Fragrant honeysuckle blossoms signal the beginning of spring. The season also means the reawakening of the fungus that causes honeysuckle leaf blight, notes the Iowa State University Extension. Honeysuckle leaf blight is common in the northeastern and north central U.S. and affects most varieties of honeysuckle.
The fungus Insolibasidium deformans causes honeysuckle leaf blight. The fungus is dormant throughout the winter, then strikes new leaves as they sprout. The disease can limit plant growth.
Leaf blight turns leaves yellow. As the disease progresses, leaves turn brown, rot and then dry out. The leaves can roll up or twist and fall off. The fungus also deposits a white powder on the leaf's underside, states ForestPests.com.
Honeysuckle leaf blight fungus thrives among plants that do not have adequate air circulation around them and where the humidity is high, notes the Iowa State University Extension.
To reduce the risk of blight, don't plant honeysuckle bushes close together or prune existing bushes regularly. Cut back on watering in periods of high humidity or heavy rainfall.
If your honeysuckle plants are infected with leaf blight, prune the affected branches and dispose of the debris to deprive the fungus spores of a breeding ground. You can also apply a copper fungicide, such as Fore, if your plants are infected with leaf blight, suggests the Iowa State University Extension.