Fuchsia gall mite—Aculops fuchsiae
Feeding by this mite (family Eriophyidae) causes fuchsia leaves and shoots to distort, thicken, and form irregular galls.
Because of their microscopic size their characteristic plant damage as described below is used to identify the problem as feeding by fuchsia gall mite. Aculops fuchsiae is the only eriophyid species known to infest Fuchsia species at damaging levels.
The mites are pale yellowish, carrot shaped or wormlike, and 1/100 inch (0.25 mm) or less in length. They have two pairs of thin legs protruding from their head (wider) end. They resemble other Aculops species of the same coloration. Except for when the mites are found in abundance on fuchsia, they can be discriminated to species only by expert preparation and examination of microscopic characters.
Eriophyids develop through four life stages: egg, protonymph, deutonymph, and adult. The protonymph and deutonymph are sometimes respectively called larva and nymph. The mites live and reproduce within the folds of galled tissue and among plant hairs. As infested plants grow, some mites leave the galls and move upward to attack new terminal growth and blossoms. The mites occur on growing tips year-round and in flowers whenever present. The mite prefers cool growing conditions and its abundance and reproduction are reduced by warm temperatures.
Each adult female lays a total of about 50 eggs, which hatch in about 1 week. Nymphs feed for about 2 weeks before maturing into adults. The life cycle from egg to reproductive adult is completed in about 3 weeks. There are several generations per year.
Fuchsia gall mite feeding distorts and thickens leaves and terminals and causes infested foliage to redden. Flower production is reduced and when the mites are abundant, over time they can stop all new growth. Because fuchsias and the mite develop best where summers are cool, fuchsia gall mite is mostly a problem in Coastal California and interiorscapes.
Predatory mites especially Neoseiulus (=Amblyseius) californicus significantly suppress the mite's abundance where miticides and broad-spectrum insecticides are not applied. However, biological control is generally not satisfactory on fuchsia cultivars most susceptible to this pest.
To reduce damage, grow only resistant fuchsias and consider replacing susceptible species. To manage the mite
- Do not exchange fuchsia plant material with others and obtain plants only from a quality, commercial supplier.
- Keep infested plants in a cool windless place and isolate them from other fuchsias if possible because the mites can spread with the wind as well as on infested clothing, hands, plants, and tools.
- Practice excellent hygiene: change clothing, clean shoes, wash hands, and clean tools with alcohol after contact with infested plants.
- Pinch off or prune and remove all infested parts of the plants and destroy or dispose of them away from plants. Do not compost fuchsia plant parts.
- Spray the remaining plant parts with a miticide (acaricide) labeled for the plant or site of application.
- Try to keep hardy fuchsia varieties outside during colder weather, which may help to kill off the mites.
If pesticide will be applied, first prune or pinch off and destroy all infested (damaged) leaves and terminals. Then apply horticultural (narrow-range) oil or insecticidal soap at internals, such as 2 to 3 weeks apart.
Certain effective miticides such as carbaryl are only available to professional applicators and can only be applied outdoors. Take indoor plants outdoors and after the application do not bring plants back inside until the spray has completely dried. Be aware that carbaryl is highly toxic to bees and natural enemies. Consider covering outdoor plants with cheese cloth or other screening after the application to exclude bees and hummingbirds on which the mites can hitchhike. Consult Pest Notes: Hiring a Pest Control Company for help in how to select a company and discuss their IPM plan. For example, discuss in advance with the company how they plan to control your mite problem.
For more information see Aculops fuchsiae (Fuchsia Gall Mite), Fuchsia Gall Mite Management (PDF), and Kill All the Gall Mites.
Adapted from the publications above and Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, University of California Statewide Integrated Pest Management Program (UC IPM).
Terminal distorted and thickened from fuchsia gall mite feeding.
Leaves distorted and thickened from fuchsia gall mite feeding.
Magnified adults and nymphs of fuchsia gall mite.