Challenges in producing nematode and pathogen free fruit and nut nursery crops in the United States

Authors: Zasada, Inga; WALTERS, T - Washington State University; HANSON, B - University Of California

Submitted to: Outlooks on Pest Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2010
Publication Date: 10/1/2010
Citation: Zasada, I.A., Walters, T.W., Hanson, B.D. 2010. Challenges in producing nematode and pathogen free fruit and nut nursery crops in the United States. Outlooks on Pest Management. 21:246-250.

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that cause ten billion dollars in U.S. crop losses annually. One problem facing growers of high-value fruit and nut nursery crops is the loss of the soil fumigant methyl bromide. Methyl bromide was used to produce fruit and nut nursery crops free of plant-parasitic nematodes. Without methyl bromide this industry, which produces plants for over 1 million ha of bearing fruit and nut trees in the United States, will have to rely upon other chemical and non-chemical pest management practices. The emphasis of this article is to outline the challenges that fruit and nut nursery crop producers will face in the future in managing plant-parasitic nematodes. It is concluded that challenges will include chemical regulatory requirements related to environmental quality and worker and bystander safety, and high control efficacy need to meet nematode certification requirements for sale of fruit and nut nursery plants.

Technical Abstract: To achieve plant-parasitic nematode and soilborne pathogen control, fruit and nut nursery crop producers have relied upon preplant soil fumigation with combinations of methyl bromide and chloropicrin. In the future, the availability of methyl bromide will continue to be curtailed and ultimately eliminated; therefore, other management practices must be identified and integrated into fruit and nut nursery crop production systems. Perennial fruit and nut nursery crops can provide a difficult test of otherwise effective alternative fumigants because the extremely low tolerance for nematode infestation and relatively long growing cycles require pest control efficacy at soil depths of 1.5 m or greater. The future challenges that these industries will face include adopting and integrating relatively new technologies to control plant-parasitic nematodes into existing production systems, the potential economic constraints associated with new technologies, and a constantly changing landscape of fumigant registration and application requirements in the United States. These challenges will be exacerbated by high phytosanitary requirements in California.