Progress 06/01/02 to 06/01/07
Outputs
Replicated field experiments on alternatives to methyl bromide for soil fumigation in strawberry production were conducted in 2002-04 near Watsonville, CA. Selected beds were fumigated with shank-applied methyl bromide/ chloropicrin (MBC, 67/33) at 325 lb/a (rates per unit treated bed area) and covered with black standard polyethylene or virtually impermeable (VIF) plastic. Chloropicrin at 200 and/or 300 lb/a, InLine (Telone C-35 ) at 283 and 425 lb/a, or iodomethane (33% methyl iodide/ 67% chloropicrin) at 300 lb/a were drip applied in water to beds under plastic and there were non-treated controls. The use of VIF plastic as compared to standard plastic improved the control of buried inoculum of Verticillium dahliae significantly where chloropicrin or InLine was used. The ranking of the five varieties used for the final incidence of plants with Verticillium wilt on nontreated soil (highest incidence 25-85%) was Camino Real, Aromas, Diamante, Camarosa, and Ventana. All
of the fumigation treatments controlled Verticillium wilt adequately in Camino Real and Aromas, while only iodomethane and InLine at the high rate generally gave wilt control equivalent to MBC in Diamante, Camarosa, and Ventana. Control of Verticillium wilt by chloropicrin was generally less than by MBC or InLine with standard plastic, but was improved somewhat with VIF plastic. Most of the chemical fumigation treatments more than doubled total yields and the highest yields in all varieties were most often obtained with InLine. While the effects of the various chemical treatments on the yields of Camino Real, Aromas, and Diamante were generally similar, Camarosa and Ventana usually yielded significantly less on soil treated with chloropicrin. Bacteria were isolated from the bulk soil, rhizospheres and root tissues of strawberry grown in field plots with MBC-fumigated and non-treated soils. Following fumigation, fluorescent Pseudomonas species quickly reached high populations in soil
and on roots. Isolates were identified and tested for antibiosis in cultures of pathogenic fungi isolated from strawberry. Several bacteria, especially Pseudomonas species from rhizospheres in fumigated soils, had antibiosis to one or more fungi. Among bacterial isolates, there was a correlation between antibiosis to fungi and growth promotion of inoculated strawberry plants grown in natural soil under controlled conditions. Bacterial isolates giving consistent growth benefits under controlled conditions were tested in the field for 3 years. Bacterial growth promotion of strawberry following inoculation of bare-root transplants in the field was variable and depended on soil background treatment, strawberry variety, and isolate. Among the combinations of four soil treatments (non-treated, MBC, chloropicrin, and metam sodium) and five Pseudomonas isolates used, 1-2 isolates applied to Camarosa or Aromas on chloropicrin- and/or metam sodium-treated soils gave significant and repeatable
yield increases. A marked strain of one bacterial isolate colonized strawberry roots at high populations for at least 6 months after inoculation in the field.
Impacts
California produces over 80% of the nations strawberry fruit and California nurseries produce nearly 1 billion strawberry runner plants each year. The California strawberry industry relies heavily on methyl bromide fumigation of soil to control soilborne plant pathogens and obtain profitable yields in high-cost production systems. This research project has further identified and optimized some chemical and non-chemical alternatives to methyl bromide for strawberry production. This project also has increased our understanding of microbial mechanisms by which soil fumigation increases the growth and yield of strawberry.
Publications
- Ajwa, H. A., Fennimore, S., Browne, G., Martin, F., Trout, T., Duniway, J., Shem-Tov, S., and Daugovish, O. 2005. Strawberry yield with various rates of chloropicrin and InLine applied under VIF. Abstract #53. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, San Diego, CA, 31 October- 3 November, 2005.
- Browne, G., Duniway, J., Westerdahl, B., Martin, F., Ajwa, H., and Fennimore, S. 2005. Effects of VIF and chloropicrin and InLine rates on survival of nematodes and pathogens in soil. Abstract #50. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, San Diego, CA. 31 October- 3 November, 2005.
- Kabir, Z., Fennimore, S. A., Duniway, J. M., Martin, F. N., Browne, G. T., Winterbottom, C. Q., Ajwa, H. A., Westerdahl, B. B., Goodhue, R. E., and Haar, M. J. 2005. Alternatives to methyl bromide for strawberry runner plant production. HortScience 40(6):1709-1715.
