Premium
Quantification of imidacloprid toxicity to avocado thrips, Scirtothrips perseae Nakahara (Thysanoptera: Thripidae), using a combined bioassay and ELISA approach
Author(s) -
Byrne Frank J,
Toscano Nick C,
Urena Anthony A,
Morse Joseph G
Publication year - 2005
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.1052
Subject(s) - imidacloprid , thripidae , biology , thrips , horticulture , bioassay , pest analysis , toxicity , toxicology , botany , pesticide , agronomy , chemistry , ecology , organic chemistry
A competitive ELISA (enzyme‐linked immunosorbent assay) technique was evaluated for quantifying titres of imidacloprid in homogenates of leaf discs sampled from avocado plants treated with systemic applications of imidacloprid 240 g litre −1 SC (Admire ® ). Matrix effects were evident with undiluted leaf tissue homogenates, but these were effectively eliminated by dilution of homogenates in water. In a field trial conducted in a commercial nursery, there was an excellent correlation between imidacloprid residues within leaves and avocado thrips ( Scirtothrips perseae Nakahara) mortality. However, with subsequent sampling over a 2‐month period, the relationship between mortality and apparent imidacloprid concentration became less robust, suggesting that the material was being degraded within the plant to non‐toxic metabolites. Nevertheless, assessments of thrips mortality on leaves that had been recently treated with imidacloprid established a lower threshold of activity for imidacloprid residues of 6 ng cm −2 leaf. Limitations on the use of ELISA to quantify the impact of systemic insecticides on pest populations are discussed. Copyright © 2005 Society of Chemical Industry