The reason why the leaves of crabapple have yellow spots

1. Infection with rust

Cause: This disease occurs around April every year. At first, there will be orange-yellow spots on the leaves, and then the spots will gradually expand. The diseased area will also become thicker, and the back part will bulge. As the disease progresses, yellow-white spores will grow in the raised areas, which will eventually cause the leaves to die.

Solution: Take protective measures first to avoid planting together with other tree species such as pine, cypress and arborvitae to prevent the disease from getting worse. Remove the diseased leaves promptly, gather them together and destroy them. If the condition does not improve, spray with triadimefon emulsifiable concentrate, amylopectin emulsifiable concentrate and other pesticides.

2. Infection with brown spot disease

Cause: This disease also causes yellow spots on the leaves, which is relatively common. In the early stage of the disease, white spots will appear on the front of the leaves, then gradually expand and turn yellow-brown, and the leaves will also burn and fall off, which has a great impact on the plant.

Solution: Do a good job of prevention and strengthen ventilation management. If you accidentally discover that the plant has been infected with the disease, you need to pick off the diseased leaves in time, collect them together and burn them to prevent the further spread of the disease. Spraying Bordeaux mixture once can effectively control the disease.