Soil silicon amendment for managing gray leaf spot of perennial ryegrass turf on golf courses in Pennsylvania

摘要

Gray leaf spot (Magnaporthe oryzae) of perennial ryegrass (Lolium perenne) is commonly managed by fungicide applications. With increasing public concerns over chemical usage and emergence of fungicide-resistant pathogen populations, the golf course industry seeks disease management through integrated management practices. Silicon (Si) amendments have been proven effective in controlling fungal diseases of various crops including turfgrasses. This study investigated the effects of Si applications on gray leaf spot development on perennial ryegrass turf on commercial golf courses. Silicon sources wollastonite and calcium silicate slag were applied at 0, 0.5, 1, 2, 5, and 10 t/ha at two golf courses in Pennsylvania with different soil types: an Ultisol and an Alfisol. The turf was inoculated with M. oryzae 10 weeks after silicon application, and disease development was monitored over a 10 week period. Results showed that area under the disease progress curve and final disease severity 10 weeks after inoculation were significantly reduced by Si applications at both sites. The magnitude of disease reduction was greater in the perennial ryegrass turf grown on the Ultisol. Tissue Si content increased with increasing rates of calcium silicate at both sites. Leaf tissue content of other macro-and micro-nutrients did not change when Si was applied at either site. Soil analysis showed that soil Si and pH increased with increasing rates of Si at both sites. These findings suggest that Si applications can reduce gray leaf spot development on perennial ryegrass turf on golf courses and may prove to be of use in the integrated management of turfgrass diseases.