Some species of honeysuckle are susceptible to a powdery mildew growing on the leaves. This will not usually injure the plant but may make it less attractive in your garden. Treating mildew on the honeysuckle is not difficult, but it will take time -- perhaps even multiple growing seasons. Knowledge on how to treat the powdery mildew will help you fight the plant disease with more vigour.
Start spraying your plant with a fungicide as soon as you detect the mildew if it is in the spring or summer. Read the package carefully to make sure that powdery mildew is listed on the package -- this means you can use the pesticide for this specific problem. Follow the directions on the package for application instruction.
Clear the area around your plant or transplant it to a new area to make the habitat more conducive to growing. The honeysuckle does best in full sun and well-drained soil, where the powdery mildew will not have a chance to grow. It also does not like to be crowded by other plants so, if possible, clear the area to allow the plant to breathe.
Water your plant thoroughly once a week during dry periods. Do not wet the leaves while watering. If the leaves have been wet by rain, do not move amongst your plants as this will only spread the mildew. Keeping your plant vigorous is the best defence against disease.
Prune off the diseased branches of the honeysuckle in winter when the plant is dormant. Rake up all the leaves and branches of the plant when finished and dispose of them immediately. Burning is the best method for disposal.
Continue applying fungicides, starting in the spring, and again prune in the winter. This will decrease the amount of spores able to infect your plant.
Do not over-fertilise your honeysuckle, as this will promote dense foliage growth limiting air flow in the plant.