Joshua Dake

San Diego, CA — Miramar Wholesale Nurseries are taking preventive measures at keeping Pierce’s disease at bay by containing the glassy-winged sharpshooter. The glassy-winged sharpshooter, which preys on at least 100 types of plants, have spread rapidly from Ventura to the Mexican border, and were found in the San Joaquin Valley.

The glassy-winged sharpshooter is an insect, which, by itself, has little effect on most plants. Instead, it is the bacterium the sharpshooter carries, Xylella fastidiosa, which does the damage. The bacterium is known to cause Pierce’s disease on grapevines, oleander leaf scorch, almond leaf scorch, citrus variegated chlorosis, and alfalfa dwarf. This bacterium attacks the plant tissue responsible for transporting water from the roots to the rest of the plant, known as the xylem. Once this tissue is infected, the plant becomes unable to uptake the water and nutrients it needs to survive.

Miramar Wholesale Nurseries feels that education and a strong prevention program is the best defense against this pest. Many of the employees have attended meetings to become well informed on the habits and hosts of the glassy-winged sharpshooter to provide assistance to their customers in protecting their landscapes against this disease. Also, the current pest prevention program guarantees that all stock purchased at Miramar Wholesale Nurseries is pest-free.

Pierce’s disease is not new. It has occurred periodically since the 1880’s when it destroyed 40,000 acres of grapes in the Los Angeles Basin. It currently threatens California’s $2.8 billion wine, table and raisin grape growing industry. A new outbreak has destroyed several hundred acres of vines in the Temecula Viticultural Area of Riverside County. There is no known cure for Pierce’s disease.

The glassy-winged sharpshooter is a native insect of the Southeastern United States, ranging from Florida to Eastern Texas, and as far as Kentucky to the north. This dangerous pest, thought to have been introduced to this region in the late 1980’s, probably entered as eggs on an incoming plant and has since become a nuisance to commercial growers and local gardeners throughout Southern California.

University of California scientists are researching methods of preventing and eliminating the bacterium. Professor Bruce Kirkpatrick of University of California, Davis is performing experiments on grapevines to test whether raising the levels of micronutrients such as zinc, magnesium, and iron in the plant can be effective in preventing infection. Professor Alexander Purcell of University of California, Berkeley is testing the effects of heavy pruning of plants during the winter months as a way of eliminating the bacterium and says that his early results have been promising. However, Purcell is still collecting data on how plant type and age will affect the success of pruning.

Miramar Wholesale Nurseries is Southern California’s leading supplier of landscape plant material and supplies. Miramar Wholesale Nurseries grows a wide-variety of perennials, shrubs, and trees at each of their three locations for future projects in and around the region. Their fully stocked will-call facilities in San Diego, Irvine/Lake Forest, and San Juan Capistrano serve the immediate needs of commercial properties, institutions, property managers, and commercial landscapers. In an acquisition in early 1999, Miramar Wholesale Nurseries became a member of the San Diego region of TruGreen-LandCare, a ServiceMaster company.

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