EPIDEMIOLOGY AND MANAGEMENT OF COLLETOTRICHUM GLOEOSPORIOIDES CAUSING LEAF SPOT OF STRAWBERRY (Fragaria x ananassa Duch.) IN KERALA

Abstract

A fungal leaf spot caused by Colletotrichum gloeosporioides was found as a major problem in three strawberry growing tracts of Kerala viz., Malappuram, Idukki and Wayanad. Wayanad recorded highest Per Disease Index (PDI) and severity of 52.90 and 22.80 in December-January followed by 52.40 and 23.40 in March-April in Malappuram. Disease severity was negatively correlated with humidity (-0.868) and rainfall (-0.919) in Wayanad and positive correlation of 0.501 and 0.541 in Malappuram. Three isolates were obtained and brought into culture. In vitro management when carried out with nine fungicides, Saaf, Antracol, Bavisitin and Curzate M8 recorded 100 per cent inhibition, 70.77 to 100 per cent in case of Score, 77.77 to 100 in case of Fytolan and Bordeaux mixture. Akomin 40 recorded least inhibition ranging from 11.11 to 43.88 per cent. Biocontrol agents Trichoderma asperellum and Pseudomonas fluorescens recorded 100 and 66-70 per cent control. A pot culture experiment was conducted with C. gloeosporioides isolate from Wayanad using strawberry variety Winter dawn. T. asperellum followed by carbendazim 12% + mancozeb 63% recorded 88.07 and 86.48 per cent control which can be followed for efficient management of the disease under field conditions. Thus, T. asperellum and fungicide carbendazim 12% + mancozeb 63% is effective in reducing the leaf spot under in vivo conditions.