Gainesville Landscape Pest of the month: Holly scale

Have you noticed a black moldy coating on the leaves of your holly plant? This isn’t mold, it’s actually a symptom of our pest of the month. Holly Scale. Your hollies have an infestation of one of the many kinds of scale insects. Scale can’t digest all the sap they suck from leaves so they secrete honeydew, which allows sooty mold to grow on leaves. The honeydew accumulates on the foliage and can cause it to look shiny and feel sticky.

This rich food source does not go unnoticed. Ants, wasps and other insects may be attracted to the sweet honeydew. Even more common is the growth of fungal organisms that produce an unattractive black coating on the leaves called sooty mold. These fungi feed on the honeydew and do not attack or directly damage the plant, but the appearance of sooty mold is often the gardener’s first noticeable sign of trouble.

Light infestations of scale can be scraped off by hand or infested branches pruned out. Promptly dispose of prunings. For heavier infestations, spray with horticultural oil in the early spring to kill adults. An oil spray should be applied before new growth begins to kill both over-wintering adults and eggs.

For proper control, it is critical to apply the oil spray over every surface of the plant. If the insects are on the underside of the leaves and the oil is only applied to the upper surface, it will have no effect on them. Because scale insects are difficult to kill, one or two follow-up applications should be made after the first one. Follow label directions carefully.

If you come across a Gainesville lawn pest or Gainesville, Florida landscape pest, please don't hesitate to let us know if we can help. Contact our office at (352) 378-5296 and one of our technicians would be glad to assist you. We are a locally owned and operated lawn pest control service proudly located in Gainesville, Florida.