Sulfoxaflor and Natural Pyrethrin with Piperonyl Butoxide Are Effective Alternatives to Neonicotinoids against Juveniles of Philaenus spumarius, the European Vector of Xylella fastidiosa

Abstract

The threat imposed by the bacterial pathogen Xylella fastidiosa to crops of utter importance to European agriculture such as olive, stone fruit and grapevine calls for immediate research against the meadow spittlebug, Philaenus spumarius (L.), the main European vector. Management tools should consider reducing juveniles of vector populations growing on weeds or cover crops during spring as nymphs have limited movement and do not contribute to disease spread. We examined a wide range of insecticides with different modes of action against P. spumarius nymphs in laboratory and semi-field glasshouse conditions. Pyrethroids (delthamethrin and λ-cyhalothrin) and natural pyrethrin (Pirecris®) + piperonyl butoxide (PBO) efficacy surpassed 86% after 24 h of exposure, without significant differences in the PBO amount tested. The inclusion of PBO caused a 3-fold increase in the mortality of P. spumarius nymphs compared to pyrethrin alone. Sulfoxaflor (Closer®) exhibited similar efficacy at 48 and 72 h but it was slow acting and mortality only reached 60% at 24 h. The LC90 was 34 ppm at 72 h. Pymetrozine, spirotetramat, azadirachtin and kaolin were not effective against nymphs (mortality <33%) although in azadirachtin-treated plants, mortality had a 3-fold increase from 24 to 72 h. Our results will help decision-making policy bodies to set up a sustainable integrated pest management of P. spumarius in areas where X. fastidiosa becomes a problem.