Differential impacts of six insecticides on a mealybug and its coccinellid predator.
Ecotoxicol Environ Saf
; 147: 963-971, 2018 Jan.
Article
em En
| MEDLINE
| ID: mdl-29029382
ABSTRACT
Broad-spectrum insecticides may disrupt biological control and cause pest resurgence due to their negative impacts on natural enemies. The preservation of sustainable pest control in agroecosystems requires parallel assessments of insecticide toxicity to target pests and their key natural enemies. In the present study, the leaf dipping method was used to evaluate the relative toxicity of six insecticides to the striped mealybug, Ferrisia dasylirii (Cockerell) (Hemiptera Pseudococcidae) and its predator, Tenuisvalvae notata (Mulsant) (Coleoptera Coccinellidae). Three neurotoxic insecticides, lambda-cyhalothrin, methidathion and thiamethoxam, caused complete mortality of both pest and predator when applied at their highest field rates. In contrast, lufenuron, pymetrozine and pyriproxyfen caused moderate mortality of third-instar mealybug nymphs, and exhibited low or no toxicity to either larvae or adults of the lady beetle. At field rates, lufenuron and pymetrozine had negligible effects on prey consumption, development or reproduction of T. notata, but adults failed to emerge from pupae when fourth instar larvae were exposed to pyriproxyfen. In addition, pyriproxyfen caused temporary sterility; T. notata females laid non-viable eggs for three days after exposure, but recovered egg fertility thereafter. Our results indicate that the three neurotoxic insecticides can potentially control F. dasylirii, but are hazardous to its natural predator. In contrast, lufenuron and pymetrozine appear compatible with T. notata, although they appear less effective against the mealybug. Although the acute toxicity of pyriproxyfen to T. notata was low, some pupal mortality and reduced egg fertility suggest that this material could impede the predator's numerical response to mealybug populations.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Besouros
/
Controle Biológico de Vetores
/
Poluentes Ambientais
/
Hemípteros
/
Inseticidas
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
País como assunto:
America do sul
/
Brasil
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article