In vitro Evaluation of Some Fungicides and Tea Extract Against Pestalotia sp. and Colletotrichum sp., The Causal Agents of Leaf Spot and Anthracnose of Azalea

The effect of five fungicides and tea extracts was tested against anthracnose disease and leaf spot of Azalea during summer (2015) at the laboratory in Rasht Branch, Islamic Azad University. Commercially formulated fungicides at 1000, 2000 and 3000 ppm concentrations and the regression of normalized growth rate were used to determine the EC50. The application of different fungicides on Pestalotia sp., Bavistin 50WP, Dithane M-45, Aliette, Benlate 50 WP and Topsin M 70 WP gave significant reduction in colony growth, i.e. 0.5, 0.5, 0.50, 3.38 and 2.56 mm, respectively as compared to control (88.00 mm) in 2000 ppm at recommended doses. The application of different fungicides on Colletotrichum sp. Resulted in significant reduction in colony growth. The fungicides were tested against Colletotrichum sp. at 1000, 2000 and 3000 ppm concentrations, and no growth was observed in Mancozeb, Thiophanate-methyl and Fosetyl aluminum at any concentrations. Three of the tested fungicides suppressed mycelial pathogen growth effectively. However, there were significant differences in the sensitivities exhibited by the examined pathogen isolates. Concentrations of extracts from fresh tea leaves used to control the disease agents could not prevent the growth of fungal colony.