Control of Root Maggots on Turnip, in 1977 and 1978

Purple Top White Globe turnips were planted in 5- by 20-ft row beds with 22-inch interrow and 4 to 6-inch interplant spacing on Jul 26 '77 and Jul 27 '78, at Yakima, WA. The treatments were arranged in a randomized complete block with 4 replicates. The at-planting granular treatments of Dasanit were applied and incorporated, by using the “bow wave” method whereby the opening and covering shoes of the seeder are used to distribute and incorporate the insecticide. These were followed by the 30-day postplanting (= 40-day preharvest) application of a band spray of the SC formulation to the soil surface applied in 3.5 gal water/1000 lineal ft of row through “TEEJET” 8005 even spray flat fan nozzles operated at 60 psi by air pressure. Both methods resulted in 6-inch wide bands of insecticide over the row. The efficacy of the treatments was determined by removing, washing, and examining the roots of 15 plants selected at random from each bed at harvest. The number of plants injured and the degree of inury were noted and recorded.