Do Ready-Mix Insecticides Cause Lethal and Sublethal Effects on Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) Pupa?

Abstract

The use of selective insecticides aids farmers in maintaining pest populations below the economic threshold level. The integrated use of biological and chemical control is only possible if the effects of insecticides on natural enemies are studied. Although the IOBC/WPRS standards allow us to compare these studies worldwide, the methods used are sometimes inconsistent. This study determined the effects of ready-mix insecticides applied on pupae of Trichogramma pretiosum (Riley, 1879) (Hymenoptera: Trichogrammatidae) and compared the effects on emergence of two different methods of exposing T. pretiosum pupae to insecticides: immersed or sprayed using a Potter tower. Both methods gave the same results, indicating that they can be compared. Moreover, it is important to go beyond IOBC/WPRS classification and study the effects of pesticides on different biological parameters of natural enemies. This additional step may increase the likelihood of successful integration of biological and chemical control. Based on the emergence reduction, Chlorantraniliprole + lambda-cyhalothrin, abamectin + chlorantraniliprole, and alpha-cypermethrin + teflubenzuron were classified as innocuous (class 1). Cypermethrin + profenofos and cyproconazole + thiamethoxam were classified as slightly harmful (class 2). Methanol + methomyl and lufenuron + profenofos were classified as harmful (class 4). Abamectin + chlorantraniliprole, although classified as innocuous, reduced the parasitism, longevity, and flight capability of the adult parasitoids. None of these insecticides altered the emergence and sex ratio of the second generation.

Selectivity of insecticides with two active ingredients on the parasitoid >i<Trichogramma pretiosum>/i< (Hymenoptera: Trichogrammatidae)

“…Then, approximately 100 parasitized eggs were placed in each test unit . (Paiva et al, 2020) -modified based on .…”

Controle biológico de >i<Gymnandrosoma aurantianum>/i< Lima, 1927, o bicho-furão-dos-citros, com o parasitoide de ovos >i<Trichogramma atopovirilia>/i< Oatman & Platner, 1983

“…3.4.2. Avaliação dos efeitos letal e subletais em pupas de T. atopoviriliaPedaços de papel contendo 25 ovos de G. aurantianum foram submetidos ao parasitismo por 24 h, sendo então, 7 dias após, imersos nas soluções dos diferentes produtos e no tratamento controle, por 5 segundos(De Paiva et al 2020;Asrar et al 2022). Após a 2022).…”