Experimental use of Epinotia aporema granulovirus (EpapGV), in Argentina.

BIEDMA, M.E; SALVADOR, R; FERRELLI, ML; ROMANOWSKI, V; MERLO, V.H.; QUINTANA, G; ROMANOWSKI, V; SCIOCCO-CAP, A

Wuhan

Congreso; IX International Colloquium on Invertebrate Pathology and Microbial Control (ICIPMC), XXXIX Annual Meeting of the SIP and VIII International Conference on Bacillus thuringiensis (ICBt); 2006

Epinotia aporema (Lep. Tortricidae) is a major pest of legume crops in South America. An indigenous granulovirus (EpapGV), was characterized and the results indicated its potential as a candidate to be used as a bioinsecticide for the management of E. aporema. Towards this end, a formulation of this baculovirus was developed and tested under laboratory conditions, and the registration process was initiated in order to evaluate its performance under field conditions. In addition, to increase the prospective utilization of EpapGV and to design optimized strategies to be introduced in the management of lepidopteran pest in the main Argentinean soybean area, we tested its interaction with Anticarsia gemmatalis nucleopolyhedrovirus (AgMNPV). The ability of granuloviruses to enhance NPVs infection is well documented, and important from a practical point of view. Bioassays were conducted on third instars of A. gemmatalis, using the synchronous per oral technique. The LD50 value of AgMNPV was estimated at 168 OBs/larvae. Based on this result, three doses of AgMNPV were selected (300, 150 and 50 OBs/larva) and tested alone, in mixture with EpapGV (6000 OBs/larva), and also in combination with 0.1% boric acid. Mortality was recorded daily, and viral identity in dead larvae was determined by PCR reaction using specific primers. An apparently synergistic action was observed in the viral mixtures, in which a decrease of the LT50 was verified (i.e., 6.3 days with a dose of 300 AgMNPV OBs/larva vs. 5.4 days with 300 AgMNPV/6000 EpapGV OBs/larva). Similar results were obtained with the combination of AgMNPV and 0,1% boric acid. However, the addition of this component to the mixed viral suspension did not caused any additional effect. These results suggest that EpapGV increases the virulence of AgMNPV, and the use of formulations that include both viruses, might be a valuable tool for pest management in areas with temperate climates, where the homonymous pests are frequently present simultaneously, E. aporema has high incidence on legume crops, and AgMNPV has a slow speed of action.