ABSTRACT

Intensification and expansion of arecanut plantations in non-traditional areas is facing greater challenges of pest and diseases, among which anthracnose disease caused by Colletotrichum spp. is of greater concern. During survey highest disease severity was observed in Hiriyur taluk of Chitradurga district (53.33%) and a least disease severity was recorded in Shiggaon taluk (26.03%) of Haveri district. Disease progress was favoured by congenial epidemiological conditions like rainfall, high temperature and high relative humidity.
On Potato Dextrose Agar (PDA) medium, Colletotrichum spp. produced whitish orange colony. Conidia were found to be single celled, hyaline, cylindrical, containing one to two oil globules. All the 15 isolates of Colletotrichum spp. collected from different arecanut gardens showed cultural variability on PDA medium. Shravanagere isolate showed excellent sporulation. Big sized conidia were observed in Malebennur isolate. Sequencing of ApMat gene region for ten isolates has revealed the presence of C. cordylinicola in six isolates and C. siamense species in four isolates.
In vitro effective and economically viable contact fungicide, copper oxychloride 50% WP (0.3%), combiproduct fungicide (hexaconazole 5% + captan 70%) 75% WP (0.2%), a bioagent, Trichoderma harzianum (MH027645.1) IOF strain (1%) and a botanical azadirachtin 0.15 % (1%) were used in the evaluation spray schedule for management of anthracnose of arecanut. Spray schedule involving (hexaconazole 5% + captan 70%) 75% WP (0.2%) followed by (hexaconazole 5% + captan 70%) 75% WP (0.2%) and (hexaconazole 5% + captan 70%) 75% WP (0.2%) followed by Trichoderma harzianum (MH027645.1) IOF strain (1%) sprayed at an interval of 15 days starting from the appearance of disease has reduced the anthracnose severity (21.95% and 22.67% respectively) compared to unsprayed control (33.33%).