Honeysuckle is a hardy plant that is not plagued with any major disease. Those diseases reported on honeysuckle rarely become severe enough to warrant control fungicides.
Leaf Spots (fungi – Cercospora spp., Septoria sambucina and others): Avoid overhead irrigation. If spraying is necessary, apply a recommended fungicide.
Leaf Blight (fungus – Glomerularia lonicerae): This fungus blights the leaves during rainy seasons with light-colored, circular spots that can cause leaf death. Control by spraying with recommended fungicides.
Powdery Mildew (fungi – Microsphaera alni and Erysiphe polygoni): These powdery mildew form a white, powdery coating on both leaf surfaces and young stems. Microsphaera is rather widespread in the United States while Erysiphe occurs primarily in the western United States. Control by spraying with recommended fungicides.
Cotton Root Rot (fungus – Phymatotrichum omnivorum): Honeysuckle is only moderately susceptible to Cotton Root Rot.
Leaf Spots or Blights (fungus – several): Small-to-large round to irregular spots and blotches on leaves and pods. Leaves may be blighted and drop.
Crown Gall (bacterium – Agrobacterium tumefaciens): (See section on Crown Gall)
Rarely Observed Diseases: Honeysuckle is also susceptible to thread blight, caused by the fungus Pellicularia koleroga, twig blight caused by the fungus Phoma mariae, rust caused by the fungus Puccinia festucae, hairy root caused by the bacterium Agrobacterium rhizogenes, and crown gall caused by the bacterium Agrobacterium tumefaciens.