The effects of iron sulfate heptahydrate water carrier volumes on Microdochium patch suppression and turfgrass quality

Abstract

AbstractMicrodochium 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 FeSO4·7H2O 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 FeSO4·7H2O 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 FeSO4·7H2O 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.