AN ABSTRACT OF THE THESIS OF Kathryn J. Merrifield for the degree of Master of Science in Botany and Plant Pathology presented on June 4, 1990. Title: POPULATION DYNAMICS, EXTRACTION, AND RESPONSE TO NEMATICIDE OF THREE PLANT PARASITIC NEMATODES ON PEPPERMINT (MENTHA PIPERITA L.) Redacted Abstract approved: for Privacy Dr. RuSgell E. Ingham The efficiencies of wet sieving/sucrose centrifugation (WS/SC) recovery of Pratylenchus penetrans (59 %), Paratylenchus sp., (80 %), and Criconemella xenoplax (66 %) were established. Baermann funnels (BF) recovered significantly more P. penetrans (p = 0.01) and significantly less (p = 0.01) C. xenoplax than did WS/SC. While densities of P. penetrans in stored soil remained constant over the three days following field sample collection, Paratylenchus sp. and C. xenoplax densities increased significantly on the second day and decreased to their original level on the third day. During mist chamber extraction, P. penetrans continued to emerge from peppermint root tissue for 38 days, but 90 % of the total was recovered after 10 days. The standard core, consisting of 500 g dry soil plus the roots and rhizomes in that soil, was developed to express endoparasitic andectoparasitic nematode densities in peppermint field soil, roots, andrhizomes. Enumerating nematode densities within thedifferent plant- soil components of a particular volume ofsoil more closely describes the total nematodepopulation pressure on the plant growingin that volume of soil. Therefore, endoparasitic nematode population levels wereexpressed as numbers in standard core soil, roots,rhizomes, or total core (soil, root, and rhizomepopulations combined). P. penetrans populations inpeppermint fields peaked in early May, decreased through the summer,peaked again in August, and decreased through the fall to alow winter level. Peaks in the P. penetrans population followed peppermint root weight peaks by 3 to 6 wks. Paratylenchus sp. populations remained atrelatively low levels throughout the year except for a pronouncedpeak in August, which followed the rootweight peak by 3 to 6 wks. The C. xenoplax population also peaked 3to 6 wks after the August root weight peak butfluctuated markedly throughout the remainder of the year. From 70 to 90 % of the total P. penetrans population wasin roots in early May, decreased to 40 to 50 % by late Juneand 20 to 40 % in August. Up to 20 % of the population was inrhizomes on some dates, but therhizome percentage was usually less than 10. Fewer P. penetrans were recovered fromrhizomes during the harsh winter of 1988-89 than during the mild winter of 1989-90. Analysis of point samples (pretreatment, posttreatment, and harvest samples) and area under nematode population curves (AUNPC) were used to compare nematode populations in oxamyl-treated (1.1 kg a.i./ha) and nontreated plots in two peppermint fields through the two growing seasons. Point sample analyses detected significant decreases in treated soil, root, and total standard core P. benetrans populations compared to nontreated populations in several pretreatment and harvest sample dates and in two rhizome harvest sample dates. No treatment differences were observed in Paratylenchus sp. or C. xenoplax populations using this analysis. AUNPC analysis detected significant decreases in several treated root and rhizome P. penetrans populations compared to nontreated populations and in total core populations in field 1 during one growing season and in field 2 during two growing seasons. Significant decreases in C. xenoplax populations were observed in one field during one growing season. Peppermint hay weight was significantly greater in treated than in nontreated plots in one of three fields in 1988 and in one of three fields during 1989. Oil in ml/kg fresh hay weight was significantly lower in treated than in nontreated plots in one of three fields during 1989. No treatment differences were detected in milliliters of oil distilled from 2m2 field area. Peppermint oil production is the final measure of a treatment from a mint grower's perspective. Because oxamyl had no effect on mint oil production, AUNPC appears to be a better measure of parasitic nematode pressure on peppermint, since this method of analysis detected fewer significant differences between nematode populations between treated and non-treated plots. POPULATION DYNAMICS, EXTRACTION, AND RESPONSE TO NEMATICIDE OF THREE PLANT PARASITIC NEMATODES ON PEPPERMINT (MENTHA PIPERITA L.) by Kathryn J. Merrifield A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Completed June 4, 1990 Commencement June 1991 APPROVED: Redacted for Privacy Professor of Botany and Plant Pathology in charge of major iT Redacted for Privacy Head of Departmen f Botany