Study on the etiology and ecology of fungal pollu in pepper

Abstract

Laboratory and filed experiments of the “study on the etiology of fungal pollu” was conducted at Pepper Research Station, attached to the College of Horticulture, vellanikkara from 1978-1979. The pathogen associated with the disease was found to be Colletotrichum gloeosporioides. The initial symptom of the disease observed on leaves tender shoots and berries was chlorotic specks. Only physiologically active leaves were infected. The well developed leaf spot under dry condition were circular to irregularly circular in shape. Under humid moisture conditions, the leaf spot enlarged quickly and the hononecrotic area was ashy white in colour. Pedicel infection caused the shedding of the spike. Infected tender shoots dried. Rachis infection was noticed rarely. The infected berries became dried, shrivelled, dark in colour and light in weight. Infection on mature berries caused cracking of the rind. The climate of Vellanikkara tract is typically monsoonic, consisting of South West and North East monsoons. The fresh leaf infection by the pathogen was found during the pre-monsoon period and the peak period of infection was during South West monsoon period. The intensity of the fresh leaf infection was found to be significant and positively correlated with number of rainy days total rainfall and averages of maximum and minimum temperature. Maximum disease index was observed during the South West monsoon period. The minimum disease index was observed during the warm dry periods. Maximum infection on the pedicel of the spike was found during the South West monsoon period. The coefficient of simple correlation of the pedicel infection with weather parameters namely number of rainy days, total rainfall and averages of maximum and minimum relative humidity were significant. The berry infection commenced during the late part of the South West monsoon period. Mature berries got more infection than immature berries. Out of seven fungicides tried, in vitro one per cent of Bordeaux mixture, Difolatan 2000 ppm, Antrocal 2000 ppm and Bayleton 2000 ppm gave cent per cent inhibition of the fungal growth. In the field one per cent of Bordeaux mixture was found to be the most effective fungicide in controlling the disease, followed by Difolatan. Maximum yield of pepper was observed in Bordeaux mixture treated plot followed by Difolatan.