Strawberries
Muramoto, J., Gliessman, S. R., Schmida, D., Stephens, R., Shennan, C., and Swezey, S. L. 2004. Nitrogen Dynamics in an Organic Strawberry Production System. In: Proceedings of California Organic Production and Farming in the New Millennium: A Research Symposium. The International House, University of California, Berkeley, CA. pp. 131-134. University of California Sustainable Agriculture Research and Education Program (UC-SAREP).
Abstract: Optimizing nitrogen (N) management in organic strawberries on the central coastal California is a challenge because of high N sensitivity and the long growth period of strawberries, transplanting immediately followed by the winter rainy season and unpredictability of N mineralization from organic fertilizers and soil organic matter. Moreover, research-based information on N fertility management in organic strawberries is lacking. In a replicated on-farm organic rotation trial in Moss Landing, California, N dynamics in an organic strawberry production system was monitored for two years. In the first year, we examined the grower's current N-management practice, and an improved N-management practice was demonstrated in the second year. Fertility management practices, soil inorganic N content (0-60cm deep), and fruit yield, plant biomass, and N content of strawberries (cv. Aromas) were monitored. Changes in cumulative daily N uptake of strawberries were calculated and N- loss from the root zone (0-30cm deep in the bed area) during the winter rainy season was estimated. We used a Monte Carlo simulation method to express statistical variability of the results. In the winter rainy season of the first year, we observed 214 kg-N ha-1 of inorganic N –loss from the root zone within 20 weeks after planting. Plastic mulch was applied 7 weeks after the planting. Marketable fruit yield was 38.7 tons ha-1 with a total N application rate of 255 kg ha-1. Total N uptake of strawberries was ~120 kg ha-1 and about 80% of this occurred in the later half of the growth period. In the second year, we adopted pre-plant plastic mulch application and adjusted basal/supplemental organic fertilizer-N rates to better synchronize the N supply with the plant N demand. As a result, although the residual soil inorganic-N was much lower than the first year, the N-loss during the rainy season was decreased to 13 kg-N ha-1, while maintaining fruit yield a similar to the first year.
Link: http://envs.ucsc.edu/shennan/Joji/muramoto_ccbc04.pdf
Research Update. 2005. The Cultivar, 23, (1), 9-11, Center for Agroecology and Sustainable Food Systems, University of California, Santa Cruz, CA.PDF
Abstract: Researchers are looking at the best ways to adjust fertilizer and compost levels and application timing in order to meet crop demands throughout the season while decreasing the loss of nitrogen from the system.”
Link: Brown_2005.pdf
Bull, C.T., Muramoto, J. Koike S., Leap,
J. Shennan, C. Goldman, Polly. Strawberry
Cultivars and Mycorrhizal Inoculants Evaluated in California Organic
Production Fields. Plant Management Network.
27 May 2005.
Abstract: Thirteen commercial strawberry cultivars were evaluated in side-by-side comparisons in five experiments in organic strawberry production fields in central California. Seven cultivars were common to all five experiments; six additional cultivars were included in one to four of the experiments. Of the seven cultivars that were evaluated in all five experiments, the largest market yield was consistently obtained from Aromas, Seascape, or Pacific. Preliminary analyses detected a strong positive correlation between total fruit yield and the nitrogen status of plants, suggesting characteristics in nitrogen uptake and metabolism may be a significant factor in determining yield of commercial strawberry cultivars tested in organic fields. None of the seven commercially prepared mycorrhizal inoculants tested resulted in an increased marketable fruit yield in organic or non-fumigated fields. However, the effects of the treatments on mycorrhizal colonization and total yield varied among experiments. For example, in one of six experiments, a commercial inoculant increased total yield over the nontreated control but did not influence marketable fruit yield.
Link: http://www.plantmanagementnetwork.org/pub/cm/research/2005/strawberry/
Muramoto, J., Gliessman, S. R., Schmida,
D., Shennan, C., and Swezey, S. 2004.
Nitrogen Dynamics in an Organic Strawberry Production System.
