Efficacy of an alphabaculovirus‐based biological insecticide for control of Chrysodeixis chalcites (Lepidoptera: Noctuidae) on tomato and banana crops

BACKGROUND Chrysodeixis chalcites (Esper) is a major pest of tomato in Mediterranean countries and attacks banana in the Canary Islands (Spain). The efficacy of Chrysodeixis chalcites single nucleopolyhedrovirus ( ChchSNPV‐TF1 ) was evaluated in plant growth chambers and greenhouse trials performed on tomato and banana plants respectively. Treatments were applied using a compressed air sprayer. RESULTS Mean (± SE ) lethal infection varied from 77 ± 10% to 94 ± 3% in second‐instar larvae fed for 2 days on tomato plants treated with 2 × 10 6 to 5 × 10 7 virus occlusion bodies ( OBs ) L −1 , increasing to ∼100% infection after 7 days. Mortality of larvae collected from banana at different intervals post‐application varied from 54 ± 10% to 96 ± 4% in treatments involving 1 × 10 8 –1 × 10 9 OBs L −1 , whereas indoxacarb (Steward 30% WG ) and Bacillus thuringiensis var. kurstaki (Biobit 16% WP ) treatments produced between 22 ± 6% and 32 ± 5% pest mortality. All treatments significantly reduced plant defoliation compared with untreated controls. Application of 1 × 10 9 OBs L −1 was 3–4‐fold more effective than chemical or B. thuringiensis treatments. Larvae acquired lethal infection more rapidly when feeding on tomato than banana plants, but this difference disappeared following >60 min of feeding. CONCLUSION This information should prove useful in the registration of ChchSNPV‐TF1 as a bioinsecticide in the Canary Islands and Europe. © 2014 Society of Chemical Industry