Economic Thresholds Crop Management Systems Introduction to Nemaplex

1. Economic ThresholdsCrop Management SystemsIntroduction to Nemaplex Nematology 204 May 6, 2013 Howard Ferris Department of Entomology and Nematology University of California, Davis

2. Crop Yield in Relation to Nematode Population Density

3. Annual Crops Critical Point Models Premises: • Target nematode population is resident • Population can be measured with acceptable precision • Population can be measured with acceptable speed • Population increase is relatively slow • Management alternatives require decision prior to planting • Population must be measured prior to planting are these premises valid?

4. Sources of Data • Ferris et al, 1970s and 1980s • Roberts et al, 1980s • Cooke and Thomason, 1970s Some Constraints to Early Adoption • Availability of inexpensive nematicides • Development of resistant varieties in some crops • Publication of thresholds in arcane format

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

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

7. Thresholds by transect Imperial and Coachella Valleys Ventura County Tulare County

8. 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

9. Case Study on Cotton

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

11. Damage Function Parameters for Selected Crops

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

13. Optimizing the Discrete Modelfor a multi-year cropping system

14. 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

16. Perennial Crops / Permanent Plantings Multiple Point Models Premises: • Target nematode population is resident • Population can be measured with acceptable precision • Timeframe for population increase is long • Management alternatives require decision prior to planting and ongoing management as needed • Population must be measured periodically to determine trajectory are these premises valid?

19. Cropping System Design • Agricultural versus Natural systems: • Soil carbon • 2. Soil food webs • 3. Plant-parasitic nematodes

20. Soil Food Web: Resource Flow among Functional Guilds Photosynthates Producers Fixers Sources Opportunists Immobilizers Top Predators Regulaters Consumers Mineralizers Nematodes at each trophic level

21. Food Web Complexity and the Regulation Function Management practices in industrialized agriculture result in: Soil food web simplification Reduction in higher trophic levels We tested evolving nematode predator:prey hypotheses with data from banana plantations in four Central American countries………. Costa Rica, 2008

22. Predators and prey – the Apparent Competition Hypothesis Generalist and Specialist Predators Amplifiable Prey Target Prey Fungal-, bacterial-feeding Nematodes Plant-feeding Nematodes

23. Amplifiable and target prey E2 E1 E6 E4 E5 E3 – the expanded model A=favorable conditions for predators Functional complementarity B=co-location of predators and prey + Other Prey Predator Nematodes A + - + Other Predators B A - B + Amplifiable Prey + Target Prey + + + - Protozoa B + Microbial Biomass Root Associate Nematodes B - + - + Nematophagous Fungi Organic Matter Rhizosphere Bacteria + + + + + + Plant Roots + Litter + External Sources

24. Sugarcane - Australia

25. 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.