Answer: What you describe sound like scale insects. Scale is difficult to control. Because these insects are concealed, contact sprays won?t provide long lasting results, as
many will be missed by the spray. There isn?t any research to show which product (insecticide) will do the best job. My best bet is imidacloprid as found in Bayer
Advanced? Tree & Shrub Insect Control. This product is applied per label directions as a root drench and will move via the root system throughout the internal
plumbing (vascular pipelines) of the plant. It is a slow acting chemical and it may take a few weeks to see results. This systemic approach will not directly harm the beneficial insects that are attacking the scale. (I usually see a few lady beetles on the scene helping to reduce this pest.) An alternative is to dab individual scales with a Q-Tip dipped in rubbing alcohol. This will kill the pests and in a few weeks you can peel them off with your fingernail. Best wishes with your project!
Q&A Library Searching Tips