Reducing Anthracnose on a Poa Annua Putting Green with Frequent Applications of a Soil Surfactant.

Anthracnose is a turfgrass disease caused by the pathogen Colletotrichum cereale and is particularly damaging to Poa annua putting greens. The objective of this research was to evaluate the effects of Revolution (alkyl terminated block copolymer) and hollow-tine aerification on the incidence of anthracnose on a P. annua putting green in Oregon. An eight-month field experiment was initiated in February 2015 with a second year of replication concluding in September 2016. The experimental location was a USGA sand-based P. annua putting green at the Oregon State University Lewis-Brown Horticulture Farm in Corvallis, OR. Experimental design was a randomized complete strip-plot design replicated four times. Individual plots were 1.5 m2 and the total experimental area was 96 m2. Factors included rate and frequency of soil surfactant applications (seven levels, and a control) and spring aerification (aerified 20 April, or not aerified). Surfactant treatments were applied using a CO2-pressured backpack sprayer with a carrier volume of 814 L ha-1 at 2.8 bars of pressure. Response variables included turf quality on a 1 to 9 scale and area under disease progress curve (ADUPC) calculated for the duration of the trial from February to September. In 2015, the aerification treatment was not significant for any of the dependent variables measured. A 19.10 L ha-1 rate of Revolution applied once or twice a week, and 4.78 L ha-1 applied once a week resulted in the lowest AUDPC in 2015. The 19.10 L ha-1 rate of Revolution applied twice a week resulted in the greatest turf quality at the peak of disease (8 Sep) in 2015. At the time of submission, data for the 2016 trial were still being collected.