Testing the efficacy of conventional and organic insecticides against an outbreak bush-cricket colonizing vineyards

The endemic species Barbitistes vicetinus (Orthoptera, Tettigoniidae) is a flightless bush-cricket that is recognized as a pest in certain hilly areas of northeastern Italy. Under favorable conditions, its population can increase to outbreak levels, causing severe damage to broadleaf trees and crops, particularly vineyards and olive groves. Current population management methods rely on insecticide sprays; however, environmentally compatible chemical control options are still to be evaluated. In this study, we compared the effects of six active ingredients, representative of both conventional and organic insecticides, through field and laboratory trials; we also assessed the impact of different dosages for selected compounds. Vine shoots were sleeved and nymph and adult bush-crickets were caged before the application. Among the active ingredients tested, spinosad and deltamethrin were effective in killing bush-crickets under all experimental conditions. Doses as low as one-fourth of the standard deltamethrin application rate resulted in adult mortality levels comparable to those observed with the full dose. Pyrethrins exhibited moderate insecticidal activity, with enhanced effectiveness at double the standard dose against both nymphs and adults. High adult mortality was observed seven days after treatment with the fungal entomopathogens Metarhizium anisopliae and Metarhizium acridum. These data provide valid support for updating the guidelines aimed at controlling B. vicetinus for growers, landscape managers, and homeowners and can help guide future authorization processes for the tested active ingredients.