University of Massachusetts Amherst ScholarWorks@UMass Amherst Masters Theses 1911 - February 2014 1998 The environmental fate of fungicides used to manage Magnaporthe poae, the causal agent of summer patch / Jeffery J. Doherty University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/theses Doherty, Jeffery J., "The environmental fate of fungicides used to manage Magnaporthe poae, the causal agent of summer patch /" (1998). Masters Theses 1911 - February 2014. 3468. Retrieved from https://scholarworks.umass.edu/theses/3468 This thesis is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Masters Theses 1911 - February 2014 by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. THE ENVIRONMENTAL FATE OF FUNGICIDES USED TO MANAGE MAGNAPORTHE POAE, THE CAUSAL AGENT OF SUMMER PATCH A Thesis Presented by JEFFERY J. DOHERTY Submitted to the Graduate School of the University of Massachusetts Amherst in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1998 Department of Plant Pathology THE ENVIRONMENTAL FATE OF FUNGICIDES USED TO MANAGE MAGNAPORTHE POAE, THE CAUSAL AGENT OF SUMMER PATCH A Thesis Presented by JEFFERY J. DOHERTY Approved as to style and content by: Gail L. Schumann, Chair Mark S. Mount, Member oJ* John M. Clark, Member Bruce B. Clarke, Member Mark S. Mount, Department Head Plant Pathology ACKNOWLEDGMENTS A Masters thesis is actually the end product of the work of many people. I would like to thank Michael Johnson, Dwight Jesseman, Bess Dicklow, Lori Bickford, Tania Fernandez and Sharon Sousa for assisting me in the laborious task of preparing samples. The personnel at the Massachusetts Pesticide Analysis Laboratory - Dan, Ray, Gerry, Laura and Andy - provided invaluable technical assistance (and put up with my inveterate whining). I am indebted to the members of my committee - Dr. Schumann, Dr. Clark, Dr. Mount and Dr. Clarke - for their advice and feedback. The Umass Turfgrass Research Facility and the Massachusetts Pesticide Analysis Lab provided facilities without which this project could not have been accomplished. Research funding and support of my graduate education is gratefully acknowledged to the following organizations: Golf Course Superintendents Association of New England Inc., Massachusetts Turf and Lawngrass Council Inc., Ciba-Geigy Corporation (now Novartis), DowElanco (now Dow Agrosciences), E.I. duPont de Nemours and Co., and Mobay Corporation (now Bayer Corporation). I owe a special debt of gratitude to my adviser. Dr. Gail Schumann, who saw in me some potential and gave me a chance. For this and her support throughout this process I am very grateful. Special thanks go out to Dr. J.M. Clark, without whose advice and encouragement I never would have survived this arduous process. Ill ABSTRACT THE ENVIRONMENTAL FATE OF FUNGICIDES USED TO MANAGE MAGNAPORTHE POAE, THE CAUSAL AGENT OF SUMMER PATCH MAY 1998 JEFFERY J. DOHERTY, B.S., UNIVERSITY OF MASSACHUSETTS AMHERST M.S. UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Gail Schumann Magnaporthe poae , an ectotrophic, root-infecting fungus, is the causal agent of summer patch, a very damaging disease of Poa and Festuca species. Chemical control of summer patch is both erratic and expensive, suggesting a difficulty in delivering the fungicides to the root zone. The most important barrier to efficacious delivery of the fungicides to the roots is the thatch layer, a tightly intermingled layer of living and dead stems, leaves, and roots of grass that develops between the verdure and the soil surface. Three different application technologies, a boom sprayer, a high pressure injector, and a modified slicer/seeder, were compared to determine if any were superior in delivering the fungicides fenarimol, propiconazole, and triadimefon to the root zone without increasing the possibility of groundwater contamination. Four different matrices of the turfgrass system, leaf, thatch, soil, and roots, were analyzed for the presence of the fungicides. None of the application methods allowed any of the three fungicides to reach the roots in any appreciable amount, principally due to their high affinity for the thatch. Regardless of application type, the majority of the fungicides (40-80%) were found associated with the thatch layer. IV Additionally, none of the fungicides were ever found below the top 5.1 cm of the soil, so the threat of groundwater contamination appears minimal over the time course of this experiment (1 month). Triadimefon is rapidly hydrolyzed to triadimenol