Short communication: Sublethal effects of insecticides used in strawberry on Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)

Daniel M Alano,Maria A C Zawadneak,Ida C Pimentel,Emily S Araujo,José M Mirás-Avalos

doi:10.5424/sjar/2021191-17235

Abstract

Aim of study: Assessment of toxicity and sublethal effects of registered insecticides currently used in strawberry cultivation in Brazil on Trichogramma pretiosum Riley adults.Area of study: The study was conducted under laboratory conditions in Paraná (Brazil).Material and methods: Previously non-parasitized Duponchelia fovealis Zeller (Lepidoptera: Cambridae) eggs were dipped into insecticide dilutions or control solution. Seven active ingredients were tested: thiamethoxam, abamectin, azadirachtin, spinetoram, chlorfenapyr, lambda-cyhalothrin and chlorpyriphos. Side-effects of pesticides were quantified by measuring mortality on T. pretiosum females in 24 h, longevity after exposure to the insecticides, parasitism and emergence rates, and offspring sex ratio. These traits were also measured on the second generation.Main results: According to IOBC criteria, thiamethoxam was classified as harmless; abamectin, chlorfenapyr and spinetoram as slightly toxic; azadirachtin and lambda-cyhalothrin as moderately toxic and chlorpyriphos as toxic. The emergence rate of T. pretiosum secondgeneration was not significantly affected by thiamethoxam, abamectin, azadirachtin, and chlorfenapyr. Sublethal effects caused by azadirachtin, abamectin and chlorfenapyr were verified in the secondgeneration.Research highlights: The information generated by this study is useful for designing future biological control strategies in integrated pest management programs against D. fovealis.

Highlights

The members of the Trichogrammatidae family rank among the most important biotic agents employed around the world (Gallego et al, 2019; Araujo et al, 2020; Schäfer & Herz, 2020)
The percentage of survival for T. pretiosum females of the F0 generation was significantly different between the control and abamectin, spinetoram, chlorpyriphos, chlorfenapyr and lambda-cyhalothrin treatments, 24 h after exposure to the insecticides (Fig. S1a [suppl])
The longevity of T. pretiosum females from the F0 generation decreased significantly for all active ingredients (AIs) (p< 0.001) when compared to the control (Table 1). These reductions differed among AIs, according to IOBC criteria, thiamethoxam, azadirachtin, lambda-cyhalothrin were classified as slightly toxic, whereas abamectin, spinetoram, chlorfenapyr and chlorpyriphos were classified as moderately toxic (Fig. 1)

Summary

Introduction

The members of the Trichogrammatidae family rank among the most important biotic agents employed around the world (Gallego et al, 2019; Araujo et al, 2020; Schäfer & Herz, 2020). The percentage of survival for T. pretiosum females of the F0 generation was significantly different between the control and abamectin, spinetoram, chlorpyriphos, chlorfenapyr and lambda-cyhalothrin treatments, 24 h after exposure to the insecticides (Fig. S1a [suppl]).

Results

Conclusion