Effect of grower management practices on insect damage to sweetpotato roots
Nancy L. Brill, email@example.com, Jonathan R. Schultheis, Jonathan_Schultheis@ncsu.edu, David W. Monks, David_Monks@ncsu.edu, Kenneth A. Sorensen, Kenneth_Sorensen@ncsu.edu, Natalia Botero-Garcés, firstname.lastname@example.org, and George Kennedy, George_Kennedy@ncsu.edu. North Carolina State University, Department of Horticultural Science, Kilgore Hall, Raleigh, NC
North Carolina ranks first in the United States in sweetpotato (Ipomoea batatas Poir) production with 40,000 acres harvested annually. Beauregard is the principal variety produced, but despite its advantages, insect-caused damage results in significant economic loss each year. On-farm research was conducted in 2003 with five growers: at each grower’s field (replicate) an early and a late planting date, approximately 30 days apart, were compared. Roots were harvested approximately 90, 105, and 120 days after each of the planting dates and graded according to USDA standards, scoring them for amount and severity of damage caused by sweetpotato flea beetle (Chaetocnema confinis), WDS (wireworm/Diabrotica/Systena complex), grubs, and whitefringed beetle (Graphognathus spp.). Significant interactions between planting and harvest dates were found for damage caused by both flea beetle and WDS: damage increased (6% and 31%, respectively) when sweetpotatoes were established early and harvest time went up to 90-120 days. Sweetpotatoes established at the later planting date showed similar root damage (42% for flea beetle and 20% for WDS) regardless of the harvest time. Severity of damage (length of flea beetle lesions and diameter of WDS holes) increased with amount of injury. At the two locations it occurred, grub damage was affected only by planting date. Whitefringed beetle damage was not detected. The results of this on-going study suggest that growers need to consider early planting and a shorter growing season to reduce insect damage to sweetpotato roots.
Species 1: Coleoptera Chrysomelidae Chaetocnemaconfinis (sweetpotato flea beetle) Species 2: Coleoptera Chrysomelidae Diabroticaspp (cucumber beetle) Species 3: Coleoptera Chrysomelidae Systenaspp (flea beetle) Keywords: Ipomea batatas, wireworms