The high-risk period for infection is when leaves are very young later in the season, leaves become resistant to the fungi, so there are no repeat cycles of infection in the same season. If defoliation does occur, the lost leaves will almost always be replaced by new ones within several weeks to a month. Less severely affected leaves may remain on the tree all season. Severe infection, along with defoliation, may occur if these weather patterns persist. Optimal conditions for this pathogen are over 12.5 hours of leaf wetness and temperatures below 61 degrees F. Infection occurs on developing leaves early in the spring when buds open if environmental conditions are favorable for the disease. Leaf blister and anthracnose can occur on the same tree and even on the same leaf. 2) The rounded shape of the spots and blistering distinguish this disease from maple anthracnose, which produces irregularly shaped brown spots or blotches that follow the veins of leaves and is caused by a different fungus. 1) Multiple infections will cause the leaf to become distorted. Pests and diseases: Amur maple is relatively free of pests and diseases, but can be affected by leaf spots. There are several cultivars including a shrub form. It grows well in a range of soils and growing conditions and can be easily shaped by pruning. The leaf blisters turn black, often lighter-colored in the center. It is a hardy tree that seems to have a higher tolerance for shade than other maple species. Symptoms include grayish brown-to-black irregularly-shaped, slightly-raised but not always obvious blisters on the leaves. The disease may go unnoticed until a large number of leaves are severely infected and begin to fall from the tree. Look for top varieties such as Red Sunset, October Glory, Red Supersonic, Ruby Frost, and Columnar. Red maple grows at a moderate rate and makes a sturdy, beautiful shade tree. The causal agent is the fungus Taphrina carveri. A North American native, red maple trees form an oval crown of bright green leaves that turn fiery red in autumn. A foliar disease called leaf blister has been common on silver and red maples and their hybrids during the past few weeks.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |