Twig blights
Kabatina juniperi
What are Twig blights ( Diaporthe juniperivora and Kabatina juniperi)?
Juniper twig blight is a fungal disease that affects Juniperus spp. (juniper) plants. It is caused by two fungi called Diaporthe juniperivora and Kabatina juniperi. The disease is mainly found in western Oregon and parts of eastern Washington and nursery markets. It infects the current year's growth, causing tip dieback and foliar blight. Infected foliage turns red, brown, or ash-gray, with small lesions and black fruiting bodies. Severe cases can result in stunted growth and plant death
How do Twig blights ( Diaporthe juniperivora and Kabatina juniperi) occur?
Juniper twig blight is caused by fungal spores that can spread and infect juniper plants. The spores are produced by the fungi Diaporthe juniperivora and Kabatina juniperi. The disease occurs when the spores land on young juniper foliage during periods of high moisture and humidity, usually in the spring. The spores enter the plant through wounds, insect feeding, or mechanical damage. Once inside the plant, the fungi grow and cause damage to the current year's growth, resulting in tip dieback and foliar blight.
Symptoms
1 - Tree Health
• It causes significant damage, leading to dieback, loss of foliage, and potential death of branches or the entire tree. • The disease also negatively affects the visual appearance of affected trees, diminishing the aesthetic value of plants.
3 - Soil Health
Accumulation of organic matter from dead branches and foliage on the soil surface can occur, potentially altering soil conditions.
Solutions
1 - Plant Selection and Tree Health Maintenance
• Prune out and burn affected twigs and branches to remove infected plant material. • Avoid wounding the twigs, as wounds provide entry points for the fungus. • Avoid overhead irrigation or ensure that plants are not wet for extended periods, as moisture promotes fungal growth. • Practice proper spacing between plants to allow for good air circulation, reducing humidity and minimizing disease spread. • Choose and grow resistant cultivars when possible. • Select cuttings only from disease-free stock plants. • Follow good cultural practices, including balanced fertilization and proper plant care, to maintain plant health and resilience. • Monitor plants regularly for early signs of infection and take prompt action if symptoms are observed.
2 - Fungicide Application
• For treating Juniper twig blight, some commonly used fungicides include Cleary's 3336 EG (Group 1), CuPRO 5000 (Group M1), Heritage (Group 11), Kocide 3000 (Group M1), Mancozeb-based products (Group M3), Fore 80 WP, Protect DF, Mural (Group 7 + 11), Phyton 27 (Group M1), and Propiconazole-based products (Group 3). • Follow label instructions for proper application rates and timings. It's also recommended to consult with local agricultural extension services or professionals for guidance specific to your region and situation.
