Using nanocrystals as peach bud ‘baby blankets’

The Palmetto State is home to some of the best peaches in the southeastern United States.

But pleasing the palate is not the only role peaches play in South Carolina. The peach industry also is a major contributor to the state’s economy. To help keep the industry growing, the Clemson University Cooperative Extension Service Peach Team is researching how to keep pests at bay, as well as how using new technologies can help protect peaches.

During the annual Ridge Peach Producers Meeting in Edgefield, South Carolina, Peach Team members briefed growers on how to attack these pests. One discussion was what growers can do now that the insecticide chlorpyrifos has been banned for use on food crops. Brett Blaauw, professor and Extension specialist with the Clemson Cooperative Extension Service and the University of Georgia Extension Service, said changes in management practices can help growers compensate for the loss of this tool.

“Chlorpyrifos was commonly recommended for use as a tank mix with horticultural oil to apply in late winter for delayed dormant timing to manage San Jose scale and lesser peach tree borer,” Blaauw said. “During post-harvest, usually late summer, chlorpyrifos was commonly used as a trunk spray to provide more insect pest management. With the ban on chlorpyrifos, growers will need to replace those sprays with different chemicals or management tactics, such as mating disruption for borers.”

Chlorpyrifos is an inexpensive, but effective insecticide widely used in agriculture for more than 56 years. It is a broad-spectrum insecticide first registered for use in 1965 and kills insects by affecting the nervous system. The Environmental Protection Agency banned the use of chlorpyrifos on food and feed crops in August 2021. 

Alternative management tactics currently available are more expensive and potentially more difficult to implement than chlorpyrifos. Alternative insecticides cost more per acre, but the application methods should be the same as with chlorpyrifos. In addition, using cultural controls such as mating disruption and entomopathogenic nematodes (EPNs, which are beneficial nematodes) are both more expensive and potentially more difficult to implement in the field. Implementing controls such as mating disruption requires labor to hang pheromone dispensers in peach trees at a rate of 150 dispensers per acre.

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