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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/10572

Title: Hall and Roger. A. Downer (2006). The impact of spray application methodology on the development of resistance to Cypermethrin and spinosad by Fall Armyworm Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Pest management science 62(11) 141-149
Authors: Al-Sarar, A. S.
Issue Date: 29-Dec-2010
Abstract: The development of resistance to an insecticide under various type of application methods has yet to be reported in the literature. Colonies Five fall armyworm reared in the chamber for 10 generations before starting topical application bioassay. From each FAW colony, 200-500 3rd -4th –instar larvae were fed for 72 hours on corn plant sprayed with cypermethrin or spinosad at minimum application rate (20 g ha-1) using the small droplet size nozzle XR8001vs (VMD 163µm) the large droplet nozzle XR8008vs (VMD = 519.1µm). surviving larvae were transferred to untreated corn leaves to complete their life cycle. Next generation 3rd instar larvae of each colony were topically dosed with technical cypermethrin or spinosad at 1µl/larvae and mortality recorded 24 hours post treatment. The results indicated that cypermethrin demonstrated an insecticidal activity greater than spinosad and the cypermethrin LD50 lines moved to the right faster than spinosad indicating an increased tolerance of cypermethrin. Generally, larvae from all generations (F1-F7) under the XR8008vs treatments were less susceptible to cypermethrin and developed resistance faster and to higher levels than larvae from the XR8001vs treatments. The confidence limits (95%) of LD50 for all spinosad treatments indicated there was no significant difference from the LD50 value of the susceptible reference strain. The results are a first indicating that application technology/ insecticide reaction may affect the rapidity of resistance development in certain pest/ plant scenarios but field studies are needed to confirm this conclusion.
URI: http://hdl.handle.net/123456789/10572
Appears in Collections:College of Foods And Agricultural Science

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