- Tree develops a brown haze
- Only on current years needles
- Black specs on affected tissue
Phomopsis causes tip blight on Juniper trees and shrubs. Current season's growth turns brown while two year or older needles remain healthy. Closer inspection of the needles will reveal tiny black specks in rows along the underside of the needle. Symptoms begin as early as mid April but may not appear until late summer. Repeated years of Phomopsis infection can cause stunting and decrease the trees vigor.
Phomopsis spores are produced in mid spring on previously infected needles. The spores are splashed to the susceptible growing tips where they infect, if exposed to water or high humidity. The fungus colonizes and kills only the new growth. Spores are produced on infected tissue beginning in early summer and are capable of causing new infections through September when water or high humidity are present at the infection site.
Control of Phomopsis blight relies on cultural methods. Select resistant Junipers for new plantings. In the landscape, maintain space around plants to allow air circulation and drying of the canopy. Irrigate in the morning when foliage has time to dry. Maintain proper soil fertility and control insects, like spider mites, that feed on branch tips. Prune out blighted branches, making sure to remove a few inches of healthy tissue behind the canker to make sure all of the pathogen has been removed. No chemical controls are registered for homeowner use against Phomposis.
Active Ingredients include: Copper salts, Propiconazole, Thiophanate-methyl
