Rhododendron Borer Larva in Stem (Bark Cut Away)

The rhododendron borer is a bark boring insect that forms galleries under the bark and can cause considerable damage. Plants appear drought stressed and show dieback in entire areas. Holes can be seen at limb crotches. The rhododendron stem borer is a similar bark boring insect that attacks the twigs and stems of plants. Damage can be seen in curled leaves with callus tissue at mid-vein. Clusters of small holes are visible at twigs and stems. In both cases, sanitation pruning is the first step, after which spray treatments to the bark are recommended