Anthracnose disease and annual bluegrass putting green performance affected by mowing practices and lightweight rolling
Anthracnose (Colletotrichum cereale Manns sensu lato Crouch, Clarke & Hillman) has been a devastating disease on annual bluegrass (ABG) [Poa annua L. f. reptans (Hausskn.) T. Koyama] putting green turf over the past 15 yr. The objectives of this 2-yr field trial on ABG were to evaluate the impact of mowing height (2.8, 3.2, and 3.6 mm), mowing frequency (seven and 14 times wk–1), lightweight rolling (none and every other day), and possible interactions of those factors on anthracnose severity and golf ball roll distance (BRD). Mowing height had the greatest effect on anthracnose. Mowing at 2.8 mm increased disease severity 3 to 21% compared with mowing at 3.6 mm, while 3.2 mm was intermediate to higher and lower heights. Mowing frequency had little effect on anthracnose, although mowing 14 times wk–1 occasionally reduced disease severity 1 to 14% compared with seven times wk–1. Rolling every other day also occasionally reduced disease severity 5 to 6% under moderate disease pressure. Mowing at 2.8 mm generally provided the greatest BRD. However, similar or greater BRDs were achieved at 3.2 and 3.6 mm, using combinations of increased mowing frequency and/or rolling compared with mowing at 2.8 mm seven times wk–1 without rolling. Thus, anthracnose severity on ABG greens can be reduced by raising the mowing height as little as 0.4 mm, and BRD (≥2.9–3.2 m) can be maintained by increasing mowing frequency and/or rolling without increasing disease severity.