A preliminary study on the toxicity of natural pyrethrins against Aphidius colemani Viereck (Hymenoptera: Braconidae), a polyphagous parasitoid of aphids

Abstract

This study represents a preliminary investigation on the toxicity of pure pyrethrins directly used against Aphidius colemani Viereck (Hymenoptera: Braconidae), parasitoid of various harmful aphids such as Aphis gossypii Glover, Myzus persicae (Sulzer) (Homoptera: Aphidiidae) and others. As little is known about the collateral effects of botanical insecticides on A. colemani, this study set out to investigate the insecticidal activity of pyrethrins, which were used for the first time against the adults of this parasitoid. Two commercial products were tested in the experiments: product A (pyrethrins 18.5g/l) and product B (pyrethrins 0.047g/l + rapeseed oil 8.25g/l) (5.5μl/ml dose), which are commonly used against pests of cultivated and ornamental plants. We evaluated the mortality of adult parasitoids at 24h, 48h, 72h and 96h after exposure to the treatment, under laboratory conditions. The results highlighted that both products showed adulticidal activity as early as 24 hours after exposure to the treatment, differing significantly from the control.