoxam, 95% larval mortality occurred after 30 min of exposure when corn extract was present, but only 38% mortality occurred when the same concentration of insecticide alone (no feeding stimulants) was tested. Larval mortality after 24 h was significantly higher for corn extract-treated disks with 0.01, 0.1, 1, or 10 ppm insecticide than for the same concentrations without corn extract. Thiamethoxam did not deter larval feeding on corn extract, even at the highest concentration of thiamethoxam tested.