Effect of Horticultural Oil on Oviposition Behaviour and Egg Survival in the Obliquebanded Leafroller (Lepidoptera: Tortricidae).

Wins-Purdy, A.H., Whitehouse, C., Judd, G.J.R., and Evenden, M.L. (2009). "Effect of Horticultural Oil on Oviposition Behaviour and Egg Survival in the Obliquebanded Leafroller (Lepidoptera: Tortricidae).", Canadian Entomologist, 141(1), pp. 86-94. doi : 10.4039/n08-042  Access to full text

Abstract

The effects of the horticultural oil Purespray Green on oviposition behaviour and egg development in the obliquebanded leafroller, Choristoneura rosaceana (Harris), were investigated through dual-choice and no-choice bioassays and topical applications of oil to developing eggs. A residual 2% (v/v) oil spray on wax-paper and apple-leaf substrates significantly reduced both the number of eggs laid and egg survival in no-choice assays, females laid significantly fewer eggs on oil-treated apple leaves than on control leaves, but laid equal numbers of eggs on the oil-treated wax paper controls. Topical application on oil caused significant dose-dependent mortality of both newly laid eggs and eggs just before hatch, and these two egg stages were equally susceptible to the oil. Topical application of 2% oil caused >99% egg mortality. Our data indicate that gravid female C. rosaceana can assess and reject oil-sprayed surfaces and that the oil can kill eggs through both contact toxicity and suffocation. These characteristics suggest that highly purified horticultural oils like Purespray Green could play a role in an integrated pest management for this important pest species.

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