Influence of Biotic and Chemical Plant Inducers on Resistance of Chilli to Anthracnose

Abstract

The potential of biotic and chemical plant inducers to trigger the resistant in plant against disease was investigated.A biotic inducer as Trichoderma harzianum and chemical inducers as salicylic acid and Bion^® were tested for their induced resistance ability to protect anthracnose disease on two
tested chilli cvs. Mae Ping and Man Dum in both seedling and mature stages. The necrotic symptom development on seedling of both tested chilli varieties after treated with Bion^® 0.05 mg a.i./ml was significantly lower than the others. The potential of anthracnose management on chilli cv. Man Dum was also treated by T. harzianum at 108 spore/ml and salicylic acid at 1 mM. Treatments with any plant inducer did not lead to an increase activity of polyphenol oxidase in chilli cotyledon 1, 3 and 5 day after challenge inoculation. In field experiment, the result showed that the foliar sprays with any of plant inducer reduced the infection percentage of anthracnose on chilli. Bion^® also showed the best percentage of disease reduction compared to the untreated treatment at 76.3% and 75.9% on both chilli varieties, whereas in treatment of 108 spore/ml T. harzianum and 2 mM salicylic acid were reduced 24.2, 57.4% and 19.8, 36.6% respectively. However, fruit yield of Bion^® treatment was very low and significantly
different to control. The phytotoxicity occurred at high concentration. T. harzianum and salicylic acid treatment showed the fruit yield to be significantly increased in comparison with the control on chilli cv. Man Dum, but not on cv. Mae Ping. All plant inducers did not affect to fruit fly infestation on both varieties under field conditions.