Fotoestabilidad y actividad insecticida de dos formulaciones de granulovirus sobre larvas de Tecia solanivora

the biological control laboratory of corpoica developed two formulations based on a native isolate of the phthorimea operculella granulovirus isolated from tecia solanivora larvae, for the control of these moths in the field. these formulations include a uv protector from the group of optical brighteners. to determine the effect of the brightener, viral suspensions adjusted to five concentrations from 102 up to 106 ci/ml were prepared in brightener solutions at 0.1% and 0.5% and a bioassay was performed to determine the viral lc50. afterwards the two formulations, an emulsifiable concentrate and a dispersible granule, were applied on potato tubers that were exposed to ultraviolet radiation during two, four, six, eight, and 10 hours and a bioassay was performed to determine viral inactivation level by evaluating insect mortality. higher viral activity was observed when brightener concentration was increased, obtaining a lc50 of 1.6 x 106 ci/ml for pure virus, 3.0 x 105 ci/ ml for the virus with the photoprotector at 0.1% and 3.0 x 104 ci/ ml for the virus with the photoprotector at 0.5%, results that allow us to suggest the optical brightener presents a synergistic effect with the virus. both formulations efficiently protected the virus from the effect of uv radiation, obtaining corrected mortalities of 60% after 10 hours of exposure with the emulsifiable concentrate, 46.6% with the dispersible granule and 23.3% with the pure virus.