Rhododendron Care and Troubleshooting. If you can’t scrape it off, it is more likely to be one of the Rhododendron diseases that will eventually kill the plant. (syn. Dwarf Rhododendrons 1m & under; Tall Hybrids; Shop by Price. Informational table showing disease name, symptoms, pathogen/cause, and management of Azalea and Rhododendron diseases. Usually, when problems do occur, they can be traced back to the plant's environment. Save For Later Print. P. Kumm. Diseases of Rhododendron (Rhododendron spp.) There are large and small flowered varieties. … It happens during the late summer, when flower buds are developing. The rhododendron disease, which is represented in the photo, is distinguished by the formation of fungal black fruit bodies on the surface of the spots; therefore, it is treated by cutting off the affected areas and treating the shrub with Bordeaux mortar or Camulus. Many diseases and other problems can be prevented by following the recommended cultural practices for proper planting and care. Modern varieties tend to reach only 2 metres. They grow from a height of 50cm up to 4 metres. According to the Reader’s Digest Guide, you should spray the plant with insecticidal soap to prevent this problem. Shop by Size. Over time, the defeat brightens, cracks and crumbles. The rest of the plant probably won’t be looking very healthy either. The wood of a recently killed branch is lighter brown than the … Diseases and pests of rhododendrons; Images of diseases and pests of rhododendrons This page was last edited on 15 March 2020, at 17:06 (UTC). Root & Crown Rot Disease Symptoms Pathogen/Cause Management; Botryosphaeria canker: Rough, sunken, dark-brown areas form around wounds or natural openings in the bark. 3 - 4 year $30 - $39; 4 year old $45 - … When rhododendrons and azaleas are properly planted and maintained, insects and diseases are less of a problem. D. M. Benson, primary collator (last update 5/29/2015) ALGAL DISEASE Leaf spot and stem gall Cephaleuros virescens Kunze ex E. M. Fries BACTERIAL DISEASE Crown gall Agrobacterium tumefaciens (Smith & Townsend) Conn FUNGAL DISEASES Armillaria root rot (Shoestring root rot) Armillaria mellea (Vahl:Fr.) The most common pests, diseases, and problems of Rhododendron and Azaleas can be easily resolved. Updated: July 31, 2016. More information on successfully growing azaleas and rhododendrons is available in the fact sheets HGIC 1059, Azalea Care; HGIC 1058, Azalea Planting; and HGIC 1073, Rhododendron. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. Rhododendrons are evergreen, flowering from late autumn to early summer. Free rhodo consultation : WE ARE OPEN 10-4 PM 7 DAYS UNTIL THE END OF NOVEMBER : Login/signup : Shopping Cart cart(0) Home; RhodoClub; SHOP. Reply. Framing the spot may be brown depending on the type of pathogen. In this case, you may want to take the Rhododendron out to prevent the disease from spreading. Please contact us for help and advice. Articles. Janet says: May 8, 2019 at 8:45 pm . Rhododendron leafhoppers spread a bud-blast disease; buds die and are covered with spiny, black fungal spores. Rhododendron Bud Blast Disease. The height they reach can depend upon climate and soil conditions. Two diseases, branch die-back and Phytophthora root rot in particular, are opportunistic this way.