questions: .asking about control of black rot  
 answers: cultural control: prune or skiff the severely affected sections. improve aeration by lopping side branches and ‘matidals’. thin out dense shade and improve drainage. give alkaline wash after pruning. shorter pruning cycle helps in minimizing infestation.
chemical control: drench thoroughly all the stems and decomposing pruning litters below the bush with copper oxychloride (blitox 50/blue copper 50/dhanucop) @ 2 grams per liter one week after the first spell of rainfall in february/march