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Progress 01/01/04 to 12/31/04
Outputs
Replicated field experiments on alternatives to methyl bromide for strawberry production were continued in 2003-04 near Watsonville, CA. Selected beds were fumigated with shank-applied methyl bromide/ chloropicrin (MBC, 67/33) at 325 lb/a (rates per unit treated bed area) and covered with standard black polyethylene mulch. Chloropicrin at 300 lb/a, InLine (Telone C-35) at 283 and 425 lb/a, and iodomethane (33 percent methyl iodide/ 67 percent chloropicrin) at 300 lb/a were applied to beds under plastic in water emulsions through drip lines and there were nontreated controls. The ranking of the five varieties used for the final incidence of plants with Verticillium wilt (0-25 percent) on nontreated soil was Camino Real, Aromas, Diamante, Camarosa, and Ventana. All of the fumigation treatments controlled Verticillium wilt in Aromas and Camino Real, while only iodomethane and InLine at the high rate gave control equivalent to MBC in Diamante, Camarosa, and Ventana. Most
of the chemical fumigation treatments more than doubled total yields and the highest yields in all varieties were obtained with InLine at the high rate. While the effects of the various chemical treatments on the yields of Camino Real, Aromas, and Diamante were generally similar, Camarosa and Ventana yielded significantly less on soil treated with chloropicrin. Bacterial growth promotion of strawberry following inoculation of bare-root transplants in the field was variable and depended on soil background treatment, strawberry variety and isolate. Among the combinations of four soil treatments (not treated, MBC, chloropicrin, and metam sodium) and five Pseudomonas isolates used in 2003-04, only one isolate applied to Camarosa and one other applied to Aromas on chloropicrin-treated soil gave significant yield increases (17 and 40 percent, respectively). These two isolates are being characterized fhttp://daisy.uvm.edu/cris/formhelp.htm#pubs 43. Publications:urther. A marked stain of one
bacterial isolate used was found to colonize strawberry roots at high populations for at least 6 months after inoculation.
Impacts
California produces over 80% of the nations strawberries and nearly 1 billion strawberry runner plants each year. The California strawberry industry relies heavily on methyl bromide fumigation of soil to control soilborne plant pathogens and obtain profitable yields in high-cost production systems. This research project is further identifying and optimizing some chemical and non-chemical alternatives to methyl bromide for strawberry production.
Publications
- Fennimore, S. A., Duniway, J. M., Martin, F. N., Browne, G. T., Kabir, Z., Winterbottom, C. Q., Ajwa, H. A., Westerdahl, B. B., Goodhue, R. E., and Haar, M. J. 2003. Alternative fumigants for strawberry nursery production in California: a summary. Abstract #16. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Orlando, FL. 31 October- 3 November, 2004.
- Hao, J. J., Duniway, J. M., and Dopkins, D. M. 2004. Alternatives to methyl bromide for management of Verticillium wilt in strawberry. Phytopathology 94:S39 (Abstract).
- Duniway, J. M. 2004. Alternatives to methyl bromide for strawberry production in California. Page 14, Proceedings 6th International Symposium on Chemical and Non-Chemical Soil and Substrate Disinfestation, Corfu, Greece. 4-8 October, 2004.
- Ajwa, H. A., Fennimore, S., Kabir, Z., Martin, F., Duniway, J., Browne, G., Trout, T., Khan, A., and Daugovish, O. 2004. Strawberry yield with chloropicrin and InLine in combination with metam sodium and VIF. Abstract #38. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Orlando, FL. 31 October- 3 November, 2004.
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Progress 01/01/03 to 12/31/03
Outputs
A field experiment on chemical alternatives to methyl bromide was repeated in 2002-03 near Watsonville, CA. Selected beds were fumigated with shank-applied methyl bromide/ chloropicrin (MBC, 67/33) at 325 lb/a (rates per unit treated bed area) and covered with standard black polyethylene mulch or black virtually impermeable plastic film (VIF). Chloropicrin at 200 and 300 lb/a and InLine (Telone C-35) at 283 and 425 lb/a were applied to beds under plastic in water emulsions through drip lines and there were nontreated controls. The use of VIF plastic as compared to standard plastic improved the control of buried inoculum of Verticillium dahliae significantly where chloropicrin or InLine was used. The ranking of the five varieties used for the final incidence of plants with Verticillium wilt (low to high) on nontreated soil was Camino Real, Aromas, Diamante, Camarosa, and Ventana. Control of Verticillium wilt by chloropicrin was generally less than that by MBC or InLine
with standard plastic, but was improved somewhat with VIF plastic. The effects of fumigation treatments on berry yields varied with the time of harvest and variety. All the chemical fumigation treatments more than doubled total yields and the effects of the various chemical treatments on the yields of Camino Real, Aromas, and Diamante, were generally similar. For the varieties Camarosa and Ventana, InLine at 283 lb/a gave the highest total yields. Ventana plants grown in soil treated with InLine at the higher rate tended to be more vegetative than those in other treatments. Bacterial growth promotion of strawberry following inoculation of bare-root transplants in the field was variable and depended on soil background treatment, strawberry variety and isolate. In nontreated soil, none of the bacteria decreased yield and 2-3 isolates increased yields of both Aromas and Camarosa slightly. While only one isolate increased yield of Camarosa in MBC- or metam sodium-treated soils, several
isolates did so in chloropicrin-treated soil (200 lb/a). Aromas was generally less responsive, but 1-3 bacterial isolates gave measurable increases in yield on chloropicrin- or metam sodium-treated soils. A marked stain of one bacterial isolate used was found to colonize strawberry roots at high populations for at least 6 months after inoculation.
