In vitro efficacy of fungicides, bioagents and plant extracts against anthracnose of Bt-cotton caused by Colletotrichum gossypii

Abstract

Cotton production is being hampered by several diseases caused by pathogens; among them the anthracnose disease of cotton is becoming a serious impediment for cotton production. The anthracnose disease of cotton caused by Colletotrichum gossypii is very destructive, wide spread throughout the country and gaining importance from economic point of view. The present investigation was undertaken to evaluate the In vitro efficacy of fungicides, bioagents and plant extracts against Colletotrichum gossypii causal agent of Bt- cotton Anthracnose. The results revealed that among systemic fungicides viz., Propiconazole 25% EC, Difenoconazole 25% EC, and Tebuconazole 25.9% EC recorded complete mycelial growth inhibition with cent per-cent inhibition over control (00.00 mm and 100%) and were significantly superior over all the treatments at both concentrations 500 ppm and 1000 ppm. among the non-systemic fungicides, Propineb 70% WP at 2000 ppm recorded complete inhibition of the mycelial growth with cent percent inhibition over control (0.00 mm and 100%) while, at 2500 ppm Propineb 70% WP, Mancozeb 75% WP, and Zineb 75% WP recorded complete inhibition of the mycelial growth of Colletotrichum gossypii with cent per-cent inhibition over control (0.00 mm and 100%). Whereas, among the combi fungicides viz., Carbendazim 12% + Mancozeb 63%, Azoxystrobin 2.5% + Thiophanate Methyl 11.25% + Thiamethoxam 25% FS and Metalaxyl 8% + Mancozeb 64% WP were found most effective in inhibiting the mycelial growth of Colletotrichum gossypii with cent per-cent inhibition over control (0.00 mm and 100%). Trichoderma asperellum was found most effective against Colletotrichum gossypii with (70.55%) inhibition of mycelial growth followed by Trichoderma harzianum (55.37%). Among the plant extracts/botanicals highest mycelial growth inhibition was recorded with Allium sativum (88.70%) which was found significantly superior over all the treatments, followed by Curcuma longa with mycelial growth inhibition (79.25%).