Potential ofAspongopus viduatusF. (Heteroptera: Pentatomidae) as a Biocontrol Agent for Squirting Cucumber,Ecballium elaterium(L.) A. Rich. (Cucurbitaceae)

Squirting cucumber,Ecballium elaterium,is a common weed in the Mediterranean Basin. It often becomes an agricultural pest and may also serve as a reservoir for viruses that infect cucurbitaceous crops. We found squirting cucumber plants near Rehovot, Israel, infested with a large number ofAspongopus viduatusbugs, and the infested plants dried out and died within a few days. In this study, we evaluated the potential ofA. viduatusas an inundative biocontrol agent for squirting cucumber by examining whether it is safe to crop plants, whether it can provide effective control within a short time, and how easy it is to rear it in large numbers. In no-choice tests, the bug was unable to become established on any of 21 different crop plants, except watermelon. When given a choice between watermelon and squirting cucumber, 80% of the bugs preferred the latter, regardless of their previous host plant or rearing conditions. There was a direct relationship between bug load and weed morbidity. Twenty adult bugs killed a squirting cucumber plant within 1 week, and the plants did not recover after the bugs had been removed. WhenA. viduatuswas reared in the laboratory at 24 ± 2°C on squirting cucumber, it took 5–6 weeks to develop from egg to adult. Each pair of adult bugs gave rise to about 470 adult progeny over a period of 5 months. Thus, prospects for mass rearing ofA. viduatusand effective control of squirting cucumber by augmentative releases appear to be good. However, the risk from this bug to watermelon must be determined under field conditions before it can be used safely as an augmentative biocontrol agent.