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Activity of chlorantraniliprole and thiamethoxam seed treatments on life stages of the rice water weevil as affected by the distribution of insecticides in rice plants
Author(s) -
Lanka Srinivas K,
Stout Michael J,
Beuzelin Julien M,
Ottea James A
Publication year - 2014
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.3570
Subject(s) - thiamethoxam , weevil , biology , agronomy , oryza sativa , pesticide , toxicology , imidacloprid , biochemistry , gene
Abstract BACKGROUND The systemic insecticides chlorantraniliprole ( CAP ) and thiamethoxam ( TMX ), applied to rice as seed treatments, may affect multiple life stages of the rice water weevil, Lissorhoptrus oryzophilus . Effects of CAP and TMX on adult survival, egg‐laying and first‐ and late‐instar survivals were determined by infesting plants treated as seeds with different rates of insecticides. The biological activity was related to insecticidal concentrations in leaves, shoots and roots . RESULTS CAP did not affect adult survival but decreased egg numbers and reduced the survival of the first and late instars. The greatest reduction in weevil population occurred in late instars feeding on roots. In contrast, TMX reduced adult survival and egg and larval numbers. The high biological activity of CAP on root‐feeding stages was consistent with the accumulation of CAP in roots, whereas in TMX ‐treated plants the high activity on adults correlated with high concentrations of TMX in leaves and stems . CONCLUSIONS The differential activity of insecticides on adults suggests poor inherent potency of CAP as an adulticide and/or its limited systemicity in foliage. The distribution of insecticide in specific plant parts can be attributed to the different physicochemical properties of CAP and TMX . The field implications of this research on management of L. oryzophilus are discussed. © 2013 Society of Chemical Industry