Bacterial spot has been a threat to South Carolina peaches for as long as anyone can remember, but now, a Clemson University student is hoping his research can bring some relief to the peach industry. Brodie Cox, a master’s student in plant and environmental sciences from Aiken, is focusing his studies on bacterial spot caused by Xanthomonas arboricola pv. pruni.
Bacterial spot is a major disease in peaches. Symptoms on green fruit include water-soaked lesions, while symptoms on maturing fruit vary from light speckles to deep crater lesions. Leaves also are affected and show yellowing starting at the tip end. Severe leaf infections can cause early defoliation, resulting in reduced fruit size, sunburn and cracking.
According to Cox’s major professor, Clemson plant pathologist Guido Schnabel, the fight against bacterial spot is a constant battle: “Growers spray for this disease all of the time. But we still cannot effectively manage bacterial spot.”
The study focuses on determining where the bacteria overwinter and how they adapt to chemical exposure. Cox collected tissue samples from four South Carolina peach farms three times during the growing season — in early spring, late spring and two weeks before harvest in mid/late summer — to capture a picture of the bacteria’s sensitivity to chemicals throughout the growing season.
