JORHAT: The heat wave prevailing since the past few days, coupled with minimum amount of rainfall, has worried experts of Tocklai Tea Research Institute. In year 2018, till July 31 a total of 1083.8mm rainfall was received as compared to 1399 mm till July 31 in 2017. Moreover, if the temperature reaches about 35 degree Celsius, photosynthesis might stop as in a year about 2000 mm rain is required with minimum temperature of 32 degree Celcius to 35 degree Celcius, said sources from the meteorology department of Tocklai. During the peak season between July to August, rainfall was one inch lesser than that required by tea bushes. As a result, tea bushes have been infected by many dreaded diseases and this has become a cause of concern for small tea growers and planters, said Dr. Pradip Baruah, a senior scientist of Tocklai Tea Research Institute.