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Combined treatments of spinosad and chlorpyrifos‐methyl for management of resistant psocid pests (Psocoptera: Liposcelididae) of stored grain
Author(s) -
Nayak Manoj K,
Daglish Gregory J
Publication year - 2007
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.1313
Subject(s) - spinosad , chlorpyrifos , toxicology , biology , pesticide , psocoptera , chemistry , botany , agronomy
The combined efficacy of spinosad and chlorpyrifos‐methyl was determined against four storage psocid pests belonging to genus Liposcelis . This research was undertaken because of the increasing importance of these psocids in stored grain and the problem of finding grain protectants to control resistant strains. Firstly, mortality and reproduction were determined for adults exposed to wheat freshly treated with either spinosad (0.5 and 1 mg kg −1 ) or chlorpyrifos‐methyl (2.5, 5 and 10 mg kg −1 ) or combinations of spinosad and chlorpyrifos‐methyl at 30 °C and 70% RH. There were significant effects of application rate of spinosad and chlorpyrifos‐methyl, both individually and in combination, on adult mortality and progeny reduction of all four psocids. Liposcelis bostrychophila Badonnel and L. decolor (Pearman) responded similarly, with incomplete control of adults and progeny at both doses of spinosad but complete control in all chlorpyrifos‐methyl and combined treatments. In L. entomophila (Enderlein) and L. paeta Pearman, however, complete control of adults and progeny was only achieved in the combined treatments, with the exception of spinosad 0.5 mg kg −1 plus chlorpyrifos‐methyl 2.5 mg kg −1 against L. entomophila . Next, combinations of spinosad (0.5 and 1 mg kg −1 ) and chlorpyrifos‐methyl (2.5, 5 and 10 mg kg −1 ) in bioassays after 0, 1.5 and 3 months storage of treated wheat were evaluated. The best treatment was 1 mg kg −1 of spinosad plus 10 mg kg −1 of chlorpyrifos‐methyl, providing up to 3 months of protection against infestations of all four Liposcelis spp. on wheat. Copyright © The State of Queensland, Australia, Department of Primary Industries and Fisheries (2006). Published by John Wiley & Sons, Ltd. & Sons, Ltd.