Influence of calcium and nitrogen fertilizer on creeping bentgrass infected with dollar spot under cool temperatures

Abstract

AbstractDollar spot, caused by the fungal pathogen Clarireedia homoeocarpa Bennett, is a wide‐spread disease of creeping bentgrass (Agrostis stolonifera L.) that in the north central region of the U.S., occurs as early as March. Over‐dependence on fungicides has resulted in widespread resistance, necessitating non‐chemical treatment approaches. The objective of this experiment was to assess the effects of N and Ca fertilizers on creeping bentgrass for dollar spot tolerance under cool temperatures. In a chilling chamber, a single application of Ca or N fertilizer significantly reduced dollar spot disease cover by 47% or 34%, respectively, compared to the untreated control. Application of both Ca and N, however, appeared to be antagonistic and resulted in only a 14% reduction of disease cover. Application of Ca, not N, improved root production but reduced shoot growth in the 4‐week period regardless of dollar spot, resulting in an elevated root to shoot ratio. Root architecture, including total root length, surface area and total tips, was also improved following a Ca only application. Collectively, these results suggested that Ca might play a beneficial role in improving the stress tolerance of creeping bentgrass, and building healthier and stronger root systems in the spring‐like conditions. Although a single application of Ca does not adequately suppress dollar spot, future research might be of interest to explore optimal application strategies in order to reduce over‐dependence on fungicides.