Nematode Thresholds and Damage Levels for California Crops

1. Nematode Thresholdsand Damage LevelsforCalifornia Crops Howard Ferris

2. Some of those involved…. • Dan Ball • Larry Duncan • Pete Goodell • Joe Noling • Diane Alston • Sally Schneider • Lance Beem

3. Thresholds by field plot • South Coast Field Station • USDA Shafter • Tulelake

4. Thresholds by transect • Imperial and Coachella Valleys • Ventura County • Tulare County

5. Seinhorst Damage Function • Y=m+(1-m)z(Pi-T) • Y=relative yield • m=minimum yield • Z=regression parameter • Pi=population level • T=tolerance level • Based on preplant population levels – measured or predicted from overwinter survival rates

6. Case Study on Cotton

7. Case Study on Cotton Meloidogyne incognita, J2/250 cc soil

8. Damage Function Parameters for Selected Crops

9. Thresholds and Expected Yield Loss Meloidogyne incognita, J2/250 cc soil; adjusted for extraction efficiency

10. Expected Damage Meloidogyne chitwoodi; summer crop potato; Klamath Basin Fall population levels; adjusted for extraction efficiency

11. Thresholds and Expected Yield Loss Heterodera schachtii, eggs/100g soil Sugarbeets Expected % yield loss at different preplant nematode densities Data from P.A. Roberts

12. Optimized Discrete Model

13. Annual Population Change (Host Crop) 120000 100000 80000 60000 Pi1 * (Pi2/Pi1) 40000 20000 0 0 500 1000 1500 2000 Pi1

14. Pi1 Annual Population Change (Non-host) Pi2 1400 Pi3 1200 1000 800 Pi(t+x) 600 400 200 0 0 500 1000 1500 2000 Pi(t)

15. 1600 1400 1200 1000 800 Pi(t+x) 600 400 200 0 0 1 2 3 4 5 6 7 8 Years After Planting Host Crop

17. Perennial Crop Considerations

19. Year 1 Year 2 100 12000 10000 80 8000 60 LU LU AUC AUC 6000 40 LT LT 4000 20 NU NU 2000 0 NT NT 0 0 1000 2000 3000 0 1000 2000 3000 DD DD Year 3 30000 25000 20000 LU AUC 15000 LT 10000 NU 5000 0 NT 0 1000 2000 3000 DD

20. Some References Benedict, J.H., K.M. El-Zik, L.R. Oliver, P.A. Roberts, and L.T. Wilson. 1989. Economic injury levels for cotton pests. Chapter 6. In: Integrated Pest Management Systems and Cotton Production. R.E. Frisbie, K.M. El-Zik, and L.T. Wilson (eds.). John Wiley and Sons, New York. Pp. 121-153. Cooke, D. A., and I. J. Thomason. 1979. The relationship between population density of Heterodera schachtii, soil temperature, and sugarbeet yields. Journal of Nematology 11:124-128. Duncan, L. W. and H. Ferris. 1983. Effects of Meloidogyne incognita on cotton and cowpeas in rotation. Proceedings of the Beltwide Cotton Production Research Conference: 22-26. Ferris, H. 1984. Probability range in damage predictions as related to sampling decisions. Journal of Nematology 16:246-251. Ferris, H. 1985. Population assessment and management strategies for plant-parasitic nematodes. Agricultural, Ecosystems and Environment 12(1984/85):285-299. Ferris, H., D. A. Ball, L. W. Beem and L. A. Gudmundson. 1986. Using nematode count data in crop management decisions. California Agriculture 40:12-14. Ferris, H., H. L. Carlson and B. B. Westerdahl. 1994. Nematode population changes under crop rotation sequences: consequences for potato production. Agronomy Journal 86:340-348. Ferris, H., P. B. Goodell and M. V. McKenry. 1981. Sampling for nematodes. California Agriculture 35:13-15. Goodell, P.B., M. A. McClure, P. A. Roberts, and S. H. Thomas 1997. Nematodes. In: Integrated Pest Management for Cotton in the Western Region of the United States. 2nd edition. Univ. of California Publ. No. 3305. Pp. 103-110. Roberts, P.A. and G.D. Griffin. 1994. The economic feasibility of management alternatives. In: Quantifying Nematode Control. G.D. Griffin and P.A. Roberts (eds.). Western Regional Research Publication #149, Utah State University Press, Logan, UT. Pp. 23-49. Roberts, P.A. and I.J. Thomason. 1981. Sugarbeet Pest Management: Nematodes. Univ. of California Special Publ. No. 3272. 32 pages.

21. References Burt, O. R. and H. Ferris. 1996. Sequential decision rules for managing nematodes with crop rotations. J. Nematology 28:457-474. Chen, J., J.R. Carey and H. Ferris. 2001. Comparative demography of isogenic populations of Caenorhabditis elegans Expt. Gerontology 36:431-440. Ferris, H. 1978. Nematode economic thresholds: derivation, requirements and theoretical considerations. J. Nematology 10:341-350. Ferris, H. 1985. Density-dependent nematode seasonal multiplication and overwinter survivorship: a critical point model. J. Nematology 17:93-100. Hsin, H. and C. Kenyon. 1999. Signals from the reproductive system regulate the lifespan of C. elegans. Nature 399:362-366. Kim D.G. and H. Ferris. 2001. Relationship between crop losses and initial population densities of Meloidogyne arenaria in winter-grown oriental melon in Korea. J. Nematology (subm.) Noling, J.W. and H. Ferris. 1987. Nematode-degree days, a density-time model for relating epidemiology and crop losses in perennials. J. Nematology 19:108-118. Seinhorst, J.W. 1965. The relationship between nematode density and damage to plants. Nematologica 11:137-154. Seinhorst, J.W. 1967. The relationship between population increase and population density in plant parasitic nematodes. II. Sedentary nematodes. Nematologica 13:157-171. Somers, J.A., H.H. Shorey and L.K. Gaston. 1977. Reproductive biology and behavior of Rhabditis pellio (Schneider) (Rhabditida:Rhabditidae). J. Nematology 9:143-148. More information: http://plpnemweb.ucdavis.edu/nemaplex