Dissipation and Harvest Time Residue Analysis of Azoxystrobin in Chilli Srinivasan V.M.*, Krishnamoorthy A.S. Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu *Email: vmagri@rediffmail.com
Online published on 2 January, 2017. Abstract The fungicide azoxystrobin is a strobilurin group of fungicide showing broad spectrum of activity against wide range of plant pathogens. In the present study azoxystrobin was sprayed at different concentration viz., 250 ml ha−1 (62.5 g a.i ha−1), 500 ml ha−1 (125 g a.i ha−1), 750 ml ha−1 (187.5 g a.i ha−1) and 1000 ml ha−1 (250 g a.i ha−1) on chilli against fruit rot and powdery mildew diseases. In each treatment, 500 g of chilli fruit samples and soil samples were collected at 0, 5, 10 and 15 d after last spraying to determine the dissipation rate of azoxystrobin. In addition, 500 g of soil samples were also collected from the field trials at the time of harvest for residue analysis. GCMS analysis of azoxystrobin standard showed the retention time of 11.65 min in all the concentrations. Chilli fruits and soil samples collected from the control plots were artificially applied with azoxystrobin standard at 0.1, 0.3 and 0.5 ppm for the estimation of recovery percentage. The mean per cent recovery from chilli fruit was 99.90, 98.50 and 99.00 per cent and from field soil was 97.66, 98.50 and 98.34 per cent at the same concentrations. The harvest time residue of azoxystrobin on chilli fruits and soil of respective fields were analyzed and found that azoxystrobin was below detectable level (BDL) in all the samples (Fruit and soil) collected at the time of harvest. The observations on dissipation of azoxystrobin on chilli fruit showed that, azoxystrobin when applied at the rate of 125g a.i ha−1 left the initial deposit of 0.816 μg/g on 0th d and the initial deposit dissipated to 0.230 μgg−1 on 5th d. On 7th d it was0.056 μgg−1andreached below detectablelevel (BDL) after seventh DAS. In the case of azoxystrobin applied at the rate 250 g a.i ha−1 left the initial deposit of 1.603μgg−1on 0thdand the deposit dissipated to 0.780 μg g1 on 5th d. On 7th d it was 0.163μgg−1. There was no residue recorded after 7th DAS in both concentrations. The estimated half life of azoxystrobin in chilli fruit samples sprayed at the rate of 500 ml ha−1was1.70 d whereas it was 2.17 d when azoxystrobin sprayed at the rate of 1000 ml ha−1. Top Keywords Azoxystrobin, Chilli fruit rot, Powdery mildew, Residue, Dissipation. Top |