Persistence of insecticides used in peach orchards to larvae and adults of the predator Chrysoperla externa (Neuroptera: Chrysopidae)

Abstract

This work aimed to evaluate the persistence (duration of harmful activity) of five insecticides used for pest control in peach orchards, on larvae and adults of the predator Chrysoperla externa. The insecticides were sprayed on cv. Bordô vine plants using the maximum dosage recommended for peach orchards. Weekly, at 3, 10, 17, 24 and 31 days after spraying, larvae and adults of the predator were exposed to treated leaves in order to assess the residual effect of insecticides on mortality and possible effects on reproduction. Given the toxicity observed along the weekly bioassays, the insecticides were classified into persistence categories established by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). High persistence was obtained for the organophosphorus insecticides (% of active ingredient) phosmet (0.100) and malathion (0.200), and both were considered persistent (> 30 days of harmful activity) to larvae and adults of C. externa. Similarly, the benzoylurea insecticide lufenuron (0.005), which acts exclusively on immature stages of insects, was persistent to larvae. Differences concerning the persistence for both development stages evaluated were observed for the pyrethroid insecticide deltamethrin (0.001), that was persistent to larvae but moderately persistent (16 – 30 days of harmful activity) to adults; and for the organophosphate fenthion (0.050) which was considered moderately persistent to larvae and short-lived (< 5 days of harmful activity) to adults of C. externa.

Residual toxicity of four insecticides on larvae and adults of the predator Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae)

“…The persistence of insecticides is not always evaluated in studies involving the selectivity of pesticides, but this information helps determine the impact of insecticides on non-target organisms and to estimate the survival of the population of natural enemies after exposure to chemical control (CASTILHOS et al, 2019;PASINI et al, 2020). Castilhos et al (2019) also reported the importance of persistence tests in orchards, such as peach orchards, which are highly dependent on chemical control to control primary pests. Maintaining predators such as C. externa in orchards is thus important, and persistence tests would assist in decision making regarding whether to flood an area with this predator, as this should take place after the persistent interval.…”

“…The bioassays were conducted following the IOBC methodologies proposed by Hassan and Abdelgader (2001), Castilhos et al (2019) and Pasini et al (2020). The plants were sprayed using a pressurized CO 2 sprayer with a flat jet nozzle (Teejet XR110015EVS).…”

“…Termos de Indexação: Crisopídeo, Persistência, Controle químico, Controle biológico, Frutíferas de clima temperado. (Hemiptera: Aphididae), both in orchards in Brazil (CASTILHOS et al, 2019) and worldwide (RAMESHGAR et al, 2019).…”

“…In Brazil, C. externa has been used to test the selectivity and persistence of several insecticides in peach crops (CASTILHOS et al, 2019) and in wheat (PASINI et al, 2020). Therefore, the aim of this study was to evaluate the residual action (duration of harmful activity) of four insecticides used to control G. molesta and A. fraterculus, in the larval and adult stages of the predator C. externa, using the methodology proposed by the IOBC.…”

Inseticidas em pomares de citros e sua seletividade sobre o parasitoide >i<Trichogramma atopovirilia>/i< (Hymenoptera: Trichogrammatidae)

“…O impacto que um inseticida causa a uma população de organismos benéficos pode ser mensurado por sua persistência no ambiente, bem como sua toxicidade residual (Castilhos et al, 2019). Um dos primeiros itens a ser verificado ao iniciar a implantação de uma estratégia de manejo de pragas com o uso de controle biológico é conhecer a toxicidade dos inseticidas sobre as pragas e seus inimigos naturais (Morales et al, 2019).…”