Broom gall mite

Systematic position
The broom gall mite (Eriophyes genistae) is a member of the order Trombidiformes and the family Eriophyidae. These microscopic organisms are known as four-legged mites, and they are highly specialized parasites that live within plant tissues, inducing the formation of abnormal growth known as galls.

Host range
The primary hosts for this mite are species of the genus Genista (broom). While they are often found in wild broom thickets, they can also cause significant aesthetic and structural damage to ornamental broom plants in gardens and public landscapes.

Biology and lifecycle
The lifecycle of Eriophyes genistae is synchronized with the growth of the host plant. Adult females overwinter in bark crevices or dormant buds. As soon as temperatures rise and the plant begins to grow in the spring, the mites move to developing buds and begin feeding, which triggers the plant to develop galls where the mites live and breed.

Character of damage and impact
The most noticeable symptom is the formation of dense, abnormal galls on the tips of shoots or flower buds. These galls interfere with the normal development of the plant, stunting growth and reducing flower production. Severe infestations can weaken the entire plant, making it more susceptible to environmental stress and secondary infections.

Control measures
Managing Eriophyes genistae is challenging because the mites are protected inside the plant galls. Effective strategies include:

• Physical removal: Pruning and disposing of infested shoots before the mites migrate.
• Chemical control: Applying selective acaricides during the spring migration period when mites are exposed.
• Plant health: Maintaining vigorous plant growth through proper irrigation and fertilization.
• Monitoring: Regularly checking plants during the early growth phase for initial signs of gall formation.