Impacts
California produces over 80% of the nations strawberries and nearly 1 billion strawberry runner plants each year. The California strawberry industry relies heavily on methyl bromide fumigation of soil to control soilborne plant pathogens and obtain profitable yields in high-cost production systems. This research project is further identifying and optimizing some chemical and non-chemical alternatives to methyl bromide for strawberry production.
Publications
- Hao, J. J., Duniway, J. M. and Dopkins, D. M. 2003. Effects of soil fumigants, plastic mulch, and variety on Verticillium wilt of strawberry. Phytopathology 93:S33. Abstract.
- Duniway, J. M., Hao, J. J., Dopkins, D. M., Ajwa, H. and Browne, G. T. 2003. Soil fumigant, plastic mulch, and variety effects on Verticillium wilt and yield of strawberry. Abstract #126. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, San Diego, CA. November 3-6, 2003.
- Duniway, J. M., Hao, J. J., Dopkins, D. M. and Xiao, C. L. 2003. Beneficial effects of rhizobacteria on growth and yield of strawberry. Abstract #44. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, San Diego, CA. November 3-6, 2003.
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Progress 01/01/02 to 12/31/02
Outputs
Chemical alternatives to methyl bromide were used in a replicated field experiment near Watsonville, CA. Selected beds were fumigated with shank-applied methyl bromide/chloropicrin (MBC, 67/33) at 325 lb/a (rates per unit treated bed area) and covered with standard black polyethylene mulch or black virtually impermeable plastic film (VIF). Chloropicrin at 200 and 300 lb/a and InLine (Telone C-35 ) at 283 and 425 lb/a were applied to beds under plastic in water emulsions through drip lines and there were nontreated controls. The use of VIF plastic as compared to standard plastic improved the control of buried inoculum of Verticillium dahliae significantly where chloropicrin or InLine was used. The ranking of the five varieties used for the final incidence of plants with Verticillium wilt (low 15 percent to high 85 percent) on nontreated soil was Camino Real, Aromas, Diamante, Camarosa, and Ventana. Control of Verticillium wilt by InLine in the more susceptible
varieties Camarosa and Ventana was superior to that obtained with MBC, especially where VIF plastic was used. Disease control by chloropicrin was generally less than that by MBC with standard plastic but was improved with VIF plastic. All fumigation treatments effectively controlled weed growth through plant holes in the plastic mulch. The effects of fumigation treatments on berry yields varied with the time of harvest and variety. In general, the varieties giving the highest yields on MBC treated soil (Diamante, Camarosa, and Ventana) also had the largest yield responses to fumigation in comparison to non-fumigated soil. All the chemical fumigation treatments more than doubled total yields and the effects of the various chemical treatments on the yields of Camino Real, Aromas, and Diamante, were generally similar. For the variety Camarosa, the MBC treatment with VIF gave the highest total yield, while the lower rate of InLine gave the highest yield in Ventana. Ventana plants grown in
soil treated with InLine at the higher rate tended to be more vegetative than those in other treatments. Bacterial growth promotion of strawberry following inoculation of bare-root transplants in the field was variable and depended on soil background treatment, strawberry variety and/or location, as well as isolate. Most of the inoculations of transplants in MBC-treated soils decreased yield, and none of the inoculations increased yield significantly in nontreated soils. In soils treated with chloropicrin (200 lb/a) or metam sodium, however, a few of the bacterial isolates increased plant growth and/or berry yield significantly. In the 2001-2002 season, broadcast applications of high-nitrogen organic amendments at only the highest rates used (i.e., 3 tons/a feather meal and 6 tons/a meat and bone meal) reduced Verticillium wilt development in the variety Aromas.
Impacts
California produces over 80 percent of the nations strawberries and nearly 1 billion strawberry runner plants each year. The California strawberry industry relies heavily on methyl bromide fumigation of soil to control soilborne plant pathogens and obtain profitable yields in high-cost production systems. This research project will further identify and optimize some chemical and non-chemical alternatives to methyl bromide for strawberry production.
Publications
- Duniway, J. M., Hao, J. J., Dopkins, D. M., Ajwa, H. and Browne, G. T. 2002. Some chemical, biological, and cultural alternatives to methyl bromide for strawberry. Abstract. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Orlando, FL. November 6-9.
- Hao, J. J., Duniway, J. M., Dopkins, D. M. and Xiao, C. L. 2002. Effects of rhizobacteria on inhibition of soilborne pathogens and growth of strawberry. Phytopathology 92:S34 (Abstract).
- Duniway, J. M., 2002. Chemical alternatives to methyl bromide for soil treatment particularly in strawberry production. Proceedings of International Conference on Alternatives to Methyl Bromide. Sevilla, Spain, 5-8 March. Pages 34-37.
- Duniway, J. M., 2002. Non-chemical alternatives used in the USA on horticultural crops. Proceedings of International Conference on Alternatives to Methyl Bromide. Sevilla, Spain, 5-8 March. Pages 258-60.
- Duniway, J. M., 2002. Status of chemical alternatives to methyl bromide for pre-plant fumigation of soil. Phytopathology 92:1337-1343.
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