The honeysuckle is a vigorous shrub or vine plant that is part of the Caprifoliaceae family. Honeysuckles originate in the northern hemisphere. They are extremely hardy and tolerant towards heat. Many varieties of honeysuckles produce flowers that are shaped similarly to bells and have soft, sweet scents. These flowers emit an edible nectar that has a sweet taste. As with most plants, there are various different diseases that could affect honeysuckles.
Powdery mildew is a fungal disease that occasionally affects honeysuckles. Some symptoms of powdery mildew include a gray or white dusty layer appearing over the surfaces of the honeysuckle's leaves, or the development of inconspicuous, powdery white circles on the leaves. This growth can often be eliminated by simply rubbing the leaves together. Powdery mildew usually shows up later in the cultivation season, particularly in humid areas. This disease can be treated by the removal and destruction of all parts of the honeysuckle that are infected. Some ways to prevent powdery mildew from occurring in the first place include pruning and thinning to enhance air circulation and not watering the plants from above. In severe cases, fungicides can also be used. The fungicides should consist of ingredients such as neem oil, potassium bicarbonate, copper and sulfur.
Leaf scorch is a physiological disease that affects many different varieties of plants, including honeysuckles. There are many potential causes for leaf scorch, such as compaction of soil, low-quality soil, drought and insufficient nutrients. Some signs of this disease are discoloration of the tissues located alongside the margins of the leaves, or between the primary leaf veins. The tissues tend to become darker or yellow in color. Sometimes angular, dark patches appear in the areas of discoloration, as well. Whole leaves also might turn a brownish color, and wither up (in serious cases of leaf scorch). Twig dieback also can occur. With the first signs of leaf scorch, it is beneficial to apply copper-based fungicides in order to stop the disease from spreading. This prevents germination of the fungal spores. Since the fungus overwinters in the leaves that have fallen from the plant, the only other control method that is necessary is the removal of the leaves entirely.
Sooty mold is a fungal disease that is characterized by its dark black, charcoal-reminiscent appearance. Sooty mold shows up as a jet-black layer on the surfaces of plants' branches, twigs, leaves and even their fruits. This fungi appears on the sticky and sweet honeydew that is emitted by insects such as whiteflies, scale, mealybugs and aphids. A thick coat of sooty mold also could appear on twigs and needles for more than just one cultivation season. One method of sooty mold treatment is using neem oil, which is a type of organic pesticide, insecticide and fungicide. This oil can control insects such as those that emit honeydew, as well as their fungi. It is entirely non-toxic. Insecticidal soaps and systemic insecticides also can be used to eliminate sooty mold.