in turfgrass plants, thatch, soil, and roots. Triadimenol poses a greater threat to groundwater than triadimefon because it is more water soluble, has a greater half-life, a lower organic carbon/water partition coefficient and greater mammalian toxicity than triadimefon. Triadimefon was rapidly converted to triadimenol in all four matrices, and was not detectable at the end of the experiment (28 days). Triadimenol was the only compound detected in the roots in any appreciable amount ( 0.04 - 0.19% of the applied triadimefon). However, triadimenol was never detected below the top 5.1 cm of the soil profile, so its threat to groundwater over the course of the experiment appears minimal. Benomyl was applied to determine if post-application irrigation had any effect on its delivery to the root zone. Post-application irrigation appeared to allow benomyl to move into the thatch and roots more quickly. Immediately after application, benomyl residues in the root tissue of the irrigated plot were 2.2 times greater than those found in the non- irrigated plot. By the end of the experiment (14 days), however, there was no difference between the irrigated and the non-irrigated plots. Because a large proportion of the applied fenarimol, propiconazole, and the triadimefon metabolite triadimenol remained associated with the thatch at the end of the study, a longer experimental time frame should be examined that includes spring and fall recharge events in future research. TABLE OF CONTENTS Page ACKNOWLEDGMENTS.iii ABSTRACT.iv LIST OF TABLES.x LIST OF FIGURES.xi Chapter 1. INTRODUCTION AND LITERATURE REVIEW.I 1.1 Ecology and Epidemiology of Magnaporthe poae.2 1.2 Environmental Effects on Summer Patch Development.6 1.3 Management of Summer Patch.8 1.4 Sterol-Biosynthesis Inhibiting Fungicides.12 1.4.1 Mode of Action of Sterol-Biosynthesis Inhibiting Fungicides. 12 1.4.2 Classes of Sterol-Biosynthesis Inhibiting Fungicides.13 1.4.2.1 Azoles.13 1.4.2.2 Pyrimidines.15 1.5 Benzimidazole Fungicides.15 1.5.1 Benomyl Mode of Action. 16 1.6 Environmental Fate of Fungicides Applied to Manage Patch Diseases. 18 1.6.1 Drift. 19 1.6.2 Photochemical Degradation. 19 1.6.3 Volatility. 22 1.6.4 Runoff.. 24 1.6.5 Plant Uptake. 25 1.6.6 Thatch Layer. 29 1.6.7 Degradation. 33 1.6.8 Mobility. 36 VI 2. ENVIRONMENTAL FATE OF FENARIMOL, PROPICONAZOLE, AND TRIADIMEFON APPLIED TO KENTUCKY BLUEGRASS UTILIZING THREE APPLICATION SCHEMES.41 2.1 Introduction. 41 2.2 Materials and Methods.47 2.2.1 Experimental Site. 47 2.2.2 Fungicides. 47 2.2.3 Fungicide Application. 47 2.2.4 Sampling. 50 2.2.5 Storage Samples. 52 2.2.6 Analytical Procedures. 52 2.2.7 Instrumental Analysis. 54 2.2.8 Quality Assurance/Quality Control. 55 2.2.8.1 Instrument Calibration.55 2.2.8.2 Sample Controls.55 2.3 Results. 57 2.3.1 Fungicide Concentration. 57 2.3.1.1 Leaf Tissue. 57 2.3.1.2 Thatch. 61 2.3.1.3 Soil. 65 2.3.1.4 Root Tissue. 69 2.3.2 Total Accumulated Residue. 72 2.3.2.1 Leaf Tissue. 72 2.3.2.2 Thatch. 72 2.3.2.3 Soil. 72 2.3.2.4 Root Tissue. 74 2.3.3 Percent of Applied Fungicide Recovered. 74 2.3.3.1 Leaf Tissue...,. 74 2.3.3.2 Thatch. 82 2.3.3.3 Soil. 84 2.3.3.4 Root Tissue. 85 2.4 Discussion. 86 Vll 3. FATE OF TRIADIMEFON AND TRIADIMENOL IN A TURFGRASS SYSTEM.93 3.1 Introduction. 93 3.2 Materials and Methods.94 3.2.1 Experimental Site. 94 3.2.2 Fungicides. 96 3.2.3 Fungicide Application. 96 3.2.4 Sampling. 97 3.2.5 Storage Samples. 98 3.2.6 Analytical Procedures. 98 3.2.7 Instrumental Analysis. 100 3.2.8 Quality Assurance/Quality Control. 101 3.2.8.1 Instrument Calibration. 101 3.2.8.2 Sample Controls. 101 3.3 Results. 102 3.3.1 Fungicide Concentration. 102 3.3.1.1 Leaf Tissue. 102 3.3.1.2 Thatch. 105 3.3.1.3 Soil. 109 3.3.1.4 Root Tissue. 112 3.3.2 Percent of Applied Fungicide Recovered. 115 3.3.2.1 Leaf Tissue. 115 3.3.2.2 Thatch. 120 3.3.2.3 Soil. 121 3.3.2.4 Root Tissue. 122 3.4 Discussion. 123 4. FATE OF BENOMYL IN A TURFGRASS SYSTEM WITH AND WITHOUT POST-APPLICATION IRRIGATION.128 4.1 Introduction. 128 4.2 Materials and Methods. 128 4.2.1 Experimental Site. 128 4.2.2 Fungicide Application. 130 4.2.3 Sampling. 130 viii 4.2.4 Storage Samples. 131 4.2.5 Analytical Procedures. 132 4.2.6 Quality Assurance/Quality Control. 134 4.2.6.1 Instrument Calibration. 134 4.2.6.2 Sample Controls. 135 4.3 Results. 136 4.3.1 Fungicide Concentration. 136 4.3.1.1 Leaf Tissue. 136 4.3.1.2 Thatch. 136 4.3.1.3 Soil. 141 4.3.1.4 Root Tissue. 141 4.3.2 Percent of Applied Fungicide Recovered. 146 4.3.2.1 Leaf Tissue.