Understanding the Etiology of Chilli Fruit Rot Disease in Tamil Nadu

Background: Fruit rot is an age old destructive disease of chilli caused by complex fungal pathogens resulting in severe yield losses both at pre and post-harvest stages. Hence, this study aims to investigate the occurrence of fruit rot disease in Tamil Nadu and to identify the fungal pathogens associated with fruit rot symptoms based on morpho-molecular characters. Methods: Roving survey was conducted in various districts of Tamil Nadu to determine the prevalence of fruit rot disease and to ascertain its causative agents. The pathogens were identified based on the conidial morphology, cultural characteristics and further confirmed by Polymerase chain reaction (PCR) using ITS 1 and ITS 4 primers. Result: Maximum disease severity was documented in Dharmapuri followed by Namakkal and lowest in Nagapattinam district. Ten isolates representing two genera viz., Colletotrichum and Fusarium were recovered from fruit rot infected chilli fruits and validated by pathogenicity test. Based on the morpho-cultural characters, 2 isolates were identified as Fusarium sp., with oval/ellipsoidal microconidia and straight/curved macroconidia, 6 isolates as Colletotrichum scovillei with fusiform conidia and 2 isolates as Colletotrichum truncatum with falcate conidia. The virulent isolates were further confirmed as C. scovillei based on PCR amplification of ITS region of genomic DNA.
