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

Abstract

[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 to 5×10 virus occlusion bodies (OBs) L, 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 1×10-1×10 OBs L, 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 OBs L 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 >60min of feeding.

[Conclusion] This information should prove useful in the registration of ChchSNPV-TF1 as a bioinsecticide in the Canary Islands and Europe.