Brazilian Journal of Microbiology
Print version ISSN 1517-8382
KNAAK, Neiva and FIUZA, Lidia Mariana. Histopathology of Anticarsia gemmatalis Hübner (Lepidoptera; Noctuidae) treated with Nucleopolyhedrovirus and Bacillus thuringiensis serovar kurstaki. Braz. J. Microbiol. [online]. 2005, vol.36, n.2, pp. 196-200. ISSN 1517-8382. http://dx.doi.org/10.1590/S1517-83822005000200017.
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.
Keywords : virus; bacteria; biological control; Lepidoptera.