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A Contribution of ICAR National Fellow Project

दीमक से बचाव के लिए देशी तकनीकPopularising the Termitexpert web-portal

Miscellaneous - Research


Pesticide Residue Analysis (PRA)
[Publication: Mahapatro et al. 2013, Indian J. Ent. 75(4): 336-337]
Wheat
We proved the bio-efficacy of imidacloprid as soil amendments in winter wheat with no residue recorded. However, chlorpyriphos residues were obtained in research plots with chemi-irrigation system. This practice was rampant previous years (before 2010-11), which we discouraged outrighty.
Maize:
A large-scale field trial (1 acre/treatment) for termiticides in maize crop is carried out with spray delivery targeted to rhizosphere and stem portion, one month prior to harvesting i.e., in the silking - grain filling stage. Residue analyses were done in the Agricultural Chemistry Division. No residues was found in the maize grains (imidacloprid, ND<0.01; chlorpyriphos, ND<0.0002; & fipronil, ND<0.001 mg/kg grains, below detection levels). Thus recommended insecticides (fipronil & methyl parathion @25 kg/ha, imidacloprid 0.5% spray to root zone) against termites are proved safe from residue point of view.
 
Residue analysis is done in the Agricultural Chemistry Division following standard protocol. Maize samples were processed by extraction in a Soxhlet extractor with organic solvent for 6-hrs. The extract was concentrated and subjected to liquid-liquid partitioning with acetonitrile hexane and then into dichloromethane. The samples were analyzed by HPLC-UV for imidacloprid, and by GLC-ECD for chlorpyriphos and fipronil. The results are given. No residue was found in the maize grain samples (imidacloprid, ND<0.01; chlorpyriphos, ND<0.0002; & fipronil, ND<0.001 mg/kg grains, below detection levels). This specific-spray strategy can easily be incorporated directly into maize IPM strategies involving less environmentally harmful generic insecticides for protecting the crop, with a comparatively cleaner and healthy, natural environment for sustainable agriculture.
 
Residue analyses results of the termiticidal trial in maize (kharif, 2011-12)
 
Sample
Dose
Residues (mg/kg) in maize grains
Remarks
Imidacloprid (Confidor® 17.8%SL)
1
Single dose (X = 1L/ha)
BDL
 
ND < 0.01 mg/kg
2
Double dose (2X)
BDL
3
Control
ND
Chlorpyriphos (Dursban® 20%EC)
1
Single dose (X= 2L/ha)
BDL
 
ND < 0.0002 mg/kg
2
Double dose (2X)
BDL
3
Control
ND
Fipronil (Regent®, 0.3% G)
1
Single dose (X = 25kg/ha)
BDL
ND < 0.001 mg/kg
2
Control
ND
BDL – Below detectable level, ND – Not detected
Wheat, barley, gram & lentil: 
[Publication: Mahapatro 2015: Lead-paper; 11th National Symposium:  Dynamics of Crop Protection in Agri-horticultural Ecosystems facing Climate Change. 23-25 April 2015, MPUAT, Udaipur] Awarded in this Symposium.
Termiticides used in the rabi crops (2012-13), were analyzed for residues in the harvested commodities (wheat, barley, gram & lentil). Residues were found below detectable level, implying the safety aspects of termiticides recommended (imidacloprid 17.6%SL, chlorpyriphos 20%EC, and fipronil 0.3%G).
Residue analyses were done for crop commodities after harvest in the Pesticide Referral Laboratory (credit - Division of Agricultural Chemicals. AOAC protocol was followed; analysis was carried out on Perkin elmer GLC-ECD Shimadzu HPLC fitted with PDA detector for imidacloprid.
 
Commodity (grains)
Pesticides tested
Fipronil
Chlorpyriphos
Imidacloprid
Methyl parathion
 
BDL= Below detectable level
BDL (mg/kg)
<0.001
<0.001
<0.05
<0.01
Barley
BDL
BDL
 
--
Gram
BDL
BDL
 
 
Lentil
BDL
BDL
 
 
Wheat
BDL
BDL
--
BDL
 
Results of pesticide risk analysis advocated that the termite management module followed was full proof and safe. Thus it can be advised for the farmers in rain fed agriculture (for crops viz. barley, gram, lentil and wheat). Using multiple termiticides viz. synthetics, botanicals and various biopesticides already proved useful for termite control in Delhi region (Mahapatro et al., 2013) in case of wheat and a few insecticides were found effective for seed treatment in the same crop (Shukla, 2010). Application of fipronil reported better in management of termites in wheat (Henderson and Forschler, 1996). In present study the efficacy of termite management module also was supported by these findings.
 
 
Chlorpyriphos treatment in irrigation leaves soil residues:
a crude but common farmers' practice must be discouraged

Last Updated: 04-01-2020

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