Diseases and Pests of Red Rhododendron and Their Control

Diseases and Pests of Red Rhododendron and Their Control

Leaf blight

In the early stage of the disease of red yew, you can spray 600-800 times diluted 25% carbendazim wettable powder, or 600 times diluted 70% mancozeb and other agents. Generally, spray 2-3 times every 15-20 days.

Perforation disease

For the prevention and control of perforation disease, remove and burn diseased branches and leaves in autumn to reduce the source of infection; strengthen management, increase the application of organic fertilizers and phosphorus and potassium fertilizers, and do a good job in preventing drought and waterlogging, which will help enhance tree vigor and thereby improve the plant's own resistance. Before and after the red yew trees unfold their leaves, especially for seedlings, it is necessary to spray 3-5 degrees Baume lime sulfur mixture, or 500 times diluted 65% mancozeb in time; for the prevention and control of bacterial perforation disease, zinc sulfate lime solution can be sprayed after the leaves unfold.

Leaf spot

For the prevention and control of leaf spot disease, it is also necessary to cut off and burn seriously diseased leaves in autumn and winter to reduce the source of infection; control the reasonable distance when planting, not too dense, and prune appropriately to maintain good ventilation and light conditions; avoid wetting the leaves when watering, it is best to do it in the morning on a sunny day; chemical control can be done in the early stage of the disease, spray 75% thiophanate-methyl wettable powder 700-800 times liquid once every 10 days or so. When the disease develops more seriously, you can spray 50% carbendazim 1000 times diluted for prevention and control.

aphid

For the prevention and control of aphid pests, you can use 1500 times diluted 20% cypermethrin emulsifiable concentrate for spraying, or apply 1000-1500 times diluted 50% aphidicide emulsifiable concentrate, or 1000 times diluted 80% dichlorvos emulsifiable concentrate for effective prevention and control.