Proceedings of California Organic Production and Farming in the New Millennium:
A Research Symposium. The International House, University of California,
Berkeley, pp.131-134. (Invited)
Abstract: Optimizing nitrogen (N) management in organic strawberries on the central coastal California is a challenge because of high N sensitivity and the long growth period of strawberries, transplanting immediately followed by the winter rainy season and unpredictability of N mineralization from organic fertilizers and soil organic matter. Moreover, research-based information on N fertility management in organic strawberries is lacking. In a replicated on-farm organic rotation trial in Moss Landing, California, N dynamics in an organic strawberry production system was monitored for two years. In the first year, we examined the grower’s current N-management practice, and an improved N-management practice was demonstrated in the second year. Fertility management practices, soil inorganic N content (0-60cm deep), and fruit yield, plant biomass, and N content of strawberries (cv. Aromas) were monitored. Changes in cumulative daily N uptake of strawberries were calculated and N- loss from the root zone (0-30cm deep in the bed area) during the winter rainy season was estimated. We used a Monte Carlo simulation method to express statistical variability of the results. In the winter rainy season of the first year, we observed 214 kg-N ha-1 of inorganic N –loss from the root zone within 20 weeks after planting. Plastic mulch was applied 7 weeks after the planting. Marketable fruit yield was 38.7 tons ha-1 with a total N application rate of 255 kg ha-1. Total N uptake of strawberries was ~120 kg ha-1 and about 80% of this occurred in the later half of the growth period. In the second year, we adopted pre-plant plastic mulch application and adjusted basal / supplemental organic fertilizer-N rates to better synchronize the N supply with the plant N demand. As a result, although the residual soil inorganic-N was much lower than the first year, the N-loss during the rainy season was decreased to 13 kg-N ha-1, while maintaining fruit yield a similar to the first year.
Link: http://envs.ucsc.edu/shennan/Joji/muramoto_ccbc04.pdf
For a complete list of research by Joji Muramoto, Center for Agroecology and Sustainable Food Systems, University of California, Santa Cruz on Sustainable fertility and pest management strategies in organic strawberries and organic vegetables in California: http://www.agroecology.org/people/joji.htm
Walter, M., Snelling, C., Boyd-Wilson,
K. S. H., Williams, G., and Langford, G. I. 2005. Evaluation
of organic strawberry runner production. HortTechnology
15 (4):787-
796 PDF
Abstract: System requirements for organic runner production were determined during the 2001-02 and 2002-03 seasons. Production costs per plant were determined. In both seasons, organically produced runners were evaluated in the field and compared with conventionally produced runners for yield and fruit quality under organic BioGro™ certified production conditions. Several cultivars were studied, with the main emphasis on cv. Sunset and cv. Aromas. The curtain system, where mother plants grew on benches in a tunnel house and the first two runners were potted into growth substrate, produced approximately 200 plug plants m-2, and was the best system. Diseases and pests were mostly controlled by sanitation. The least preferred system was bin production, where mothers were allowed to run into a bin containing the growth substrate in the tunnel house. Approximately 100 bare-rooted plants were produced per square metre. Botrytis infections occurred due to the dense strawberry canopy. The cost per runner was NZ$0.50 and $0.86/plant for the curtain and bin systems, respectively. Production of organic runners under cover allowed earlier (March vs May) planting, which produced yield increases of approximately 200 g/plant. This more than compensated for the additional cost of organic runners compared with conventional bare-rooted runners.
