The Efficacy of the New Fungicide Prochloraz against Lecanicillium fungicola (Preuss) Zare & Gams, the Agent of Dry Bubble Disease on Button Mushroom

Nowadays a special attention has been paid to cultivation, production and consumption of button mushrooms ( Agaricus bisporus L.) besides the other agricultural activities in the country. Dry rot or dry bubble disease with the causal agent Lecanicillium fungicola is one of the key diseases of button mushrooms. In the present study, the efficacy of different doses (0.3, 0.6, 0.9, 1.2 and 1.7 gr/m 2 ) of the new fungicide prochloraz (Accord ® WP 50%) was compared with the older brand of prochloraz (Sporgon ® WP 50%) (0.9 gr/m 2 ). This experiment was carried out in a completely randomized blocks design with eight treatments and four replicates in Iranian Research Institute of Plant Protection during 2012 and 2013. Substrates were inoculated with selected isolate of L. fungicola at a concentration of 6×10 5 spore/ml immediately after casing and fungicides treatments 7 days after that. When caps appeared, the weight and number of them and also disease incidence were evaluated as the efficiency indexes. Data analysis of weights and numbers of healthy caps and also disease incidence (%) obtained during the two years of the experiments, show that there is a significant difference between treatments ( P=1%). Comparison of the means of both the years by Duncan test (P=1%) show that, Accord WP50%, at a rate of 0.9 gr/m 2 , 7 days after casing and Sporgon WP 50% (0.9 gr/m 2 , 7 days after casing) produced the most crops considering average caps numbers and weights and they had the lowest percent of disease incidence. Therefore they showed comparatively better efficacy.