229-21 Nitrogen Fertilization Programming Effects On Anthracnose Disease of Annual Bluegrass Putting Green Turf.



Tuesday, October 18, 2011: 2:15 PM
Henry Gonzalez Convention Center, Room 008A, River Level

Charles J. Schmid, James Murphy and Bruce Clarke, Plant Biology and Pathology, Rutgers University, New Brunswick, NJ
Nitrogen fertilization affects the development of anthracnose disease (caused by Colletotrichum cereale Manns) of annual bluegrass [Poa annua L. f. reptans (Hausskn) T. Koyama] putting green turf; however, a more comprehensive understanding of N management strategies is needed. The objectives of this 24 mo field study were i) to evaluate N rate effect of late- or early-season granular-N fertilization on anthracnose severity and ii) to determine whether granular-N fertilization altered the effect of frequent, low rate soluble-N fertilization during mid-season on anthracnose. The study, conducted on annual bluegrass turf maintained at 3.2 mm, was initiated autumn 2008 in North Brunswick, NJ. Treatments were arranged as a 2 x 3 x 4 factorial with three replications. The first factor was the season in which the majority (67%) of granular-N fertilization was applied: autumn and spring. The second factor was the annual N rate of granular fertilization: 73, 146 and 219 kg ha-1. The third factor was the frequency/rate of soluble-N fertilization during the summer; soluble-N treatments were sprayed at 4.6 kg ha-1 of N at the frequencies of 0, 1, 2 or 4 weeks from mid-May through August (16 weeks). Spring granular-N fertilization reduced disease severity compared to autumn on all but two rating dates during the study. The annual granular-N fertilization rate of 219 kg ha-1 had less disease (8 of 12 ratings) than plots that received lower rates. The interaction between season and granular-N rate (5 of 12 ratings) indicated that reduced disease severity due to spring N-fertilization compared to autumn was only evident at the annual granular-N rates of 146 and 219 kg ha-1. Summer soluble-N applied at 4.6 kg N ha-1 week-1 had the greatest reduction in anthracnose severity compared to less frequent soluble-N treatments (10 of 12 ratings).
See more from this Division: C05 Turfgrass Science
See more from this Session: Student Oral Competition: Weed Control & Diseases In Turfgrass