Link: http://www.actahort.org/members/showpdf?booknrarnr=708_108
LaMondia, J. A., Elmer, W. H., Mervosh, T. L., and Cowles, R. S. 2002. Integrated management of strawberry pests by rotation and intercropping. Crop Protection. 21 (9):837. PDF
Abstract: Saia’ oats (Avena strigosa) and ‘Triple S’ sorgho-sudangrass (Sorghum bicolor x S. sudanense) were investigated as rotation crops and as interplanted companion crops the following year for their individual and combined effects on strawberry root pathogens, weed species composition and density, weevil and white grub densities in soil, rhizosphere microbial populations, nutrient content of crowns, and strawberry yield. Treatments were compared with ‘Garry’ oats (Avena sativa) or continuous ‘Honeoye’ strawberries at two sites in Connecticut. Lesion nematode (Pratylenchus penetrans) recovery was greater from Garry oats than for strawberry, Saia oats or sorgho-sudangrass. Bait root infection by Rhizoctonia fragariae was highest for strawberry. Weed density was inversely related to rotation crop density. White grub larvae were most common in strawberry. Rotation crop did not affect isolation of Rhizoctonia or Pythium in 1996 or 1997. Weed growth in plots in 1996 was suppressed after sorgho-sudangrass in 1995, but not in 1997. Intercropping was similar to herbicide application, but only when the intercrop was present. Rotation crop did not affect pathogen recovery from roots of 2-year old strawberry crowns. Numbers of European chafer larvae were greatest in Saia oats, which may have been attractive to gravid females. Japanese and Asiatic garden beetle populations were positively correlated with soil organic matter. Rhizosphere populations of fluorescent pseudomonads were unaffected by treatment. Fruit yield (1997) was greatest in plots previously planted to Garry or Saia oats and least after sorgho-sudangrass, possibly due to phytotoxic properties of residues. Production of rotation crops such as sorgho-sudangrass or Saia oats may suppress pathogen densities, weeds, and white grub densities prior to planting strawberries but may also adversely affect strawberry growth and yield.
Link: LaMondia_2002.pdf
Black, B. L., Enns, J. M., and Hokanson, S. C. 2002. A comparison of temperate-climate strawberry production systems using eastern genotypes. HortTechnology 12 (4):670-675. PDF
Link: Black_2002.pdf
Bolda, M., Tourte, L., Klonsky, K., and
De Moura, R. L. 2004. Sample costs
to produce strawberries: Central coast region. University of California
Cooperative Extension
Abstract: The sample costs to produce strawberries in the Central Coast Region - Monterey and Santa Cruz counties are presented in this study. The study is intended as a guide only, and can be used to make production decisions, determine potential returns, prepare budgets and evaluate production loans. The practices described are based on production procedures considered typical for this crop and area, and will not apply to every farm.
Link: http://www.agecon.ucdavis.edu/uploads/cost_return_articles/strawcc2004.pdf
Bolda, M., Tourte, L., Klonsky, K., and
Bervejillo, J. E. 2003. Sample costs
to produce organic strawberries: Central coast, Santa Cruz and
Monterey
Counties. University of California Cooperative Extension.
Abstract: Sample costs to produce organic strawberries
in the Central Coast Region--Santa Cruz and Monterey Counties--are presented
in this study. The study is intended as a guide only, and can be used
to make production decisions, determine potential returns, prepare budgets
and evaluate production loans. The practices described are based on production
procedures considered typical for this crop and area, and will not apply
to every farm. Sample costs for labor, materials, equipment and custom
services are based on current figures. A blank column, “"Your
Cost", is provided to enter your actual costs on Tables 1 and
2.
The hypothetical farm operation, production practices, overhead, and calculations
are described under assumptions. For additional information or explanation
of calculations used in the study call the Department of Agricultural
and Resource Economics, University of California, Davis, (530) 752-3589
or the UC Cooperative Extension office in your county. Sample Cost of
Production Studies for many commodities from 1931 to the present are available
and can be requested through the Department of Agricultural and Resource
Economics, UC Davis, (530) 752-1515. Current studies can be downloaded
from the department Web site http://coststudies.ucdavis.edu or obtained
from selected county UC Cooperative Extension offices.
