SPARTANBURG — South Carolina is one of the top three peach-producing states and 2016 looks to be a great year for the sweet, succulent fruit.
Andy Rollins, a Clemson University Extension agent, said from what he has seen and what growers have told him, the peach crop looks “pretty good this year.” Rollins specializes in fruit and vegetable crops in the Upstate.
“We normally have a cooler fall than we had last year and we also had extremely wet weather this year,” Rollins said. “But despite all of that, we still were able to get in all of our chilling hours. This year could be one of the best years ever for our peach crop.”
Chilling hours are the number of hours peach trees have in temperatures below 45 dgrees. Peach trees drop their leaves in the fall and go into a developmental state known as a period of dormancy. As winter progresses, the trees enter another state known as rest. While in the rest stage, the trees cannot grow. Chilling temperatures are necessary for the trees to overcome the period of rest. Budbreak and normal growth occur after a peach tree has come out of its rest stage. Depending on the variety, peach trees in South Carolina require approximately 800 to 1,000 chill hours, Rollins said.
Peach Pest Control For Growers
While weather may not have created problems, San Jose scales have, Rollins said. San Jose scales are small insects that usually go unnoticed until the population injures the tree. The scales survive the winter as partially developed male and female adults. Development continues when the sap flow begins in the spring and they become fully developed about the time the peach trees are in bloom. This species does not lay eggs, but gives birth to crawlers that immediately disperse over the tree. There are four to six generations per year.
The insects suck plant juices and gradually hinder tree development. Scale is present at some level in every peach orchard. The adult stage is best controlled with oil applied while the trees are dormant. The crawler stage is best controlled after they have begun to hatch from their eggs.
When San Jose scales are detected, Rollins said to spray the trees with a dormant oil to smother the insect and that coverage is critical for control. Dormant oils can be applied before when the temperature is above 40 degrees. The oil sprays work by smothering the overwintering adult females. They offer the best control when applied during the dormant season. Growers should spray the trunk and limbs to the point of runoff and read label directions.
“San Jose scales literally suck the life out of peach trees,” Rollins said. “Dormant oils are environmentally friendly and very safe to use to control these pests. Some organic peach growers use these oils to protect their crops.”
Scales are almost always found on peach trees, making dealing with them more of a maintenance issue, Rollins said. Injury to peaches by scales is characterized by reddish/purple spots on the fruit.
“Even with the spots, the fruit is safe to eat,” Rollins said. “It’s ugly, but still safe to eat.”
It’s also nearing the end of pruning season, Rollins said. Pruning should be completed before the trees begin to bloom.
In addition to insects, peach growers also should be on the lookout for diseases. Brown rot and peach scab are two diseases of concern for peach growers.
“It is always critical that peach growers think about brown rot and peach scab,” said Guido Schnabel, Clemson plant pathologist. “These are the two main fruit diseases we deal with.”
For scab disease management, Schnabel advises applying targeted sprays after bloom. For effective brown rot management, pre-harvest fungicide applications are needed, he said.
To aid peach growers in integrated pest management, the Clemson Extension Service has a smartphone application, called My IPM. Created by Schnabel and Roy Pargas, a software designer, the Android version was released on Google Play in January 2015 and the iOS version hit the App Store in March 2015.
The app includes detailed information on around a dozen diseases and several abiotic disorders for each fruit, as well as tips on chemical and non-chemical disease management. It provides picture galleries that can be used to do in-field diagnostics and audios from regional experts, as well as interactive tables that can help growers design effective spray programs. In addition to information for peaches, the app also has strawberry-related information.
South Carolina produces the second largest peach crop in the United States. According to the United States Department of Agriculture National Agricultural Statistics Service, South Carolina produced 69,000 tons of peaches in 2015. California produced the most and Georgia came in as the third largest producer of peaches in 2015.
More information about growing peaches in South Carolina is on the Peaches and Nectarines fact sheet. Growers also can find information in the 2016 Southeastern Peach, Nectarine and Plum Pest Management and Culture Guide.
This story was written by Denise Attaway, Clemson University.