ABSTRACT
The caterpillar Anticarsia gemmatalis (Lepidoptera: Noctuidae) is a prevalent pest in soybean plantations, managed using both natural and synthetic chemical products. However, the emergence of resistance in some populations emphasizes the need to explore alternative insecticides. Flupyradifurone, a neurotoxic insecticide, has not been previously used for controlling A. gemmatalis. This study evaluated the potential of flupyradifurone in the management of A. gemmatalis. Initially, the toxicity and anti-feeding effects, as well as histopathological and cytotoxic impacts, of flupyradifurone on A. gemmatalis were evaluated. Subsequently, the indirect effects of flupyradifurone on the midgut and fat body of the predator Podisus nigrispinus (Hemiptera: Pentatomidae) were verified. The results indicate the susceptibility of caterpillars to flupyradifurone, with an LC50 of 5.10 g L-1. Furthermore, the insecticide adversely affects survival, induces an anti-feeding response, and inflicts damage on the midgut of the caterpillars. However, flupyradifurone also leads to side effects in the predator P. nigrispinus through indirect intoxication of the caterpillars, including midgut and fat body damage. While flupyradifurone demonstrates toxicity to A. gemmatalis, suggesting its potential for the chemical control of this pest, the indirect negative effects on the predator indicate the need for its controlled use in integrated pest management programs with the insecticide and the predator.
ABSTRACT
The entomopathogen Bacillus thuringiensis (Bt) is widely used as one of the ingredients in pest control formulations, but researches conducted on its effect on non-target organisms are still in the nascent stage. This investigation aimed to uncover if Bt treated with Tenebrio molitor (Coleoptera: Tenebrionidae) larvae and pupae could affect the biological variables of Podisus nigrispinus (Hemiptera: Pentatomidae) and Palmistichus elaeisis (Hymenoptera: Eulophidae), all of which established natural enemies of leaf defoliator caterpillars in the eucalyptus culture. Larvae of T. molitor were fed on wheat bran containing different concentrations of B. thuringiensis (0.00; 0.25; 0.50; 1.00; 2.00 and 4.00 g Agree/kg bran). When the larvae attained size of about 2 cm, they were used as prey for P. nigrispinus (Bioassay I), and their pupae used as hosts for P. elaeisis (Bioassay II). Only the biological variables oviposition period and egg numbers by posture of the predator P. nigrispinus were altered. The biological variables of P. elaeisis were not altered, since it was possible to use these control methods within the integrated pest management.(AU)
O entomopatógeno Bacillus thuringiensis é amplamente empregado no controle de pragas, porém estudos de seu efeito sobre organismos não alvo ainda são incipientes. Com isso, objetivou-se neste trabalho avaliar se larvas de Tenebrio molitor (Coleoptera: Tenebrionidae), tratadas com Bacillus thuringiensis, podem afetar as variáveis biológicas de Podisus nigrispinus (Hemiptera: Pentatomidae) e Palmistichus elaeisis (Hymenoptera: Eulophidae), importantes inimigos naturais de lagartas desfolhadoras na cultura do eucalipto. Larvas de T. molitor foram alimentadas com farelo de trigo contendo diferentes concentrações de Bacillus thuringiensis (0,00; 0,25; 0,50; 1,00; 2,00 e 4,00 g de Agree®/kg farelo). Quando as larvas atingiram em média 2 cm de comprimento, foram usadas como presa para P. nigrispinus (bioensaio I) e as pupas como hospedeiro para P. elaeisis (bioensaio II). As variáveis biológicas período de oviposição e número de ovos por postura do predador P. nigrispinus foram alteradas. Já as variáveis biológicas de P. elaeisis não foram modificadas, sendo possível o uso conjunto desses métodos de controle no manejo integrado de pragas.(AU)
