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PERSISTENCE AND LEACHING BEHAVIOUR OF SPIROMESIFEN IN SOIL

KrishiKosh

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Title PERSISTENCE AND LEACHING BEHAVIOUR OF SPIROMESIFEN IN SOIL
 
Creator JAMKHOKAI MATE
 
Contributor Irani Mukherjee
 
Subject ---
 
Description T-8492
Spiromesifen, (Oberon) is a novel non-systemic insecticide belonging to the new chemical class of
tetronic acid derivatives discovered at Bayer Crop Science during the 1990s. It was registered in 2006 for crops
like chilli, tomato and okra for protection especially against whiteflies (Bemisia spp. and Trialeurodes spp.) and
mites. . It shows excellent ovicidal activity against mites wherein egg hatch in whiteflies is markedly reduced. It is
a foliar applied insecticide. There is no report available on persistence and mobility behavior of spiromesifen in
soil under Indian condition. In view of the above, a study entitled “Persistence and leaching behaviour of
spiromesifen in soil” was carried out under laboratory conditions. Analytical methodologies for analysis of
residues of spiromesifen from soil and water were standardized. Partitioning with dichloromethane for aqueous
samples and dipping and shaking with aqueous acetone followed by column clean up with neutral alumina for soil
samples were found suitable. Spiromesifen residues were analyzed by HPLC fitted with UV detector.
Persistence of spiromesifen was studied in soil collected from IARI campus; at two concentrations, 1.0
and 10 μg g-1, under three different moisture regimes viz. air-dry, field capacity and submerged. It was found that
the dissipation of the compound in soil varies with the soil moisture regimes, fortification levels and light
conditions. Trend in dissipation was submerged (t 1/2 14.3-16.7 days) > field capacity ( t1/2 18.7-20 days) > dry ( t1/2
21.9-22.9 days). Slightly faster dissipation was observed at 1.0 μg g-1 level as compared to 10 μg g-1 level.
Persistence experiments of spiromesifen were also conducted under sterilized dry and submerged conditions at 10
μg g-1 concentration level, the half life values were, sterilized dry 35.8 days and sterilized submerged 17.7 days.
Spiromesifen residues persisted in water beyond 120 day with a half-life ranging from 5.7-12.5 days. Dissipation
from water was faster at pH 9.2 (t1/2 5.7 days), followed by pH 4 (t1/2 9.7 days) and 7.0 (t1/2 12.5 days).
Application of 2.5% compost to soil enhanced degradation of spiromesifen under field capacity moisture regime (
t1/2 14.3 days).
Effect of light on degradation of spiromesifen was studied as thin film on petri plates and soil thin film
under field capacity condition at 10 μg g-1 by exposure to sunlight , UV-light and dark light. Residues dissipated
faster under UV-light (t1/2 3-4 days), in comparison to sunlight (t1/2 5.2-8.1 days) and dark light (t1/2 11.5-13.6
days). Leaching experiments were carried out in packed soil columns. Effect of analytical grade and its
formulation on leaching behavior of spiromesifen was studied. Reduced leaching was observed in case of
formulation as compared to analytical grade material. Leaching with 400 mL water equivalent to 1156 mm
rainfall, 68.08 and 77.5 % residues remained in top 0-10 cm soil layer in case of analytical grade and formulation
of spiromesifen, respectively. Effect of various components like FYM, vermicompost and nano clay on mobility of
spiromesifen was also studied. In all the cases no residues were observed in the leachate. The total recovery in 0-
10 cm soil depth with FYM, vermicompost and nano clay were 84.10, 86.10 and 97.7 %, respectively, indicating
high adsorption by nano clay followed by vermicompost and FYM. The results showed that the nano clay adsorbs
most of the compound when compared with FYM and vermicompost . Leaching studies conducted with, enol
spiromesifen, indicated it to be more mobile than the parent insecticide, spiromesifen. The enol metabolite
constituted 17.3 % in the leachate.
 
Date 2016-11-28T09:55:24Z
2016-11-28T09:55:24Z
2011
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/87772
 
Format application/pdf
 
Publisher IARI, DIVISION OF AGRICULTURAL CHEMICALS