Effect of synthetic insecticides on the larvae of Coccinella septempunctata from Greek populations

Abstract

Coccinella septempunctata L. is one of the most abundant ladybird species in Greece, preying on several aphid species and other arthropods, of which many are pests of cultivated plants. These pests are usually controlled with chemical insecticides. During this process, however, beneficials are also exposed to pesticides. The development of Integrated Pest Management (IPM) programs against aphids requires the evaluation of the effects of insecticides on beneficial insects. We evaluated the LD 50 of imidacloprid, acetamiprid, bifenthrin and deltamethrin on first, second, third and fourth instar larvae of C. septempunctata by topical application. Moreover, we studied their sublethal effects (LD 10 ) on the development, weight and prey consumption of fourth instar larvae. The topical application bioassays showed that deltamethrin and bifenthrin were highly toxic to all larval instars, whereas imidacloprid and acetamiprid were less toxic to fourth instar larvae. The LD 10 dose significantly affected, developmental time, adult weight and daily predation. These results show the importance of assessing potential effect of insecticides on C. septempunctata for developing effective IPM programs of aphids in Greece.

Imidacloprid Movement into Fungal Conidia Is Lethal to Mycophagous Beetles

“…This conclusion is supported by previous observations that soil-applied imidacloprid is readily translocated into various tissues of C. pepo plants [17] and that the lethal effects of imidacloprid consumption on three different coccinellid species have been observed at 6.03 µg/g [18]. In general, imidacloprid is considered very toxic to coccinellid larvae, with lethal residues at concentrations as low as 2.6 µg/g [19] and lethal contact doses as low as 1.7 µg/g [20]. The levels of imidacloprid detected in the fungal conidia in our study exceeded all of these limits, even several weeks after the initial application of the insecticide material.…”

Bioaccumulation and Toxicity of Organic Chemicals in Terrestrial Invertebrates

“…These authors raised the concern that such complex behavioral changes in invasive ants might occur with other beneficial ant species upon exposure to neonicotinoids. Low levels of imidacloprid affected ladybugs by reducing their consumption of aphids, ultimately reducing adult body weight and inducing slower development, underlining the relevance of looking into effects on predatory species [120]. This agrees with Bredeson et al [121] who reported altered quality of Rhopalosiphum padi aphids for the predatory species C. maculata upon exposure to thiamethoxam.…”

Toxicity, Sublethal and Low Dose Effects of Imidacloprid and Deltamethrin on the Aphidophagous Predator Ceratomegilla undecimnotata (Coleoptera: Coccinellidae)

“…Imidacloprid has been found to reduce fecundity in coccinellids such as H. variegata and Nephaspis oculata [14,32] and affected predators' functional responses in Serangium japonicum and Harmonia axyridis (Colleoptera: Coccinellidae) [33,34]. On the other hand, only limited data are available on the impact of deltamethrin on Coccinellid predators [35].…”