Baseline toxicity of several pesticides to Hyaliodes vitripennis (Say) (Hemiptera: Miridae)

Abstract

Hyaliodes vitripennis (Say) is a univoltine indigenous predacious mirid. It has been reported in several orchards where IPM programmes are used. It is a generalist, and feeds on phytophagous mites in addition to other arthropods. In Quebec, a foliar application of imidacloprid, deltamethrin or lambda-cyhalothrin is used at least once per season to manage arthropod pests such as leafhoppers and leaf-eating caterpillars. Meanwhile, several applications of metiram, flusilazole, myclobutanil and mancozeb are made to control apple scab [Venturia inaequalis (Cooke) Winter]. In laboratory trials, comparison of lethal concentrations of the three insecticides against H vitripennis nymphs and adults showed no significant difference. However, when lethal concentrations were compared between two growth stages for each insecticide, a significant difference was noted between adults and nymphs treated with lambda-cyhalothrin, adults being more susceptible than nymphs. No such difference could be detected for imidacloprid or deltamethrin. When LC50 values were compared with the manufacturer's label rates, deltamethrin and imidacloprid were toxic to the nymphs and adults, and lambda-cyhalothrin was slightly toxic to the nymphs and moderately toxic to the adults. Among the fungicides evaluated in the laboratory, myclobutanil showed moderate toxicity to adults at the manufacturer's label rate. The remaining fungicides had no toxic effects to adults or nymphs, even at four times the manufacturer's label rate.

The effect of indoxacarb and five other insecticides on Phytoseiulus persimilis (Acari: Phytoseiidae), Amblyseius fallacis (Acari: Phytoseiidae) and nymphs of Orius insidiosus (Hemiptera: Anthocoridae)

“…When the results of this study were compared with the earlier study, it appeared that the adults were more susceptible than the nymphs. A similar observation had been reported with lambda‐cyhalothrin and Hyaliodes vitipennis (Say) (Hemiptera: Miridae) 18. The toxicity data for P. persimilis with indoxacarb showed no significant difference from the control, and the value of the t ratio of the slope was less than 1.96 (5% significance point for the t distribution with infinite degrees of freedom), which meant that the probit response curve was not a linear function of the concentration and that increased concentrations did not increase the mortality (Table 2).…”

The intrinsic toxicity of several neonicotinoids to Lygus lineolaris and Hyaliodes vitripennis, a phytophagous and a predacious mirid

“…When we compared lethal concentration ratios between adults and nymphs (Table 7), a significant difference in toxicity was evident only with thiamethoxam, and the adults were significantly more susceptible than the nymphs (Table 7). A similar observation had been reported earlier with λ‐cyhalothrin and H vitripennis 22…”

“…The estimated LC 50 values of these neonicotinoids towards H vitripennis are so low when compared with the recommended rates to manage arthropod pests in orchards that these compounds would be classified as extremely toxic under laboratory conditions. Wherever H vitripennis is a key predator of phytophagous mites in orchards, this pronounced toxicity virtually rules out the usefulness of these neonicotinoids, as well as imidacloprid,22 against orchard pests from late June to the end of August. During that period, H vitripennis adults and nymphs are highly mobile, preying on mites in the tree canopy and even with spray coverage less than 100% in an orchard, these predacious mirids would eventually make contact with sprayed leaves and be poisoned.…”

Effects of a Chenopodium‐based botanical insecticide/acaricide on Orius insidiosus (Hemiptera: Anthocoridae) and Aphidius colemani (Hymenoptera: Braconidae)

“…The LC 50 values suggest that O insidiosus adults (LC 50 11.28 g AI liter −1 ) are more susceptible than second‐instar nymphs (LC 50 29.15 g AI liter −1 ) to UDA‐245. A similar observation with Hyaliodes vitripennis (Say) had been reported by Bostanian et al 25…”