Stage-specific insecticidal characteristics of a nucleopolyhedrovirus isolate from Chrysodeixis chalcites enhanced by optical brighteners
Chrysodeixis chalcites is a major noctuid pest of banana crops in the Canary Islands. The stage-specific susceptibility of this pest to C. chalcites single nucleopolyhedrovirus (ChchSNPV-TF1) was determined, as well as the effect of selected optical brighteners as enhancers of primary infection.
Susceptibility to ChchSNPV-TF1 occlusion bodies (OBs) decreased as larval stage increased; second instars (L2) were 10 000-fold more susceptible than sixth instars (L6). Virus speed of kill was 42 h faster in L2 than in L6. OB production increased in late instars; L6 larvae produced 23-fold more OBs than L4. Addition of 10 mg mL−1 Tinopal enhanced OB pathogenicity by 4.43- to 397-fold depending on instar, whereas 10 µL mL−1 Leucophor resulted in potentiation of OB pathogenicity from 1.46- to 143-fold. Mean time to death decreased by 14 to 26 h when larvae consumed OBs in mixtures with 10 mg mL−1 Tinopal, or 10 µL mL−1 Leucophor, although in these treatments OB yields were reduced by up to 8.5-fold (Tinopal) or up to 3.8-fold (Leucophor).
These results have clear applications for the use of ChchSNPV-TF1 as a biological insecticide in control programs against C. chalcites in the Canary Islands. © 2013 Society of Chemical Industry