Let me introduce you to one of the new pests to San Diego gardens, the Ficus Eye Spot Midge.
This gall-forming midge so far only attacks leaves of the Indian Laurel Ficus (Ficus microphylla or F. microphylla ‘Nitida’). In other parts of the world this gall midge has been found on other species of Ficus too. Locally the eye spot midge was first spotted in 2014 where it was initially prevalent in La Jolla and in Rancho Santa Fe. Eye spot midge damage on Indian Laurels is now county wide.
The young larvae of the eye spot midge make a gall inside leaf tissue that provides a home and food for the developing larva. When mature, the adults fly out an exit hole in the gall. The abandoned galls end up looking like sunken black spots that can resemble a bacterial or fungal disease.
Spinosad (packaged as Captain Jack’s Dead Bug), is an organic control for chewing insects like the citrus leaf miner. I have had some positive reports from clients using Spinosad to control the eye spot midge. Unfortunately, galls make leaf tissue tougher and more resistant to spray controls like Spinosad. Furthermore, large Indian Laurel hedges are not the easiest plants to completely cover with spray, especially when located on property lines where overspray can affect neighbors.
Tree and shrub systemic controls are available. Remember that systemic controls make the plant toxic to all critters, and should not be used near fruit trees or vegetable / herb gardens.
Apply control rights as new growth begins or right after pruning, which stimulates new growth. Unfortunately, you do not see the “black spot” damage until after the adult midge has flown away and is no longer present. Fortunately, damaged leaves will likely fall off within a year or so.