Development time and predation rate of Podisus maculiventris (Hemiptera: Pentatomidae) feeding on Microtheca ochroloma (Coleoptera: Chrysomelidae).

摘要

Microtheca ochroloma Stal is a beetle native to South America and was introduced to the United States in 1945. Since then, M. ochroloma has become a serious pest in crucifer crops because of the lack of natural enemies. The objective of this study was to measure the predation rate and development time of the commercially available predator Podisus maculiventris (Say) feeding on M. ochroloma at four constant temperatures in the laboratory as a first step to evaluating the predator's capability as a biological control agent of the pest. Nymphal development of P. maculiventris increased from 23 d at 25 degrees C to 99 d at 15 degrees C. There was no development of first instar or egg hatch at 10 degrees C. Number of fourth-instar M. ochroloma killed during nymphal development varied significantly from 65 at 15 degrees C to 53 at 20 degrees C because of length of the nymphal period. A mean total of 741 eggs of M. ochroloma were consumed during nymphal development at 25 degrees C. Adult P. maculiventris preyed on nine and 12 times more fourth-instar M. ochroloma during 10 d at 20 degrees and 25 degrees C, respectively, than at 15 degrees C. We conclude that P. maculiventris can develop successfully on a diet of eggs or fourth-instar M. ochroloma, but its predation and development rates will be significantly curtailed during the cool months from November to March when M. ochroloma is a key pest of organically grown crucifers in Florida.