Sand Topdressing and Foot Traffic Effects On Anthracnose Severity of Annual Bluegrass Putting Green Turf.

Sand topdressing on putting greens can improve surface characteristics, which enhance aesthetics and playability of the turf.  Anthracnose is a disease of annual bluegrass [Poa annua L. f. reptans (Hausskn) T. Koyama], caused by Colletotrichum cereale Manns, that is more severe on stressed turf and was thought to be enhanced by sand topdressing particularly in combination with foot traffic.  A two year field study was initiated in 2007 to evaluate the effect of foot traffic and sand topdressing on anthracnose severity in North Brunswick, NJ.  A split-plot design with foot traffic [none and 392 footsteps m^-2 d^-1 (200 rounds d^-1)] as the main factor and sand topdressing (none and 0.3 L m^-2 wk^-1) as the subplot factor was used on annual bluegrass turf maintained as a putting green.  Traffic was applied as straight line passes 5 d wk^-1 by students wearing golf shoes equipped with soft spikes.  Anthracnose was rated regularly using a line-intersect grid counting method.  Foot traffic reduced anthracnose severity as much as 27%, regardless of sand topdressing during both years.  Additionally, traffic did not enhance anthracnose severity of sand topdressed turf.  While sand topdressing initially increased disease slightly in 2007, continued applications decreased disease by August 2007 and again in 2008.  The combination of foot traffic and sand topdressing resulted in the best turf quality by the end of both seasons.  Results indicate that the practice of topdressing should not be terminated when anthracnose develops on annual bluegrass putting greens.