Microdochium patch is an important turfgrass disease in cool‐humid regions and is caused by the pathogen Microdochium nivale (Fries) Samuels & Hallett. Control of the pathogen is necessary to provide acceptable putting‐green‐quality turf, and fungicide applications are the predominant method of control. Increasing pesticide restrictions have generated interest in alternative management techniques of Microdochium patch. This research evaluated the effects of three nitrogen and five iron sulfate rates on Microdochium patch development on a trafficked, sand‐based, annual bluegrass (Poa annua L.) putting green in Corvallis, OR for over 2 yr in the absence of fungicides. Data included turf quality, area under disease progress curve, and soil test results of saturated paste extract pH, cation extractable sulfate, and DTPA‐sorbitol extractable iron. This research provided evidence that low rates of urea (4.88 kg N ha−1) applied every 2 wk did not lead to an increase in Microdochium patch severity and that iron sulfate applications decreased Microdochium patch on annual bluegrass putting greens. Despite the disease suppression observed, no treatment received a turf‐quality rating considered acceptable. Low turf‐quality ratings where disease development was low were attributed to turfgrass thinning or blackening of the shoots resulting from iron sulfate applications. Soil tests provided evidence that the highest iron sulfate level used in this study (97.65 kg ha−1) applied every 2 wk would likely lead to a lower soil pH and an increase in soil sulfate levels.

Microdochium patch is a turfgrass disease that occurs in cool, humid regions caused by the fungal pathogen Microdochium nivale (Fr.) Samuels & Hallett [Teleomorph = Monographella nivalis (Schaffnit) E. Müll]. Fungicide applications are the predominant method of control; however, pesticide restrictions have generated concern regarding the use of traditional chemicals to manage turfgrass pests. The objective of this research was to evaluate the effects of the cultural practice of rolling in combination with applications of mineral oil, S, and/or phosphorous acid (H 3 PO 3) on the suppression of Microdochium patch on an annual bluegrass (Poa annua L.) putting green. A 2-yr field trial took place from September 2013 to June 2014 and was repeated from September 2014 to June 2015 on a sand-based annual bluegrass putting green in Corvallis, OR. Experimental design was a 2 × 4 × 2 × 2 randomized complete split-plot design with four replications. Factors included rolling, the fertility products S and H 3 PO 3 applied alone and in combination, mineral oil treatment, and year. Mineral oil suppressed Microdochium patch although applications led to turfgrass thinning. The combination of S and H 3 PO 3 provided greater Microdochium patch disease suppression compared to applying either alone. Rolling also suppressed Microdochium patch in the second year of this study. Further research to determine how to best utilize these combined cultural practices to manage Microdochium patch is warranted. Abbreviations: AUDPC, area under disease progress curve. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Irrigation applied at a rate of 3.0 inches per month (0.75 inches per week) from July to September will provide improved perennial ryegrass turf quality and percent green cover in western Oregon.• Replacing 45 to 49% evapotranspiration is adequate to maintain acceptable turfgrass quality in this environmental zone.• Three inches of irrigation per month (0.75 inches per week) will provided perennial ryegrass turf quality and percent green cover equivalent to great irrigation amounts.• Eight irrigation applications per month (twice a week) will result in acceptable perennial ryegrass turf quality during the summer months while 16 applications per month (four time a week) will provide the greatest perennial ryegrass turf quality.Oregon State Univ., 4147 ALS Building, Corvallis, OR. *Corresponding author (alec.kowalewski@oregonstate.edu).

Microdochium patch is a turfgrass disease caused by the fungal pathogen Microdochium nivale (Fries) Samuels & I.C. Hallett that occurs most commonly in cool-humid regions such as the Pacific Northwest. Fungicide applications are the predominant method of controlling this disease, although alternatives to fungicides are desired in areas where pesticide restrictions occur. Previous research has shown that 97.6 kg FeSO 4 ⋅7H 2 O ha −1 applied every 2 wk in 814 L ha −1 water carrier suppresses Microdochium patch; however, turfgrass thinning occurred. The objective of this trial was to determine if higher water carrier volumes would mitigate turfgrass thinning while still suppressing Microdochium patch. This field trial quantified the effects of four different water carrier volumes of 97.6 kg FeSO 4 ⋅7H 2 O ha −1 applied every 2 wk on the suppression of Microdochium patch, percent green cover, and turfgrass quality of an annual bluegrass putting green in Western Oregon. This research demonstrated that 97.6 kg FeSO 4 ⋅7H 2 O ha −1 applied every 2 wk suppressed Microdochium patch on annual bluegrass putting greens to equivalent levels regardless of water carrier volumes ranging from 1019 to 4075 L ha −1. Higher percent green cover was also observed when higher water carrier volumes (3056 or 4075 L ha −1) were used. While iron sulfate heptahydrate treatments suppressed Microdochium patch to less than one percent disease throughout the trial, no water carrier volume reduced annual bluegrass thinning enough to be considered acceptable for golf course putting greens. Abbreviations: AUDPC, area under disease progress curve. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Core Ideas Increasing sulfur application rates reduced the number of fungicide applications required to manage Microdochium patch. Increasing sulfur application rates increased anthracnose severity. Calcium carbonate, calcium sulfate, and calcium phosphate did not have an effect on Microdochium patch or anthracnose severity.