Identification and Control of Brown spot of Poplar

Poplar brown spot is a common leaf disease, which mainly harms Populus tomentosa, Populus tomentosa, steamed bread willow and so on. At the initial stage of the disease, there are small yellow-brown spots on the surface, which gradually expand, the edge color is lighter and neat, to the later stage, the center of the lesion becomes brown, and there are black spots on it. After the black spot breaks, the conidia are released and blown to other leaves by the wind to re-infect. The disease is the most serious in July and August, and most of the disease spots are connected into pieces, which often cause the leaves to scorch and fall off in September. When the planting is too dense and the temperature and humidity are high, the disease is more serious. Prevention and control methods: 1. Sweep deciduous leaves in summer and autumn, compost or burn at high temperature to eliminate pathogens. 2. Spray 6-7 times 160-200 times limewater or 500 times 65% zinc wettable powder from June to September. 3. Do not plant too densely, pay attention to pruning, make the forest ventilated and transparent, and reduce the conditions of the disease.