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Kabatina and Phomopsis Tip Blight
Need to know:
- Disease affects the branch tips, causing color change to yellow or brown.
- In nursery setting disease can be devastating but otherwise, damage caused on junipers are not very significant.
- Disease is more prevalent in moist and warm conditions.
- Preventative measures include planting resistant varieties and carrying out healthy practices.
- No chemical control is required.
Overview of Tip Blight
Tip blights cause the tips of cedar branches to die. Often, small black dots, fruiting structures of the fungi that cause tip blights, are visible on the affected needles.
Junipers are particularly susceptible to Phomopsis and Kabatina tip blight, two damaging fungal diseases that cause needle browning and dieback at the tip of the branches. Tip blight of junipers is caused by two different species of fungi, Phomopsis juniperovora and Kabatina juniperi, which cause similar symptoms in the affected plants. However, the two diseases differ by the time of the year when they occur and their development on the plant.
Symptoms of Kabatina & Phomopsis Tip Blight
Symptoms begin with the last 2-6 inches of the branch tips turning a dull green that transitions into a red or yellow color. Gray to silver color lesions develop at the base of the infected tip. Dead tips eventually break off from where the lesion is. The disease usually doesn’t cause a lot of dieback in foliage but after repeated years of infection the branches can result in witches’ broom formation.
Phomopsis tip blight can be particularly devastating in nursery settings when it affects seedlings of young grafted stocks. Otherwise, the damage it causes on junipers in natural or landscape settings is not very significant.
Signs of Tip Blight
Small black fruiting bodies (acervuli) can be seen under slight magnification at the base of diseased tips and usually become visible 2-3 weeks after symptoms become apparent.
Disease Cycle of Kabatina and Phomopsis Tip Blight
Phomopsis tip blight usually appears from middle April through September and causes the new growth at the tip of the branches to turn dull brown and finally ash-gray. Often, small lesions appear around the twig. Minute black spots may be observed on the lesions; these are the fruiting bodies or spore producing structures of the fungus. The spores are dispersed by splashing or wind-driven rain. Usually Phomopsis spores infect new foliage tissue during spring (April-early June) and late summer (late August through September) under favorable environmental conditions such as high humidity. Even though Phomopsis tip blight may damage branch tips and slow down plant growth, it seldom causes death of the plant. Death, however, may occur if the affected plant has experienced extensive damage and stunted growth due to blight early in the season.
Symptoms of Kabatina tip blight appear earlier in the year, usually during February and March. This disease also affects the branch tips, which in this case change color to yellow or brown. The affected tissues on the twigs show an ash-gray coloration and, like in Phomopsis tip blight, are covered with small black fruiting bodies where spores are produced. Later in the spring (May-June), the affected foliage drops, but no further infection occurs until later in the fall months, when Kabatina spores may infect wounded or damaged tissues of juniper branch tips. The blight symptoms will then be visible early the following spring.
Type of Sample Needed for Diagnosis and Confirmation
The Iowa State University Plant & Insect Diagnostic Clinic can help you to investigate and confirm if you plant has this disease. Please see our website for current forms, fees, and instructions on collecting and packing samples. Contact information for each states diagnostic laboratory for U.S. residents. If your sample is from outside of Iowa please do not submit it to the Plant & Insect Diagnostic Clinic without contacting us
Management of Tip Blight
Both blights are more prevalent in moist and warm conditions. Whenever possible, resistant varieties should be planted to prevent these diseases, and healthy practices implemented. These include adequate spacing between plants to allow for sufficient air flow, avoiding prolonged night time watering or using overhead sprinklers, and pruning and discarding any diseased material. Plants are particularly susceptible to tip blight infection when stressed or wounded by insects or mechanical injury.
Both blights, in general, do not require any chemical control in natural established plantings. For more information on juniper, diseases see the publication tilted Juniper diseases free to download at the extension store
See this article about tip blights on juniper.
Fungicide applications may be avoided by following good Integrated Pest Management practices like those listed in this encyclopedia article. Often, the only preventative application is effective to manage plant diseases. If the problem requires a fungicide, state law requires the user to read and follow all labels accordingly. For more information, read Proper fungicide use.
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