Treating black spots on pear tree leaves, also known as Fabraea leaf spot, requires a combination of sanitation practices and chemical control. Fabraea leaf spot is a fungal disease that commonly affects pear trees, causing black spots to develop on the leaves. These spots can eventually lead to defoliation and weaken the tree if left untreated.
1. Sanitation: One of the first steps in managing Fabraea leaf spot is to practice good sanitation in your garden. This involves removing fallen leaves and debris from around the base of the tree. These fallen leaves can harbor spores of the fungus and increase the chances of reinfection. Flail mowing the leaves and brush can also help reduce the spores, as the mechanical action breaks them down. Proper disposal of the pruned branches and leaves is crucial to prevent the spread of the disease.
2. Chemical Control: While sanitation is important, it is usually not enough to completely control Fabraea leaf spot. Chemical control using contact fungicides is often necessary, especially in wet years or when the disease is severe. Begin spraying in the spring, just as the leaves begin to emerge, and continue treating every 7-10 days throughout the summer. Be sure to follow the instructions on the fungicide label for dosage and application timing.
3. Fungicide Selection: When choosing a fungicide, look for products specifically labeled for Fabraea leaf spot or pear tree diseases. Some common fungicides used for Fabraea leaf spot include copper-based products, such as Bordeaux mixture, and synthetic fungicides like chlorothalonil and mancozeb. It’s important to rotate between different fungicides with different modes of action to prevent the development of resistance in the fungal population.
4. Timing: Timing is crucial when applying fungicides for Fabraea leaf spot control. Start spraying in the spring before the disease becomes severe, as preventive measures are often more effective than curative treatments. Be diligent in maintaining a regular spray schedule, especially during periods of frequent rain or high humidity, which create favorable conditions for disease development.
5. Tree Health: Maintaining overall tree health is also important in managing Fabraea leaf spot. Ensure that your pear tree is receiving proper sunlight, water, and nutrients. Avoid over-fertilizing, as excess nitrogen can promote succulent growth that is more susceptible to disease. Prune the tree to improve air circulation and sunlight penetration, as this helps to reduce the humidity levels that favor disease development.
6. Disease Resistance: When planting new pear trees, consider selecting varieties that are resistant to Fabraea leaf spot. Some pear cultivars, such as ‘Moonglow’ and ‘Magness,’ have shown resistance to the disease. Planting resistant varieties can significantly reduce the need for chemical control and make management easier in the long run.
Treating black spots on pear tree leaves caused by Fabraea leaf spot requires a combination of sanitation practices and chemical control. Regular sanitation, including the removal of fallen leaves and debris, can help reduce the spread of spores. However, chemical control using contact fungicides is usually necessary to effectively manage the disease. Timing, fungicide selection, and overall tree health are crucial factors in successfully controlling Fabraea leaf spot.
