Prevention and control measures in sooty blotch, Wei Zi

① Horticultural control: strengthen cultivation management and arrange planting density reasonably; Pruning diseased branches and redundant branches in time is beneficial to ventilation and light transmission, thus enhancing the potential number and reducing the incidence rate. Before taking medicine in potted Lagerstroemia indica at home, the diseased leaves can be removed or the moldy layer on the leaves can be washed with clear water, which can play a certain preventive role. ② Chemical control: Controlling aphids and scale insects is the key factor to control sooty blotch. For fields with serious diseases last year, lime-sulfur mixture with Baume degree of 3-5 can be sprayed before spring germination to eliminate the source of overwintering diseases. Spraying 70% thiophanate-methyl wettable powder 1000 times, 80% zineb wettable powder/500 times and 20% triadimefon or 1% bordeaux solution100 days for plants damaged by sooty blotch in their growth period from mid-May.