Link: http://www.agecon.ucdavis.edu/uploads/cost_return_articles/strawborgcc03.pdf
Carter, Colin A., James A. Chalfant, Rachael E. Goodhue, Frank M. Han, Massimiliano DeSantis. The Methyl Bromide Ban: Economic Impacts on the California Strawberry Industry. Review of Agricultural Economics- Volume 27, Number 2 Pages 181-197. PDF
Abstract: California strawberry production accounts for 18% of total methyl bromide use in U.S. agriculture. Under the Montreal Protocol, methyl bromide was slated to be banned in the United States in 2005. A critical use exemption was obtained for U.S. agriculture for 2005 and 2006, but the phaseout of methyl bromide continues. We examine the ban's effects on the California strawberry industry, and on individual production regions in the state. Under the most likely scenario, industry revenue will decline by 6–17% due to the ban. The effects will differ by region, due to seasonal differences in demand and production, and the possibility of increased foreign competition.
Link: http://www.blackwell-synergy.com/doi/abs/10.1111/j.1467-9353.2005.00220.x
Goodhue, Rachael E., Steven A. Fennimore,
and Husein A. Ajwa. The Economic
Importance of Methyl Bromide: Does the California Strawberry Industry
Qualify for a Critical Use Exemption from the Methyl Bromide Ban? Review
of Agricultural Economics- Volume 27, Number 2- Pages 198-211.
Abstract: Methyl bromide has been applied to California strawberries for forty years. However, it will be banned in the United States and other developed countries in 2005. Critical use exemptions provide a mechanism that allows its continued use after this date for industries that do not have technically and economically feasible alternatives, and are consequently subject to significant market disruption. Integrating scientific and economic results from a multidisciplinary research project, we evaluate whether California strawberries are eligible for a critical use exemption.
Link: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=876705
H. Brett Highland, Muscador Biofumigant--An Update on a Promising Methyl Bromide Alternative from AgraQuest, Inc.
Abstract: The biofumigant (common name Muscodor, experimental
number QRD 300, proposed
trade names Andante, Glissade, Arabesque) is composed of the fungus Muscodor
albus,
and the and active ingredients it produces. Originally an endophytic fungus
isolated from
the internal bark of a cinnamon tree in Honduras, this fungus is a naturally
occurring
biofumigant that will be used in field and greenhouse vegetable, ornamental
and fruit
production as a soil fumigant. It is a biologically based product and
the active ingredient
(Muscodor albus), produces a series of natural volatiles that negatively
affect plant root
pathogens and nematodes, and can be used in field bedded production as
a methyl
bromide replacement product. QRD 300 is non toxic, environmentally benign,
will be
safe for workers, and will have a short re-entry interval. Target organisms
that Muscodor
has been shown to have extremely effective activity on include Rhizoctonia,
Pythium,
Phytophthora, Fusarium, Ralstonia and Sclerotinia. Trials are being continued
to
evaluate its efficacy on nematodes species, and activity has been shown
on the root knot
nematode Meloidogyne incognita, sting and lesion nematodes. The product
has received
EPA section 3 approval for use, and final stability and formulation studies
are now being
conducted. Anticipated commercial sales are third quarter, 2007.
Link: MuscadorAgraQuest07.pdf
Potatoes
For an non-technical example of how rotating mustard with potatoes is being used effectively to replace of fumigants, see PANNA Magazine, Spring 2007: "Spread the News: Mustard Can Drive Away Pests".
Benbrook, et.al. Monitoring Progress in Reducing Reliance on
High-Risk Pesticides in
Wisconsin Potato Production. Monitoring Pesticide Risks.
Abstract: A methodology is presented to monitor progress
in reducing use of high-risk pesticides in potato production. Multiattribute
toxicity factors are calculated by active ingredient that reflect each
pesticide’s inherent acute and chronic toxicity to mammals; toxicity
to birds, fish and small aquatic organisms; and compatibility with biointensive
Integrated Pest Management. These factors are then used to estimate pesticide-specific
toxicity units (toxicity factor values multiplied by pounds of active
ingredient applied).
Wisconsin potato industry baseline toxicity units by type of pesticide
and for 11-targeted higher-risk pesticides are presented for 1995, reductions
in toxicity units are reported in 1997 and 1999, and reductions achieved
in a commercial scale experimental field in 2000 are presented.
