Green tea extracts as ultraviolet protectants for the beet armyworm, Spodoptera exigua, nucleopolyhedrovirus

The addition of a caffeinated green tea, Camellia sinensis L., filtrate (1%) to the nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hubner), provided almost complete protection following UVB irradiation (30 min) in laboratory tests. There were few differences in UV protection when extracts were prepared at 27 or at 90 degrees C. Moreover, few differences in UV protection were demonstrated following infusion times of 5, 15, 30, and 60 min at 90 degrees C. At a 1% concentration, decaffeinated and caffeinated green teas were equally effective as UV protectants. At lower concentrations (0.1, 0.01, and 0.001%) caffeinated green tea provided greater UV protection (UVB/UVB 30, 60 min). Virus/tea extracts (caffeinated), under field conditions at 1 and 5%, were ineffective as UV screens. At a 10% concentration, some UV protection was provided and UV protection further increased in a concentration-dependent manner.