Premium
The effects of temperature, humidity and rainfall on captan decline on apple leaves and fruit in controlled environment conditions
Author(s) -
Xu XiangMing,
Murray Roy A,
Salazar Jose D,
Hyder Kieran
Publication year - 2008
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.1520
Subject(s) - captan , fungicide , pesticide , humidity , relative humidity , agronomy , environmental science , toxicology , biology , meteorology , geography
BACKGROUND: Captan is an important fungicide for controlling diseases in horticultural crops. Predicting its dissipation is important for estimating dietary risks and optimising pesticide application. Experiments were conducted to determine the relationship of captan loss on apple leaves with temperature, humidity and rainfall, and to investigate captan loss on fruit in dry conditions. RESULTS: There was large unit‐to‐unit variability in captan residues in spite of the controlled application. Temperature and humidity had negligible effects on captan loss. Captan loss is predominately due to washoff by rain, although a certain proportion of captan may bind to the plant surface tightly and hence may not be readily removed by rain. About 50% of captan can be washed off by as little as 1 mm of rain after an application, and the loss appeared not to relate to the amount of rain. Under dry conditions, daily loss of captan is estimated to be around 1% on both fruit and leaves, giving a half‐life of ca 70 days. CONCLUSIONS: Captan loss on leaf and fruit surfaces is primarily due to rain washoff. Copyright © 2008 Society of Chemical Industry