Link: http://ipcm.wisc.edu/LinkClick.aspx?fileticket=6xbkcZKmuso%3D&tabid=87&mid=643
Lynch, Sarah, Deana Sexson, Chuck Benbrook,
et.al. Accelerating Industry-Wide
Transition to Reduced-Risk Pest Management Systems: A Case Study
of the
Wisconsin Potato Industry.
Abstract: Farmers are under increasing pressure to develop
and utilize less toxic methods of pest control. Federal regulations, including
the Food Quality Protection Act (FQPA) and the Clean Water Act (CWA),
constrain producers’pest management choices and could eliminate
some widely used pesticides. Farmers and others in the food supply chain
are responding to consumer concerns about pesticides by creating new market
opportunities for products grown using more environmentally sensitive
production systems.
Those interested in a viable agricultural sector, are challenged to develop
a proactive approach that enhances growers' ability to take advantage
f marketplace opportunities while still complying with regulatory
change. Here, we report on the progress of a project that established
performance indicator, targets, and timetables designed to accelerate
adoption of economically viable biointensive IPM
practices while reducing the use and reliance on high-risk pesticides.
We describe the results of the first three years of this initiative, focusing
specifically on pesticide risk reduction results.
Link: http://ipcm.wisc.edu/LinkClick.aspx?fileticket=%2BWgxToTK6lE%3D&tabid=87&mid=643
Davis, J. R., Huisman, O. C., Westermann, D. T., Hafez, S. L., Everson, D. O., Sorensen, L. H., and Schneider, A. T. 1996. Effects of green manures on Verticillium wilt of potato. Phytopathology 86 (5): 444-453.
Abstract: Two field studies were conducted to investigate the effects of green manure treatments on Verticillium wilt of potato (cv. Russet Burbank) caused by Verticillium dahliae. Each study involved the use of a sudangrass (Sorghum vulgare var. sudanense 'Monarch') green manure treatment and a fallow treatment for either 2 or 3 years prior to growing potato. In addition to sudangrass, comparisons also were made with several green manure treatments, including Austrian winter pea (Pisum sativum 'Austrian winter'), two cultivars of rape (Brassica napus var. napus 'Dwarf Essex' and 'Bridger'), rye (Secale cereale), oat (Avena sativa 'Monida'), and corn (Zea mays 'Jubilee'). Verticillium wilt of potato was best controlled after green manure treatments of either sudangrass or corn ; after these treatments, yields were increased above all other treatments. Wilt was most severe when potato followed the fallow treatment and intermediate following rape, Austrian winter pea, oat, and rye. Wilt incidence was positively correlated with V. dahliae colonization in apical stems but was not significantly related to other pathogens (Pratylenchus neglectus, Colletotrichum coccodes, Rhizoctonia solani Ag-3) or to effects of green manure treatments on preplant nutritional effects of N, P, or K.
Link: http://cat.inist.fr/?aModele=afficheN&cpsidt=3080761
Nunez, Joe. Use of Cover Crops to Suppress Soilborne Pests in
Potato. 2002-2003. UC
Cooperative Extension, Kern County, 1031 South Mount Vernon Ave.,
Bakersfield, Ca 93307.
Abstract:
Link: http://www.cekern.ucdavis.edu/newsletterfiles/Kern_Vegetable_Crops7598.DOC
Wyman, Jeff. 1992. Organic potatoes: They can be grown, but can
they be profitable?
Department of Entomology, University of Wisconsin-Madison.
Link: Organic potatoes, U. Wisconsin
Carrots
P. A. Roberts, J. Nunez, The Potential of Nematode-Resistant Carrots to Reduce Soil Fumigation and VOC Emissions, presentation at California Department of Pesticide Regulation Conference on Pesticide VOCs, May 20, 2007.