and P t Pathology Redacted for Privacy Dean of Grad/Xte School Day thesis is presented June 4, 1990 Typed for Kathryn J. Merrifield byKathryn J. Merrifield ACKNOWLEDGEMENTS Special gratitude is extended to my major professor, Dr. Russell E. Ingham, for his ideas, counsel,impartation of diverse skills, and invaluable support during my Master's program. Dr. Gene B. Newcomb continually provided valuable, interesting, and timely advice and help. Thanks are also extended to the members of my committee. I am grateful to the members of the Department of Botany and Plant Pathology for their support and encouragement as well as for the award of a teaching assistantship, without which this degree program would not have been undertaken. Help and advice from Sure-Crop Farm Services was foundational to this study. The cooperation and goodwill of Edmund Crowson and Sons and John Hentze are deeply appreciated. Financial support from the Oregon Essential Oil Growers League is gratefully acknowledged. Special thanks are extended to the many friends and associates who have contributed in countless ways to this thesis. DEDICATION To Cinnamon, Brillo, and the late Noodle TABLE OF CONTENTS INTRODUCTION 1 LITERATURE REVIEW 6 Pratylenchus penetrans and other Pratylenchus species 6 Paratvlenchus species 31 Criconemella xenoplax and other Criconematids 37 Effect of Oxamyl on P. penetrans, Paratylenchus sp., Criconemella xenoplax, and Other Nematodes 43 Extraction Methods and their Efficiency 48 EFFICIENCY OF EXTRACTING PRATYLENCHUS PENETRANS, PARATYLENCHUS SP., CRICONEMELLA XENOPLAX, AND MELOIDOGYNE CHITWOODI 109 Materials and Methods 111 Results 122 Discussion 137 Summary 149 POPULATION DYNAMICS OF PRATYLENCHUS PENETRANS, PARATYLENCHUS SP., AND CRICONEMELLA XENOPLAX ON WESTERN OREGON PEPPERMINT 151 Materials and Methods 152 Results 156 Discussion 186 Summary 193 THE EFFECT OF OXAMYL ON POPULATIONS OF PRATYLENCHUS PENETRANS, PARATYLENCHUS SP., AND CRICONEMELLA XENOPLAX AND ON HAY AND OIL YIELD IN WESTERN OREGON PEPPERMINT 195 Materials and Methods 197 Results 204 Discussion 229 Summary 235 LITERATURE CITED 237 LIST OF FIGURES 1. WET SIEVING/SUCROSE CENTRIFUGATION EXTRACTION EFFICIENCY DETERMINATION 115 2. CUMULATIVE BAERMANN FUNNEL RECOVERY OF PRATYLENCHUS PENETRANS, PARATYLENCHUS SP., AND CRICONEMELLA XENOPLAX 133 3. CUMULATIVE BAERMANN FUNNEL RECOVERY OF MELOIDOGYNE CHITWOODI 134 4. CUMULATIVE RECOVERY OF PRATYLENCHUS PENETRANS BY MIST CHAMBER EXTRACTION 136 5. THE HYPOTHETICAL STANDARD CORE, CONSISTING OF 500 g DRY SOIL PLUS ROOTS AND RHIZOMES CONTAINED THEREIN 154a 6. SOIL MOISTURE, FIELDS 1 AND 2 157 7. SOIL MOISTURE, FIELD 3 158 8. STANDARD CORE ROOT WEIGHT, FIELDS 1 AND 2 159 9. STANDARD CORE RHIZOME WEIGHT, FIELDS 1 AND 2 161 10. PRATYLENCHUS PENETRANS IN STANDARD CORE, INCLUDING SOIL, ROOTS, AND RHIZOMES 163 11. PRATYLENCHUS PENETRANS IN STANDARD CORE SOIL, FIELD 1 165 12. PRATYLENCHUS PENETRANS IN STANDARD CORE SOIL, FIELD 2 166 13. PRATYLENCHUS PENETRANS IN STANDARD CORE ROOTS, FIELDS 1 AND 2 168 14. PRATYLENCHUS PENETRANS INSTANDARD CORE RHIZOMES, FIELD 1 170 15. PRATYLENCHUS PENETRANS INSTANDARD CORE RHIZOMES, FIELD 2 171 16. PRATYLENCHUS PENETRANS IN STANDARD CORE: SOIL, ROOTS,AND RHIZOMES, FIELD 1 173 17. PRATYLENCHUSPENETRANS IN STANDARD CORE: SOIL, ROOTS,AND RHIZOMES, FIELD 2 174 18. DISTRIBUTION OF PRATYLENCHUS PENETRANS AMONG COMPONENTS WITHIN A STANDARD CORE, FIELD 1 176 19. DISTRIBUTION OF PRATYLENCHUS PENETRANS AMONG COMPONENTS WITHIN A STANDARD CORE, FIELD 2 177 20. PARATYLENCHUS SP. IN A STANDARD CORE, FIELDS 1 AND 2 180 21. PARATYLENCHUS SP. IN A STANDARD CORE, FIELD 3 181 22. CRICONEMELLA XENOPLAX IN A STANDARD CORE, FIELDS 1 AND 2 183 23. PRATYLENCHUS PENETRANS, PARATYLENCHUS SP., AND CRICONEMELLA XENOPLAX IN A STANDARD CORE, FIELD 1 184 24. PRATYLENCHUS PENETRANS, PARATYLENCHUS SP., AND CRICONEMELLA XENOPLAX IN A STANDARD CORE, FIELD 2 185 25. PRATYLENCHUSPENETRANS IN A STANDARD CORE, FIELD 1 217 26. PRATYLENCHUSPENETRANS IN A STANDARD CORE, FIELD 2 218 27. PARATYLENCHUSSP. IN A STANDARD CORE, FIELD 1 219 28. PARATYLENCHUSSP. IN A STANDARD CORE, FIELD 2 220 29. CRICONEMELLAXENOPLAX IN A STANDARD CORE, FIELD 1 221 30. CRICONEMELLAXENOPLAX IN A STANDARD CORE, FIELD 2 222 31. PARATYLENCHUSSP. IN A STANDARD CORE, FIELD 3 227 LIST OF TABLES 1. Wet Sieving/Sucrose Centrifugation Extraction Efficiency 123 2. Baermann Funnel (BF) Extraction Efficiency of Pratylenchus penetrans, Paratylenchus sp., and Criconemella xenoplax determined by reextraction by Wet Sieving/Sucrose Centri- fugation (WS/SC) and comparison of BF with WS/SC 125 3. Effect of Short Term Cold Storate on Wet Sieving/Sucrose Centrifugation Extraction of Pratylenchus penetrans, Paratylenchus sp., and Criconemella xenoplax