Morphological and pathogenic variability of Colletotrichum gloeosporioides incitinganthracnose in betel vine (Piper betle L.)

Abstract

Asurvey conducted to assess betel vine anthracnose caused by colletotrichum sp in three southern districts ofKerala revealed that disease incidence varied from 20 to 80 per centand severity from 5.70 to 20.00 per cent. Five differentisolates (C1, C2, C3, C4 and C5) of Colletotrichum sp. obtained from the survey showed wide cultural and morphologicalvariability in PDA medium. The nature of mycelial growth was either fluffy or sparse and colony colour showed amultitude of variation from white, off white, orange to pinkish among the different isolates. The mycelia were hyaline,branched and septate. The mean septal width ranged from 2.65 μm - 3.45 μm and distance from 8.50 μm - 25.56 μm wererecorded among the C. gloeosporioides isolates. The conidia and appressorial dimensions varied from 9.6 - 12.2 μm x 3.7- 4.3 μm and 8.37 - 10.08 x 5.02 - 6.28 μm in length and breadth respectively. The isolates had a significant pathogenicvariability with respect to the symptom development, lesion size and rate of lesion development on artificial inoculation.Among the five isolates of C.gloeosporioides, C2 was the most virulent producing maximum lesion size (14.75 mm) within two days after inoculation when compared to the other isolates