CALS scientists take part in most comprehensive sweetpotato study ever
The Southern Sweetpotato IPM Project is bringing about big changes in growers’ and packers’ practices across the Southeast by giving them improved integrated pest management strategies.
Researchers identified sweetpotato pests in each state and determined that because pests differ by state, management practices should also. They also delivered new pest management recommendations that reduce the need for high-risk U.S. Food Quality Protection Act-targeted insecticides. And they determined ways to reduce damage that takes place on packing lines.
The five-year, four-state sweetpotato project was launched in 2003 with funding from Gerber Products Co. and the U.S. Department of Agriculture’s Cooperative State Research, Education and Extension Service Risk Avoidance Mitigation Program.
Housed at N.C. State University, the project also involves Auburn University, Louisiana State University and Mississippi State University. Disciplines involved are entomology, horticulture, plant pathology and weed science.
The four states represented in the project produce 80 percent of the sweetpotatoes in the United States. The project is particularly important to North Carolina because the state is the nation’s largest sweetpotato grower, producing about 40 percent of the country’s annual yield of 1.6 billion pounds. About 40,000 North Carolina acres are devoted to sweetpotatoes, and the crop is worth more than $85 million annually.
The sweetpotato is a still a relatively minor crop, and so “it’s difficult to get research dollars to work on it,” says Dr. Gerald Holmes, associate professor of plant pathology. “Consequently it receives relatively little attention.”
But this study changes all that.
The project was the most comprehensive study ever of the sweetpotato, and it is one of the largest on any vegetable, says Dr. George Kennedy, William Neal Reynolds Professor and head of the Department of Entomology at N.C. State.
He said the project was started because “growers throughout the Southeast were not able to adequately manage their insect and post-harvest problems with the technology they had.”
To come up with recommendations that would work in farm fields and on packing lines, researchers brought farmers and packers into the project from the beginning. The farmers and packers met with researchers at the outset to identify their most pressing problems, and more than 40 North Carolina farmers gave scientists access to their farms to conduct tests.
That involvement was a central feature of the project, Kennedy says. “The large number of growers and packers participating in our research is the heart of our project. Without their involvement, we wouldn’t have been able to develop tools that work under real, on-farm conditions.”
During the first year of the study, researchers found that pest problems varied across the region. Entomologists also learned more about the insect pests so they could develop effective management strategies.
In the area of plant pathology, the project took an in-depth look at postharvest decay and the things that affect it; made correlations between field conditions and post-harvest susceptibility to diseases; and characterized the relationship between wounding and decay, according to Holmes. Project participants also published an extension bulletin to document an in-depth survey of sweetpotato packing line practices. The project made recommendations for altering packing lines to reduce root injury and postharvest diseases.
The scientists also found out that spraying insecticide on sweetpotato plants’ leaves is not effective in reducing root damage in North Carolina. Farmers used to apply an average of 3.7 foliar insecticides. But, today, says Dr. Mark Abney, an assistant professor of entomology who coordinated the project, that trend has changed. “A big proportion of the cooperators went all the way, eliminating foliar sprays.”
In addition to Holmes, Abney and Kennedy, two other College of Agriculture and Life Sciences faculty members were involved in the Southern Sweetpotato IPM Project: Dr. Jonathan Schultheis, Extension leader in the Department of Horticultural Science; and Dr. David Monks, assistant director of the North Carolina Agricultural Research Service.
— Dee Shore
Researchers identified sweetpotato pests in each state and determined that because pests differ by state, management practices should also. They also delivered new pest management recommendations that reduce the need for high-risk U.S. Food Quality Protection Act-targeted insecticides. And they determined ways to reduce damage that takes place on packing lines.
The five-year, four-state sweetpotato project was launched in 2003 with funding from Gerber Products Co. and the U.S. Department of Agriculture’s Cooperative State Research, Education and Extension Service Risk Avoidance Mitigation Program.
The four states represented in the project produce 80 percent of the sweetpotatoes in the United States. The project is particularly important to North Carolina because the state is the nation’s largest sweetpotato grower, producing about 40 percent of the country’s annual yield of 1.6 billion pounds. About 40,000 North Carolina acres are devoted to sweetpotatoes, and the crop is worth more than $85 million annually.
The sweetpotato is a still a relatively minor crop, and so “it’s difficult to get research dollars to work on it,” says Dr. Gerald Holmes, associate professor of plant pathology. “Consequently it receives relatively little attention.”
But this study changes all that.
The project was the most comprehensive study ever of the sweetpotato, and it is one of the largest on any vegetable, says Dr. George Kennedy, William Neal Reynolds Professor and head of the Department of Entomology at N.C. State.
He said the project was started because “growers throughout the Southeast were not able to adequately manage their insect and post-harvest problems with the technology they had.”
To come up with recommendations that would work in farm fields and on packing lines, researchers brought farmers and packers into the project from the beginning. The farmers and packers met with researchers at the outset to identify their most pressing problems, and more than 40 North Carolina farmers gave scientists access to their farms to conduct tests.
That involvement was a central feature of the project, Kennedy says. “The large number of growers and packers participating in our research is the heart of our project. Without their involvement, we wouldn’t have been able to develop tools that work under real, on-farm conditions.”
During the first year of the study, researchers found that pest problems varied across the region. Entomologists also learned more about the insect pests so they could develop effective management strategies.
In the area of plant pathology, the project took an in-depth look at postharvest decay and the things that affect it; made correlations between field conditions and post-harvest susceptibility to diseases; and characterized the relationship between wounding and decay, according to Holmes. Project participants also published an extension bulletin to document an in-depth survey of sweetpotato packing line practices. The project made recommendations for altering packing lines to reduce root injury and postharvest diseases.
The scientists also found out that spraying insecticide on sweetpotato plants’ leaves is not effective in reducing root damage in North Carolina. Farmers used to apply an average of 3.7 foliar insecticides. But, today, says Dr. Mark Abney, an assistant professor of entomology who coordinated the project, that trend has changed. “A big proportion of the cooperators went all the way, eliminating foliar sprays.”
In addition to Holmes, Abney and Kennedy, two other College of Agriculture and Life Sciences faculty members were involved in the Southern Sweetpotato IPM Project: Dr. Jonathan Schultheis, Extension leader in the Department of Horticultural Science; and Dr. David Monks, assistant director of the North Carolina Agricultural Research Service.
— Dee Shore