Bioefficacy and Phytotoxicity of Profenofos 50EC against Tea Red Spider Mite, Oligonychus coffeae (Nietner)

An experiment was conducted in the Experimental Garden for Plantation Crops, Assam Agricultural University, Jorhat during Kharif, 2013 and 2014 to evaluate the efficacy and phytotoxic effect of profenofos 50 EC, a new molecule of chemical pesticide against tea red spider mite, Oligonychus coffeae Nietner in comparison to the market samples of profenofos 50 EC. All the treatments were found to be significantly superior over control after 1st spraying. Profenofos 50 EC @ 750, 1000 and 1000 (market sample) g a. i. /ha proved to be most effective treatment that gave 100 per cent reduction of mite population after one day of spraying. Reduction of mite population due to new molecule of profenofos 50 EC @ 500 g a. i. /ha and profenofos 50 EC @ 500 g a. i. /ha (market sample) were 83.30 per cent and 80.83 per cent, respectively after one day of spraying. Profenofos 50 EC @ 250 g a. i. /ha was least effective and caused only 68.83 per cent reduction of mite population at the same duration. Similar trend of results were also noticed after 3 and 5 days of treatment. Profenofos 50 EC @ 1000 g a. i. /ha and profenofos 50 EC @ 1000 g a. i. /ha (market sample) proved to be the most effective having 70.46 per cent and 69.93 per cent reduction of mite eggs, respectively after one day of first spraying and were at par followed by profenofos 50 EC @ 750 g a. i. /ha which resulted 64.40 per cent reduction of eggs. Profenofos 50 EC @ 500 g a. i. /ha (market sample) resulted 63.06 per cent reduction of eggs. The least effective treatments over eggs were profenofos 50 EC @ 500 and 250 g a. i. /ha that resulted 61.16 per cent and 52.10 per cent egg reduction, respectively. Observation on phytotoxicity revealed that all the doses of profenofos 50 EC did not produce any symptoms of phytotoxicity in tea crop after 1, 3, 5, 7 and 10 days of spraying.