DO YOU HAVE AZALEAS AND CAMELLIA SHRUBS?
This past week I have had two different guests come into the garden center with samples of gall on their azaleas. Not to make light of this disease but I love using the tagline “you have some gall” with our guests. We both laugh.
On a serious note, having gall on these plants is more common than you may think. Gall is popping up on the plants now as we begin to warm up more consistently along with the higher humidity. The samples show thick, distorted leaf growth.
Exobasidium vaccinia is a wind-borne fungus that can overwinter on bark and within buds. This fungus causes large fleshy growth up to 4 times the size of normal leaves. This fungus gall is commonly referred to as azalea or camellia leaf gall.
Once the leaf gall forms on your azalea or camellia the best treatment is to pluck off the malformed leaves, put them into a plastic bag, and toss them in the garbage. Do not drop them on the ground. This disease relies on airborne spores produced in the whitish mold on the surface of the galls. Once the spores are formed and released, they are blown and washed to leaves where they will cause new infections next year.
BE SURE TO PICK OFF THE LEAF GALL BEFORE IT BEGINS TO TURN WHITE. THIS IS THE STAGE WHEN NEW SPORES ARE PRODUCED.
There is no effective or practical fungicide to control this disease. However, it is thought that a weekly application of NEEM OIL can reduce the number of viable mold spores.
So, if you have azaleas or camellias then take some time to inspect these plants for any evidence of gall. This disease is just at the beginning stages here in May.