Evaluation of a Petroleum‐Derived Spray Oil for Control of Microdochium Patch and Turfgrass Spring Performance on Nordic Golf Greens

Abstract

Core Ideas Mineral oil was as effective as or more effective than fungicides in controling Microdochium patch. Repeated applications of mineral oil in autumn might inhibit turfgrass green‐up in spring. Mineral oil can reduce conventional fungicide use on Nordic golf courses. Greenkeepers are looking for alternatives to fungicides for control of turfgrass diseases. Our objective was to evaluate a petroleum‐derived spray oil with a blue‐green pigment for control of Microdochium patch/pink snow mold (Microdochium nivale) on golf course putting greens with various durations of snow cover. The spray oil was applied at rates 27 or 54 L ha−1 every third week from late August or September to December, either alone, in tank mixture with potassium phosphite (3 kg PO3 ha−1) or in tank mixture with half rate of fungicides approved for turf, in five 1‐yr trials in the Nordic countries. The oil was as effective or more effective than fungicides and gave, on average, 94 and 98% disease control at rates 27 and 54 L ha−1, respectively. Tank mixtures with half rate of prochloraz + propioconazole and fludioxonil did not increase disease suppression in a trial with 79 d snow cover. Phosphite reduced disease severity in one trial only and did not improve disease control or turfgrass quality when tank‐mixed with the oil. The pigment in the spray oil was highly persistent and improved turfgrass greenness except in a trial where the combination of oil and ice cover gave a transitory black color at ice melt. Another trial with long snow cover showed a drop in turfgrass quality in spring as the spray oil prevented normal green‐up. In conclusion, this research shows that a spray oil has the potential to reduce fungicide use on Nordic golf courses.

Controlling Snow Molds with CIVITAS TURF DEFENSE in Utah

“…The length of snow cover is impossible to predict each year, so using traditional fungicides is fundamental to a snow mold program in northern climates. However, including Civitas with other fungicides has had positive effects on spring quality when snow melts (Aamlid et al, 2018; Van Dyke and Johnson, 2017).…”

“…Maybe the longer snow cover contributed to greater virulence from the speckled snow mold pathogen and overwhelmed the plant defense. Civitas has not fared well in Wisconsin on Typhula snow molds (Koch, 2016a) or Microdochium patch/pink snow mold (Koch, 2016b) under lengthy snow cover, but has provided good suppression of pink snow mold where snow persists on Nordic golf courses (Aamlid et al, 2018). Earlier work from Utah showed Civitas has activity on snow molds (Van Dyke and Johnson, 2017) but applications were made all season, and efficacy was still influenced by disease severity as it related to snow cover between years.…”

Suppression of Microdochium patch using rotations of mineral oil, sulfur, and phosphorous acid

“…The only published research to date focused on using a tank mixture of mineral oil with H 3 PO 3 to suppress Microdochium patch in the absence of snow cover took place in Scandinavia (Aamlid et al., 2018) and western Oregon (Mattox et al., 2020). Therefore, limited information is available regarding the efficacy of different application intervals.…”

“…Thus far, no study has focused on seasonal rotations of these products. In the Scandinavian study, 19.9 and 39.8 kg (27 and 54 L) mineral oil ha −1 was applied with 3 kg H 3 PO 3 ha −1 every 3 wk suppressing Microdochium patch by 94 and 98%, respectively (Aamlid et al., 2018). In western Oregon, 19.9 kg mineral oil ha −1 applied with 3.7 kg H 3 PO 3 ha −1 every 2 wk suppressed Microdochium patch although unacceptable turfgrass thinning occurred (Mattox et al., 2020).…”

Evaluating biological and oil‐based fungicides for dollar spot suppression on turfgrass

“…Despite their promise and prevalence, use of biological and oil‐based products remains limited. The primary reason for their limited use is their poor and/or inconsistent level of disease control, which is often unacceptable for commercial turfgrass management (Aamlid et al., 2018; Goodman & Burpee, 1991; Nelson & Craft, 1991; Popko et al., 2010). One of the most commonly used and respected analyses of turfgrass fungicides is the Chemical Control of Turfgrass Diseases (Clarke et al., 2020).…”