Effects of seed treatment chemicals on stand establishment and yield obtained from billet planting in Louisiana

Billet planting has been problematic under subtropical conditions in Louisiana due to environmental stress and stalk rots. The seed treatment chemistry that is a component of the PleneTM sugarcane planting system developed by Syngenta AG is being evaluated for ability to increase billet planting yield. Machine-cut billets with three to four buds of three cultivars were dipped prior to planting in either a mixture of three fungicides (azoxystrobin, fludioxonil, and mefenoxam); an insecticide (thiamethoxam) with a nematicide (abamectin); a combination of fungicides, insecticide, and nematicide; or left untreated. In experiment one, plant cane tonnage was higher in the total pesticide combination treatment compared to non-treated billets for all three cultivars, and total sucrose yield was higher for two cultivars. Cane tonnage also was higher for the insecticide/nematicide treatment for one cultivar. Increased cane tonnage was associated with improved initial and spring stand establishment, higher millable stalk population and increased stalk weight. Cane tonnage and total sucrose yields were again higher for the total pesticide treatment compared to non-treated billets in first ratoon for one cultivar. In experiment two, the industry standard whole stalk planting was included for comparison. Initial and spring stands were increased, and tonnage was higher for the total pesticide treatment compared to the non-treated billet, insecticide/nematicide, and whole stalk treatments for one cultivar. Total sucrose was higher compared to non-treated billets and insecticide/nematicide treated billets for the same cultivar. Stalk population was higher for the total pesticide and whole stalk treatments compared to fungicide treated and non-treated billets for a second cultivar. The results suggest that application of the total mixture of fungicides, insecticide, and nematicide can improve yield obtained from plantings of billets with three to four buds and provide yield similar to whole stalk planting under Louisiana conditions.