Development of <i><scp>C</scp>litoria ternatea</i> as a biopesticide for cotton pest management: assessment of product effect on <i><scp>H</scp>elicoverpa</i> spp. and their natural enemies

Abstract

Abstract The A ustralian cotton industry is now dominated by transgenic (Bt) varieties, which provide a strong platform for integrated pest management ( IPM ) of H elicoverpa spp. ( L epidoptera: N octuidae). New IPM ‐compatible tools are required to manage the development of resistance in H elicoverpa spp. and the control of other sucking pests. A 10‐year study commenced in 2001 to identify short‐range, non‐volatile compounds on organ surfaces of plants that deter feeding or oviposition, or are toxic and do not support development of H elicoverpa spp. on cotton plants. The results of the initial study identified C litoria ternatea L . ( F abaceae) as non‐preferred for H elicoverpa spp. oviposition and larval feeding. The study found that C . ternatea fractionalized extract mixture (fractions 2, 3, 4, and 6) caused oviposition and feeding deterrence as well as direct toxicity to H elicoverpa spp. This study has developed an oil‐based semiochemical product from C . ternatea identified in the initial study into a potential commercial product. The application of 1–2% (vol/vol) of the oil‐based formulation of the C . ternatea mixture against H elicoverpa spp. on commercial transgenic and conventional cotton crops resulted in H elicoverpa spp. oviposition and larval feeding deterrence, as well as caused direct mortality to larvae. No negative effect on beneficial insects was observed. In conclusion, the ability of the oil‐based C . ternatea mixture to control H elicoverpa spp. infestations, while conserving beneficial insect populations, suggests its potential for use in supplementing IPM programs to reduce the use of synthetic insecticides on transgenic and conventional cotton crops.