Fungicide Seed Treatment Improves Performance of Single-Drop Whole and Cut Seed Potatoes

Seed potatoes in North America are predominantly cut and treated with a fungicide seed potato treatment before planting. Though seed potatoes that have been cut and fungicide-treated have been shown to perform as well or better than single drop seed (whole tubers in the range of 43–85 g) without fungicide seed treatment, no comparisons were made with single-drop seed that had been treated with a fungicide seed treatment. Here we present results from field experiments conducted in Bingham County, Idaho over ten consecutive years (2008–2017) using potato cultivar ‘Russet Burbank’ where both cut and single drop seed were first inoculated with isolates of Fusarium spp. and then treated with a fungicide seed treatment containing both fludioxonil and mancozeb. Single-drop seed outperformed cut seed with respect to emergence, vigor, and Fusarium seed decay, yield of large tubers, and total yield. However, the fungicide seed treatment offered a larger measure of improvement in terms of Fusarium seed decay and Rhizoctonia stem canker. The boost in yield of US No. 1 grade tubers for single drop seed (1.09 t/ha) was smaller than the increase due to an application of a commercial formulation of a mancozeb plus fludioxonil fungicide seed potato treatment (2.34 t/ha). Thus, the most important factor to consider, regardless of seed type, is use of a fungicide seed treatment.