Toxicity of chlorantraniliprole in extrafloral nectar of cotton plant from seeds treated for Harmonia axyridis (Coleoptera: Coccinellidae) and Chrysoperla externa (Neuroptera: Chrysopidae)

Abstract

The use of systemic insecticides in seed treatment is considered safer for non-target organisms compared to other forms of application. For this reason, there is concern about possible effects that contaminated extrafloral nectar may cause on beneficial organisms. (1) Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) and (2) Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) were studied in order to evaluate the effect of chlorantraniliprole on the development, when larvae and adults of these predators were exposed to cotton plants grown from seeds treated with this insecticide, as well as to gather information from the main studies carried out with chlorantraniliprole seed treatment for eight natural enemies in three cultures. Chlorantraniliprole did not cause a lethal effect on H. axyridis, but transgenerational negative effects were observed. When larvae were exposed to the contaminated extrafloral nectar there was a reduction in larval and pupal development time, males weight and insect survival of the next generation to that exposed. Ladybugs from adults who came in contact with contaminated extrafloral nectar also had reduced pupal development time, egg viability and survival. The predator C. externa did not present negative transgenerational effects, and only when larvae were exposed to the product, the pupae formed had a minor development period. The other biological characteristics observed were not negatively influenced by the insecticide. Larvae of H. axyridis are attracted to untreated cotton plants compared to cotton seedlings treated with chlorantraniliprole; however, C. externa adults were attracted to cotton plants from treated or untreated seeds. For the predators Lysiphlebus testaceipes (Cresson) (Hymenoptera, Braconidae, Aphidiinae), Coleomegilla maculata (Coleoptera: Coccinelidae), Orius insidiosus (Say) (Hemiptera: Anthocoridae) and C. externa, the insecticide was classified as slightly harmful; However, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), H. axyridis, Hippodamia convergens (Guérin-méneville) (Coleoptera: Coccinellidae) and Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) chlorantraniliprole were harmless according to IOBC toxicity classification.