STANDARDIZATION OF ISOLATION TECHNIQUES FOR CEPHALEUROS PARASITICUS KARST, A PATHOGENIC ALGA IN TEA PLANTS

摘要

Among the leaf diseases in tea plants, red rust caused by a pathogenic alga Cephaleuros parasiticus Karst is found to be very important and more serious in tea plantations. Although the disease is known for over 40 years in all the tea growing countries, the disease has become a major problem only in recent years on the estates now resort to large scale replanting, infilling and inter row planting to increase production and productivity. No efforts are being made so far to isolate and study the culture characteristics of the alga under in vitro condition. It is in. this scenario the present investigation has been proposed to isolate the pathogen from infected leaf maierials The infected leaves will be washed with Tween 20 and surface sterilized using (15%) Mercuric chloride solution followed by repeated washing with sterile distilled water. The infected portion is cut into small pieces using sterile scissors and transferred to the culture vials containing Bristol medium, fhe culture vials are maintained at a temperature of 25±2°C under built in white fluorescent light at a photon flux density of 30-50 µEm2"S-2 with a photoperiodic regime of 16 hrs light and 8 hrs dark cycles. The promiment algal filaments emerging from infected portion will be transferred to fresh algal broth as well as on solid medium for further grcnvth. The present study mav be useful to develop an easy, reliable and reproducible technique for culturing this alga. Moreover, it will also be useful to study the culture characteristic features, life cycle and genetic diversity of C parasiticus, besides to screen various fungicides and biocontrol agents to control the pathogen very effectively under in situ.