Imidacloprid as a contact arrestant for larvae of the European chafer, Amphimallon majale

Abstract

Larvae of A. majale do not remotely detect imidacloprid in the soil; they neither evade contact, nor are repelled after contact. Imidacloprid thereby acts as a contact arrestant to disrupt grub movement. This finding might help to explain the synergistic effect of imidacloprid in combination with other biological agents for white grub control, and its effects on grub overwintering behavior.

Comparative toxicity of two neonicotinoid insecticides at environmentally relevant concentrations to telecoprid dung beetles

“…During the first 24 h of the 10-day soil bioassay, qualitative observations of beetles across the neonicotinoid treatments revealed a period of morbidity and intoxicated behaviors of rolling on their backs and twitching of legs. Similar sub-lethal effects from imidacloprid products were described by Zhu et al 71 , where exposed third-instar European chafer larvae, A. majale , were paralyzed or displayed sustained inactivity. Arrestant behavior increases the susceptibility to exogenous biotic and abiotic factors, as well as increases prolonged AI contact.…”

“…For example, Grewal et al 68 determined imidacloprid- and thiamethoxam-treated turfgrass disrupted the overwintering behavior and vertical migration of P. japonica third-instar larvae; more than 50% of the grubs collected from control plots were below 10 cm in the soil column, compared to 10% of the grubs collected from the neonicotinoid-treated plots. Zhu et al 71 described arrestant behavior A. majale , where in third-instar were not deterred by and could not remotely detect imidacloprid-treated soil. Macropores in soils created by root channels or subterranean invertebrates can facilitate the vertical movement of water in the soil profile and leaching of neonicotinoids 84 .…”

Lethal and behavioral effects of synthetic and organic insecticides on Spodoptera exigua and its predator Podisus maculiventris

“…The prolonged contact of S . exigua with the spinosad in the treated portion of the dish may indicate an arrestant effect of this compound, as reported for the European chafer, Amphimallon majale (Razoumowsky) (Coleoptera: Scarabaeidae) larvae with imidacloprid [ 60 ]. This neonicotinoid causes sublethal effects on natural enemies such as the predatory P .…”