Answer: What you describe sounds damage from the fuchsia gall mite (Aculops fuchsiae).
This pest was first observed in San Francisco in 1981, and is thought to have come from Brazil. The mite is microscopic, 0.3 millimeters long, and uses its piercing/sucking mouthparts to feed on young leaves and blossoms.
As it feeds, it injects a toxin into the plant tissues, causing distorted and stunted growth. Infected tissues often become reddened in appearance. The mites live within the galls that are formed, making control difficult.
It is thought that the mites are spread by wind, bees or hummingbirds.
Control of the fuchsia gall mite depends somewhat on the susceptibility of the particular species or cultivar of fuchsia.
In most cases, cultivars that suffer from severe infestations are managed more easily by disposal than the repeated application of pesticides.
If you are willing to give that extra effort, the fuchsia gall mite can be brought under control.
Highly susceptible varieties will require a two-phased strategy. First, all distorted foliage must be cut off a few inches below the damaged section, approximately two leaf nodes. Dispose of this in a sealed plastic bag in the trash. After pruning, spray the remaining plant with the miticide endosulfan, sold under the trade name Thiodan. Repeat the spraying once a week for three weeks.
Carefully monitor your plant as it grows and repeat this process if the mites reappear. Read and follow label directions when applying pesticides. Moderately susceptible varieties will show only minor distortion, and pruning the affected sections should be adequate control.
Low-susceptibility or resistant varieties will not be affected by the mite at all. These cultivars should be used whenever possible. A number of these resistant species are characterized by small leaves and flowers. These species types had not been widely available, but are becoming more so. Large-flowered cultivars with great names like Baby Chang, Chance Encounter and Space Shuttle have also shown low susceptibility to the mite. All varieties will benefit from an application of horticultural oil while dormant, to smother mites or eggs overwintering in the bark.
The University of California Cooperative Extension has information about the fuchsia gall mite, including a list of varieties ranking their susceptibility. The telephone number for the extension in Santa Clara County is (408) 299-2635. In San Mateo County the number is 726-9059. Ask for leaflet 7179.
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