Role of drought stress in the development of summer patch in field-inoculated Kentucky bluegrass
1990
Kackley, K.E. | Grybauskas, A.P. | Dernoeden, P.H. | Hill, R.L.
Field plots of Kentucky bluegrass (Poa pratensis) at two sites were treated with either live or killed inoculum of Magnaporthe poae (isolate ATCC 60239) and subjected to either a non-drought-stress (> -0.05 MPa) or drought-stress (< -0.05 MPa) treatment. Studies at site I were conducted on 1- and 2-yr-old stands of either the cultivar Aspen (resistant) or S-21 (susceptible). At site II, studies were conducted for one season on a 6-yr-old blend seeded as equal parts of Merion, Vantage, and Sydsport. Disease developed in the first year at both sites only in those plots receiving live inoculum. Disease was more severe in non-drought-stressed plots. There was no significant difference in disease development between cultivars at site I. In the second year at site I, disease developed where both live and killed inoculum had been placed. There was no significant difference in disease severity between stress treatments; however, there was consistently more disease in non-drought-stressed plots. Aspen was injured less than S-21 in the second year. Summer patch was more severe when soil water potentials were high, and drought stress was not a key predisposing factor in the development of this disease.
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