An Integrated Cultural Management Approach for Brown Patch Disease Suppression in Tall Fescue Lawns

Jada Sue Powlen, Purdue University

Abstract

Brown patch (caused by various Rhizoctonia and Rhizoctonia-like species) is one of the major summer diseases of tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.]. Fungicides are available to suppress brown patch; however, there is increasing interest to reduce lawn pesticide inputs. Excessive summer nitrogen (N) applications and extended periods of leaf wetness have been suggested to enhance brown patch. Five projects were conducted from 2020 to 2022 to evaluate individual and various combinations of cultural management practices to improve brown patch management strategies through reducing chemical inputs and promoting environmentally sound integrated pest management (IPM) practices. Brown patch host resistance of 15 tall fescue cultivars was evaluated in a controlled environment study and various morphological characteristics were correlated to brown patch severity. A 45% reduction in brown patch was observed with a resistant cultivar, and cultivars with faster growth rates, wider sheath widths and shorter sheath length correlated with reduced brown patch resistance. A field study evaluated five cultivars fertilized with urea-N from April to July, totaling 73.5 or 245.0 kg N ha-1 . A resistant cultivar had the greatest influence on reducing disease, and N-rate generally did not influence disease severity. Differences in seasonal brown patch was compared in a three-year field study for various natural organic fertilizers. Feather-bone meal and soybean meal-based products decreased disease compared to non-fertilized turf. Chemical suppression of leaf-wetness was studied using different surfactant chemistries applied on a 14 to 21-d application frequency and some chemistries reduced disease. When evaluating the various interactions of cultivar, N rate, and surfactant compared to a granular fungicide, the greatest impact was achieved when planting a resistant cultivar, reducing disease severity by 68%. Additionally, the combination of a resistant cultivar and application of a surfactant had the same seasonal brown patch compared to a susceptible cultivar with fungicide applications during year two of evaluation. In summary, these studies demonstrate significant reductions in brown patch can be achieved when utilizing the aforesaid best management practices which can substantially reduce the need for frequent lawn fungicides.

Degree

Ph.D.

Advisors

Bigelow, Purdue University.

Subject Area

Agricultural chemistry|Agronomy|Atmospheric sciences|Bioengineering|Chemistry|Genetics|Organic chemistry|Polymer chemistry|Soil sciences

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