Efficacy of spring fenarimol applications for spring dead spot control in a Tifway bermudagrass fairway in Mississippi
M. TOMASO-PETERSON (1)
(1) Mississippi State University, Mississippi State, MS, U.S.A.
Phytopathology 101:S177

Spring dead spot, caused by Ophiosphaerella korrae, is an annual disease of bermudagrasses that undergo dormancy. A study was conducted on a golf course with a Tifway bermudagrass fairway in West Point, MS to evaluate the effectiveness of spring fenarimol fungicide treatments and fertilizer for controlling this disease. Treatments served as the main plot factor and included fenarimol (spring, fall, spring followed by fall), propiconazole, myclobutanil, and azoxystrobin (all fall), and a check. Fertilizer nitrogen source (sub-plot factor) was applied as an organic or inorganic (ammonium sulfate) 12N-2P-12K at 0.5 N kg per 93 m². Spring dead spot severity and percent disease were visually assessed in April, 2009 and 2010. Turfgrass quality was rated monthly and spring green-up was recorded in March of both years. The fenarimol, spring only treatment, was equally effective, based on SDS severity, as fall treatments of fenarimol, propiconazole, myclobutanil, and azoxystrobin. The nitrogen source did not influence spring dead spot control. Turfgrass quality and spring green-up were similar for all treatments. An advantage of a spring fungicide application is that only areas where the disease is active and exhibiting SDS symptoms are treated. This allows the superintendent to make sight-specific fungicide applications on fairways that may in turn be more cost effective as well as provide an acceptable level of spring dead spot control.