The Impact of Disease Suppressing and Plant Health Promoting Products on Creeping Bentgrass Grown Under Shade Stress.

Numerous products are available to turfgrass managers with both scientifically proven benefits and unsubstantiated claims of elevating endogenous plant response to environmental stresses. Researchers have proven that density of creeping bentgrass (CBG) declines after prolonged exposure to low light environments, but there is limited information available on whether certain plant health promotors (PHP) impact this decline from shade stress. Research studies were conducted to address the role of five PHP on ‘L-93’ CBG fairways exposed to low light intensities at the Virginia Tech Glade Road Research Center in Blacksburg, VA in 2015 and 2016. Treatments of fluxapyroxad 0.25 kg ai ha^-1 + pyraclostrobin 0.50 kg ai ha^-1 (Lexicon), aluminum tris 9.74 kg ai ha^-1 (Chipco Signature), chlorothalonil 8.12 kg ai ha^-1 + acibenzolar-s-methyl 0.016 kg ai ha^-1 (Daconil Action), azoxystrobin 0.61 kg ai ha^-1 + acibenzolar-S-methyl 0.014 kg ai ha^-1 (Heritage Action), and a proprietary phthalocyanine pigment 3.60 L ha^-1 (Foursome) were applied every 21 days, covered with a temporary shade structure until substantial turf decline occurred in most plots, with foliar diseases controlled throughout the season with fluazinam, iprodione, and propamocarb. Visual estimations of turf density and overall quality, plus spectral reflectance were positively impacted by Lexicon, Daconil Action, and Heritage Action, as CBG was exposed to prolonged shade stress. Foursome and Chipco Signature did not improve CBG density or quality, compared with the nontreated control. These data suggest that certain quinone outside inhibitor combinations and acibenzolar-S-methyl improve CBG tolerance to low light conditions. Conclusions of this research may be useful when selecting proper fungicides for controlling diseases in areas of low light intensity.