Sand Topdressing Rate and Interval Effects on Anthracnose Severity of an Annual Bluegrass Putting Green
- John C. Inguagiato *a,
- James A. Murphyb and
- Bruce B. Clarkeb
Sand topdressing has been reputed to increase anthracnose caused by Colletotrichum cereale Manns sensu lato Crouch, Clarke, and Hillman on annual bluegrass (ABG) [Poa annua L. forma reptans (Hausskn.) T. Koyama] putting greens. Field trials were conducted to determine the effects of (i) frequent (7 d) and low-rate (0.3 L m−2) sand topdressing and brushing, (ii) infrequent (21 and 42 d) and increased-rate (1.2 L m−2) sand topdressing, and (iii) sand topdressing application intervals (7, 14, and 28 d) and rates (0.3 and 0.6 L m−2) on anthracnose severity of ABG turf mowed at 3.2 mm. Topdressing every 7 d at 0.3 L m−2 initially enhanced disease (8%) during the first year of the trial; however, continued topdressing reduced anthracnose severity 17 to 47% later in 2006 and 3 to 26% in 2007 compared to nontopdressed turf. Topdressing every 21 and 42 d at 1.2 L m−2 reduced disease 4 to 28% over the 2-yr study; however, sand applied every 21 d reduced disease 5 to 13% more than the 42-d interval in 2007. Topdressing rate (0, 0.3, and 0.6 L m−2) and interval (7, 14, and 28 d) interacted to affect anthracnose severity in both years. Disease declined in a curvilinear manner as rate increased at the 7- and 14-d intervals each year. Increased rates applied every 28 d reduced disease linearly in 2006 and curvilinearly at rates exceeding 0.3 L m−2 in 2007. Topdressing every 7 or 14 d at 0.3 or 0.6 L m−2, respectively, provided the most rapid and effective anthracnose reduction and best turf quality.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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