Guardian Angel Protects Peach Trees

Guardian, a new peach tree rootstock, has begun helping growers battle the leading cause of peach tree death in the southeast. Peach tree short life (PTSL) costs growers about $10 million annually. It strikes in the spring, usually when the trees are 3 to 7 years old.

Horticulturist Thomas G. Beckman with the Agricultural Research Service co-developed the rootstock with Clemson University scientists. ARS is the chief research agency of the U.S. Department of Agriculture.

Guardian proved its value during its first field tests from 1989 to 1996 in South Carolina and Georgia. There, scientists planted trees on Guardian rootstock and compared them to trees grown on two commonly used commercial rootstocks, Lovell and Nemaguard. Lovell has tolerance to PTSL; Nemaguard resists root knot nematodes. Guardian has a unique combination of resistance to both problems.

The two-pronged protection paid off. By 1996, no Guardian trees were lost to PTSL in test orchards in South Carolina, and only 20 percent were lost in Georgia. By contrast, 97 percent of the Lovell trees in South Carolina died; 40 percent in Georgia. For Nemaguard, 95 percent of South Carolina's trees, and 80 percent of Georgia's, succumbed to the disease.

ARS and Clemson University have jointly applied for a plant variety protection certificate on Guardian rootstock, which is available only through licensed nurseries.

An in-depth article on this research appears in the October issue of Agricultural Research magazine. The story is also on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/oct98/guard1098.htm

Scientific contact: Thomas G. Beckman, ARS Southeast Fruit and Tree Nut Research Laboratory, Byron, Ga., phone (912) 956-6436, fax (912) 956-2929, a03tbeckman@attmail.com.