This Azalea Formosa has been lush, green, and growing well since I transplanted it last fall. Yesterday, I noticed a leaf has developed a white patch on it. All the other leaves are unaffected and still dark green. Any idea what might be happening?
1st pic is of the leaf in question. 2nd pic is of the bush as a whole.
Hi Savvy, looks like spray from weed killer OR sun burn, or tunnelling insect, the type that tunnel in between the layers of leaf flesh.
I would CUT OFF the said leaf, Take it indoors and examine it by holding up to a light bulb, see IF there is any tiny lumps between the leaf (like looking for a wood splinter between the layers of skin on finger) OR sharp knife and cut the leaf, this will expose the OPEN layers, then try peal the layers to see IF you can expose the little burrowing (LEAF MINER) if still no luck with finding that, I would go feed the plants with a feed specially made for ACIDIC plants, maybe it's the start of some form of nutrients deficiency. Chlorosis turns the leaves yellow but, the veins remain green normally, IF you take the leaf to the garden store IF there's no bugs found, they will tell you what type of additive is required, BUT this will only be a temp solution IF the soil is too alkaline and not acidic enough for Rhododendrons / Azalea's. It's always wise to keep taking a soil test every season so you know what is needed to keep the plants growing well and healthy, especially IF you have manually tried to change the PH of the soil as watering causes additives to leech out of the soil as they are NOT naturally present.
I have to be honest, after bout a year growing OK, I don't think it's anything serious and can only suggest keeping a close eye on the plant for further damage of the same type, these MINING insects don't arrive in one's or twos, you normally find several light patches on same plant.
Hope this Helps. Kind Regards.
WeeNel.
