1. Robert WoolleyDave Wilson NurseryHickman, CA growers of deciduous fruit, nut & shade trees for commercial growers & the home garden

2. Dave Wilson Nursery • primarily field-grown, trees sold bareroot • some stock grown in containers • 1 to 2 years in ground • zero tolerance for nematodes

3. Dave Wilson Nursery trees sold to commercial growers must be produced under CA Dept of Food & Agriculture (CDFA) Nematode Certification Program CDFA’s Nematode Certification Program requires soil treatment or nematode sampling soil treatment must eliminate nematodes to 4 to 5 feet deep, for 1 to 2 years

4. 3 soil treatments used in CA for control of nematodes in field grown deciduous trees: • methyl bromide with chloropicrin • Telone II (1,3-dicholoropropene) • Vapam (metam sodium)

5. methyl bromide • only soil treatment effective in “heavy” soils • only nematicide in general use that also effectively controls weeds • granted limited use in CA nurseries by Montreal Protocol, under QPS exemption • rates of chloropicrin from odorant to as high as 33% (strawberries up to 50% “pic”) • a “biocide”, so it disrupts soil ecology

6. Telone II • approx 95% of CA tree nursery Telone II treatments are done under tarp--tarping may provide some weed control • use limited by “township caps” • 30 days (minimum) to plant back • putatively more benign to soil ecology than methyl bromide

7. Vapam • requires water as carrier to target pest, but sprinkler application limited as it’s highly volatile • drip application impractical in nurseries • very limited use with Telone II due to cumbersome application rig

8. non-chemical alternatives crop rotation and/or extended fallow -maybe OK--limited by time required mechanical (super-heated water/steam) -questionable efficacy & cost? Star Wars devices -cost? & soil ecology concerns

9. other “alternatives” methyl iodide -little to no interest due to phytotoxicity propargyl bromide -tends to explode Nemacur, Vydate & Furidan (sp?) -registered for use in CA via drip but not used due to impracticality brassicas & other veges -insufficient nematode kill -impractical

10. next steps? • plant breeding for immunity • -very long term but important to • pursue • novel approaches to killing nematodes and controlling weeds & disease -new chemicals? -genomics? • Grow trees solely in containers -the ultimate solution?