Suppression of Microdochium nivale by potassium phosphite in cool-season turfgrasses

Abstract

Microdochium nivale (Fr.) Samuels and Hallett (teleomorph Monographella nivalis (Schafnitt) is one of the most damaging pathogens of cool-season amenity turfgrasses. The search for new or improved means to reduce susceptibility to M. nivale is an ongoing target for turfgrass research. From 2010 to 2012, field studies were conducted at the Curragh Golf Club, Co Kildare, Ireland on Agrostis canina L. ssp. canina and Poa annua L. swards, to evaluate M. nivale suppression by 14-day sequential applications of potassium phosphite (KH2PO3), applied alone and in combinations with a fungicide (iprodione) and a biostimulant. Treatment effect on turfgrass quality was also determined. Over two years of trials, phosphite treated plots, when compared with untreated controls, exhibited significantly lower percentages (p<0.01) of M. nivale incidence. The addition of the biostimulant did not enhance this effect. The iprodione treatments showed significantly higher suppression than the phosphite treatments (p<0.01), and the addition of phosphite significantly enhanced the fungicide control of M. nivale (p<0.01). This last combined treatment was most effective overall, with full inhibition on the treated plots. Turfgrass quality on all phosphite treated plots was significantly better (p<0.01) than either the control or iprodione treated plots. © 2012 Copyright Taylor and Francis Group, LLC.