Submitted to: Entomological Society of America Annual Meeting
Publication Type: Other
Publication Acceptance Date: 11/6/2006
Publication Date: 11/6/2006
Citation: Jackson, D.M., Bohac, J. 2006. Resistance of Sweetpotato Genotypes to Spotted and Banded Cucumber Beetles. Entomological Society of America Annual Meeting, Dec 10-13, 2006, Indianapolis, IN (poster uploaded to ESA internet page http://esa.confex.com/esa/2006/techprogram.htm).
Technical Abstract: Bioassay techniques were developed for evaluating the resistance of sweetpotato germplasm to larvae and adults of the banded and spotted cucumber beetles. For the adult bioassay, individual beetles were placed on pieces of sweetpotato peel (periderm and cortex with stele removed) that was embedded periderm-side up in plaster in a Petri dish. Feeding and longevity of insects on 30 sweetpotato genotypes were evaluated in two experiments using this bioassay procedure. Adult longevity ranged from 7-11 days for starved individuals to 211 days for beetles fed a dry artificial diet. Longevity of beetles fed sweetpotato peels ranged from 12 days for the most resistant genotype to 123 days for SC1149-19, a susceptible control cultivar. For the larval bioassay, individual second instars were placed on plugs of sweetpotato periderm, cortex, or stele of four sweetpotato genotypes in microcentrifuge tubes. Diabrotica larvae grew larger when they were fed stele than when they were fed the peels of any sweetpotato genotype. Larval growth was not different among genotypes for any of the stele treatments. However, larval growth on the peel of the resistant genotypes (Regal and W-375) was significantly lower than for any of the other treatments. Larval survival was highest on the sprouted wheat control and the stele from the resistant genotypes.