Perennial Nursery Summary
Conclusions and Challenges
National and international market expectations for nematode-free nursery stock limit nursery stock producers to alternatives with very high nematode efficacy at significant depths in the soil.
To meet California nursery certification requirements, producers are required to use approved fumigant treatments or conduct a post-production inspection. A failed inspection may result in an essentially non-saleable crop.
Most alternative treatment schedules are based on the use of 1,3-dichloropropene (with or without chloropicrin), a fumigant that faces its own serious and evolving regulatory issues in California.
No currently available alternative fumigant can be used in to meet certification requirements in nurseries with fine-textured soil at registered rates.
Methyl iodide, the alternative with performance most similar to methyl bromide, is not currently registered in the U.S. due to a voluntary withdawal by the manufacturer.
Concerns over control of non-quarantine pests such as weeds and fungal and bacterial pathogens in the short- and long-term further limit adoption of alternatives with a narrower pest control spectrum.
- Containerized nursery stock productions systems are being used in some parts of the industry but the production costs, market acceptance, and long-term viability of this system have not been addressed at the required scale.
Adoption of methyl bromide alternatives, where they exist, in the perennial crop nursery industry will ultimately be driven by state and federal regulations and economics. Although dependent on heavily regulated alternative fumigants, viable alternatives are available for some growers with coarse-textured soil. However, if alternatives such as 1,3-dichloropropene become more difficult to use due to shortages or increasingly stringent regulations, this may provide only a short-term solution with no backup plan. Unfortunately, no viable alternatives exist for California nurseries with fine-textured soil; absent new alternatives or changing regulations, some of these operations may be unable to produce certified nursery stock in the complete absence of methyl bromide. While significant challenges remain for this industry, we encourage a full evaluation of the risks and benefits of nursery fumigation on the productivity of perennial cropping systems around the world.
Perennial Nursery Literature and Acknowledgements
We would like to acknowledge the following cooperators, colleagues, contributors, and supplemental funding sources:
California Fruit Tree, Nut Tree, and Grapevine Improvement Advisory Board
Dave Wilson Nursery
Garden Rose Council
Jackson and Perkins
Ken Smith Roses
LE Cooke Nursery
Niklor Chemical Company
Sierra Gold Nursery
The Nursery Company
Tri Cal Inc.