USE OF OPTICAL BRIGHTENERS AS RADIATION PROTECTANTS FOR GYPSY-MOTH (LEPIDOPTERA, LYMANTRIIDAE) NUCLEAR POLYHEDROSIS-VIRUS

Twenty-three optical brighteners were tested as radiation protectants for the gypsy moth nuclear polyhedrosis virus (NPV). Three brighteners were ineffective (i.e., <10% original activity remained after ultraviolet [UV] irradiation), and 17 provided good protection (i.e., >70% original activity remained). Eight of the latter 17 brighteners (Intrawite CF, Leucophor BS, Leucophor BSB, Phorwite AR, Phorwite BRU, Phorwite BKL, Phorwite CL, and Tinopal LPW) provided complete protection (i.e., 100% original activity remaining) at a 1% concentration. At lower concentrations, Phorwite AR and Tinopal LPW were superior UV protectants. Mortality rates were also affected by several brighteners (Intrawite CF, Phorwite AR, Leucophor BS, Leucophor BSB, Tinopal LPW), and NPV-exposed insects died more quickly than those exposed to standard NPV + H2O.