Cherry leaf spot
Blumeriella jaapii
Also Known As - Leaf spot CherryWhat is a Cherry leaf spot (Blumeriella jaapii)?
Blumeriella jaapii is a fungal pathogen causing cherry leaf spot, affecting cherry trees, as well as plums. Symptoms include circular lesions turning into "shot hole" patterns, yellowing, and premature leaf drop. Tart cherries are particularly vulnerable, experiencing purple-to-brown spots with leaf holes. Leaf loss increases winter injury risk, slows spring growth, and decreases summer fruit production.
How does Cherry leaf spot (Blumeriella jaapii)?
Blumeriella jaapii survives winter in fallen leaves and releases ascospores in early spring. Germination occurs on wet leaves at 58-73°F. Leaf spots emerge within 10-15 days, with undersides producing spores. Wind and splashing water disseminate spores, causing new infections. Rainy seasons in May and June expedite the spread. By late summer, mature leaves become susceptible, potentially resulting in complete defoliation.
Symptoms
1 - Plant Health
• Blumeriella jaapii weakens infected plants, making them more susceptible to other stresses and diseases. • Severe infections can lead to defoliation, reducing photosynthesis and overall plant vigor. Causes blemishes and spotting on fruit, reducing market value. • Reduces fruit quality and yield, impacting the economic value of cherry and plum crops.
2 - Impact on Soil
Blumeriella jaapii has an indirect impact on soil and the environment. Defoliation contributes to increased nutrient cycling and organic matter accumulation as fallen leaves decompose.
Solutions
1 - Cultural Control
• Rake up and destroy infected leaves, ensuring they are completely decayed before spring. • Encourage leaf decomposition through practices like mowing or flailing. • Apply urea to fallen leaves in autumn to enhance decomposition. • Compost or properly dispose of the collected leaves. • By removing fallen leaves, you eliminate a potential source of disease spores. This reduces the chances of fungal survival and spread in the next growing season.
2 - Chemical Control
• Fungicides for controlling Cherry leaf spot are Bonide Captan 50 WP, Bravo Weather Stik, Captan 80 WDG, CaptEvate 68 WDG, Cevya, Cueva, Eagle 20 EW, and Echo 720 among others. • Managing Fungicide Resistance: Overuse of myclobutanil can lead to resistance development in leaf spot fungi. To prevent resistance, alternate between myclobutanil and captan for repeated fungicide applications. • Copper-Based Fungicides: Fungicides containing copper may offer some protection against leaf spot infection. Certain copper fungicides are approved for organic production. Note: Please follow label instructions and consult local experts for specific recommendations.
