Brown spots on plants
Both my small Bay tree/bush, and my small olive tree have small brown "spots" on the leaves which appeared last summer. We have them in our sun room for the winter. Question: What could that condition be, and how can I treat them? (See photos) Thanks,
Baltimore County Maryland
Looks like you have a scale infestation on the bay and olive plants. We also see webbing on the bay tree which indicates spider mites. Scale and mites are sucking insects. The infestation looks pretty severe. Make sure that you keep these plants away from other houseplants as the infestation can spread to other plants.
Wash off or crush any visible scale insects. Take the plants outside on a warm day about 60 degrees and spray thoroughly with a horticultural oil labeled for houseplants. Follow label directions.
Outdoors these insects are usually kept under control by beneficial insects. Spray your plants with horticultural oil or soap before bringing them in for the winter. http://extension.umd.edu/hgic/scale-insects-houseplants