Control of Wireworm on Sweet Potatoes, 1974

‘California’ sweet potato sprouts were planted on May 20‘74 in 3 row plots (32 inch row spacing) 40 feet in length. Plant population was approximately 14,000 plants/A. The treatments were arranged in a random-ized complete block design with 4 replications. The soil was a Norfolk “A” loamy sand. All granular materials were applied broadcast with a PCB spreader Model B. The spray treatments were applied with a CO2 sprayer (25 gal water/A at 40 psi). Preplant treatments were applied May 16 and were incorporated 3-5 inches into the soil with a single discing. Soil temperature at the 4 inch depth at the time of preplant application was 21°C. Post plant treatments were applied over the foliage Jul 24, when the roots began to enlarge. Yield data were taken from 3 sections of row, 30 feet in length. At harvest time, 100 roots/treatment/replication were selected at random and examined for wireworm injury.