Histopathology of Anticarsia gemmatalis Hübner (Lepidoptera; Noctuidae) treated with Nucleopolyhedrovirus and Bacillus thuringiensis serovar kurstaki

Abstract

The Anticarsia gemmatalis is responsible for the use of chemical insecticides in the soybean culture, causing a significant increase in the costs of farming and a great unbalance in the ecosystem. The use of microbial agents, like Bacillus thuringiensis serovar kurstaki (Btk) and Anticarsia gemmatalis nucleopolyhedrovirus (AgNPV), they are an alternative to chemical control of the pest insects. In the interaction analysis of the entomopathogenic bacteria and virus it is considered important the in vitro action mode of these microbiology control agents. Therefore, the present study aims the histopathological analysis of the A. gemmatalis larvae digestive system after the interaction in vivo of the entomopathogenic Btk and AgNPV, represented the Dipel and Baculovirus anticarsia formulations, respectively. The evaluations were realized in larvae of 2nd instar, in which the mortality was evaluated daily, and a histopathology was done with collected larvae in time of 1, 3, 6, 12 and 24 hours after the treatments application. The results of the in vivo assays reveal that the treatment using the association of AgNPV-Btk (98.68% of mortality) was more efficient than using AgNPV isolatedly (81.28% of mortality), but the Btk when used isolatedly had a mortality of 100%. The treatments showed significant (P<0.05) differences between AgNPV and Btk, AgNPV and AgNPV/Btk. The histopathological analysis of the AgNPV and Btk in A. gemmatalis larvae suggests that the Dipel and Baculovirus anticarsia products were more efficient when they were used simultaneously, because the action of AgNPV was intensified when used in association with Btk, causing changes in the larvae midgut after 6 hours of treatments. When the entomopathogens were used isolating the gut cells alterations were observed only 12 hours after the treatments.

The effect of sub-lethal doses of Azadirachta indica (Meliaceae) oil on the midgut of Spodoptera frugiperda (Lepidoptera, Noctuidae)

“…These effects have also been described to other insect species as Ephestia küehniella (Pyralidae) (Smith et al 1969); Apis mellifera (Apidae) (Jimenez & Gilliam 1990); Hyalophora cecropia (Saturniidae) (Anderson & Harvey 1996), and Anticarsia gemmatalis (Noctuidae) (Levy et al 2004;Knaak & Fiuza 2005). These authors suggested that the phenomenon of cytoplasm loss is probably correlated to cell degeneration in epithelial renewal.…”

Impact of Bt cotton on the immune system and histology of the midgut of the fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

“…The Oriental leafworm, Spodoptera litura (Fabricius), ingesting Bt endotoxin respond with slight elongation of the epithelial cells (Pandey et al, 2009). Similar results in the abnormal growth of epithelial cells were observed with Baculovirus anticarsia (AgNPV) and commercial Bt toxin Dipel® for Anticarsia gemmatalis (Hübner) (Knaak & Fiuza, 2005). Furthermore, Rausell et al (2000) found vacuolization of cytoplasm and disarrangement of epithelial cells of Lymantria monacha (L.) treated with Bacillus thuringiensis Berlinier toxins CrylAa, CrylAb, CrylAc and CryB.…”

Histopathology and the lethal effect of Cry proteins and strains of Bacillus thuringiensis Berliner in Spodoptera frugiperda J.E. Smith Caterpillars (Lepidoptera, Noctuidae)

“…Similar changes were observed in intoxications with Cry1Ac and Cry1D in S. frugiperda (Aranda et al, 1996), thus confirming the data reported in this study for the Cry1Ac protein synthesised by the B. thuringiensis kurstaki HD-73 isolate. Knaak and Fiuza (2005) tested the nuclear polyhedrosis virus of Anticarsia gemmatalis Hübner, 1818, (VPNAg) and B. thuringiensis kurstaki HD-1 (Dipel ® ) in 2 nd instar caterpillars of A. gemmatalis (Lepidoptera, Noctuidae), and observed that when both entomopathogens are utilised simultaneously they are more efficient, because they caused alterations in the intestinal cells after 6 HAT while when used separately they produced the alteration only after 12 HATs. This data is similar to that obtained in the present study because the treatment with B. thuringiensis kurstaki HD-73 also demonstrated alterations in the microvilosities after 12 HATs.…”