Submitted to: Insect and Plant Cold Hardiness Symposium
Publication Type: Abstract Only
Publication Acceptance Date: February 23, 2000
Publication Date: June 13, 2000
Citation: Neven, L.G., Ferguson, H.J. 2000. Use of transgenic viruses to impair cold hardiness in insect pests. Insect and Plant Cold Hardiness Symposium. Technical Abstract: Pest insects of deciduous tree fruits are well adapted to the extreme temperatures experienced in temperate regions. The major tree fruit lepidopterous pests in Pacific Northwest apple and pear orchards are codling moth (CM), Pandemis leafroller (PL), oblique-banded leafroller (OBLR) and Lacanobia fruitworm (LFW). The three tortricid pests, CM, PL, OBLR overwinter as cocooned larvae while the noctuid pests, LFW, overwinters as a pupa. All of these insects are freeze sensitive and avoid freezing by extensive supercooling. Control of overwintering populations by impairing cold hardiness is a possible strategy we are pursuing. Understanding the mechanisms by which these species overwinter is key in developing a control system using transgenic baculoviruses designed to thwart cold hardiness in fruit pests. Baculoviruses are not always immediately lethal to the host insect. Larvae may live up to two weeks with low level infections, while continuing to damage fruit and trees. When the insect is infected with the virus the supercooling point is elevated. The elevation of the supercooling point makes the insect more likely to freeze at temperatures normally experienced during a winter in the Pacific Northwest.