What should I do if my Japanese red leaf tree Lagerstroemia indica gets black spot disease?

Occurrence regularity and control measures of Lagerstroemia indica sooty blotch;

Occurrence regularity: sooty blotch pathogenic bacteria overwinter on diseased leaves and branches in the form of mycelium or ascomycetes. Because the mucus secreted by Lagerstroemia speciosa and Lagerstroemia speciosa will provide nutrition for pathogenic bacteria in sooty blotch, generally, a large number of sooty blotch will occur after the occurrence of these two pests. However, from late June to early September, the damage of Lagerstroemia speciosa and fast-growing Lagerstroemia speciosa in Japanese red leaves reached its peak, and the high temperature and humidity at this time were also conducive to the occurrence of diseases, so spring (caused by overwintering pathogens) and autumn (caused by Lagerstroemia speciosa and Lagerstroemia speciosa) reached their peak.

Prevention and control methods:

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: The key factor to prevent sooty blotch is to control aphids and scale insects (which will be introduced later). 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. 70% thiophanate-methyl wettable powder 1000 times solution or 50% solution can be sprayed on the plants harmed by sooty blotch during the growth period. The above information was compiled by Jiangxi Agriculture, Countryside and Farmers. For more symptoms and effective prevention methods of sooty blotch of Japanese red-leaf trees, join: Jiangxi Sannong Hua Mu Garden Co., Ltd. V letter to understand, hope to help you!