Link: http://www.cdpr.ca.gov/docs/emon/vocs/vocproj/poten_nematode_resist.pdf
K. Tupper, Fumigation: Soon a thing of the past for California carrot growers, PANNA Magazine, Fall 2006.
Link: http://www.panna.org/magazine/fall2006/solutionsFumigations.html
Professor Philip A. Roberts, University of California Riverside
Research Description : Dr. Roberts' research focuses on the integrated management of plant parasitic nematodes. A major emphasis is placed on the identification, characterization, and development of host plant resistance to root-knot nematodes for genetic improvement of crops. Current work includes studies of resistance gene inheritance, development of gene markers, genome mapping, and gene transfer. Research on the genetic resistance and associated traits in crop plants to root-knot nematodes is organized in the areas of: 1) identifying new sources of resistance genes; 2) nature, inheritance and molecular characterization of resistance genes; 3) introgressing resistance for breeding line and crop improvement for warm/arid environments using classical and novel techniques; 4) assessing and implementing resistant and tolerant lines and cultivars in the field in appropriate cropping systems; and 5) studying variability of parasitic specificity within and between nematode species.
Link: http://www.faculty.ucr.edu/~proberts/
Tomatoes
E. Grimme and N. K. Zidack, 2007, Comparison of Muscodor albus
Volatiles with a Biorational Mixture for Control of Seedling Diseases
of Sugar Beet and Root-Knot Nematode on Tomato, Plant Disease, 91(2):
220-225.
A biorational synthetic mixture of organic components mimicking key antimicrobial
gases produced by Muscodor albus was equivalent to the use of live M.
albus for control of seedling diseases of sugar beet (Beta vulgaris) caused
by Pythium ultimum, Rhizoctonia solani AG 2-2, and Aphanomyces cochlioides.
The biorational mixture provided better control than the live M. albus
formulation for control of root-knot nematode, Meloidogyne incognita,
on tomato (Lycopersicon esculentum). The biorational mixture provided
control of damping-off equal to a starch-based formulation of the live
fungus for all three sugar beet pathogens, and significantly reduced the
number of root-knot galls on tomato roots compared with a barley-based
formulation. Rate studies with the biorational mixture showed that 2 and
0.75 µl/cm3 of soil were required to provide optimal control of
Rhizoctonia and Pythium damping-off of sugar beet, respectively. Five
microliters of biorational mixture per milliliter of water was required
for 100% mortality in 24 h for Meloidogyne incognita in in vitro studies.
In in vivo studies, 1.67 µl of the biorational mixture/cm3 of sand
resulted in fewer root-knot galls than a Muscodor albus infested ground
barley formulation applied at 5 g/liter of sand.
Link: http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-91-2-0220
Tomato Year-Round IPM Program, University of California, Davis
Link: http://www.ipm.ucdavis.edu/PMG/selectnewpest.tomatoes.html
M. Gene, K. M. Klonsky & R. L. De Moura, 2001. Sample Costs to Produce Processing Tomatoes, University of California Cooperative Extension.
Link: http://www.agecon.ucdavis.edu/outreach/crop/cost-studies/TomsSV2001.pdf
K. Klonsky, L. Torte & D. Chaney. Production Practices and Sample Costs for Organic Processing Tomatoes in the Sacramento Valley, University of California Cooperative Extension, 1993-1994 (Davis, CA).
Link: http://vric.ucdavis.edu/veginfo/topics/prodcosts/organictom.html
Cauliflower
Koike, S., and Subbarao, K. V. 2000. Broccoli Residues Can Control Verticillium Wilt of Cauliflower. Calif. Agric. 54 (3):30-33.PDF
Abstract: Verticillium wilt, a damaging
disease f cauliflower, was successfully managed in a multiple-year
field study by incorporating broccoli residues into infested soil. In
a study conducted from 1993 to 1995 in the Salinas Valley, cauliflower
disease incidence and severity were consistently and significantly reduced
in the broccoli residue plots when compared with no broccoli. The commercial
standard plots fumigated with methyl bromide + chloropicrin had the lowest
disease incidence and severity. In both years of our tarping study, Verticillium
wilt severity was lowest in the metham sodium treatment. The cauliflower-Verticillium
host-pathogen system therefore can act as a model for controlling soil-borne
diseases without the use of synthetic chemicals.
Link: http://californiaagriculture.ucop.edu/0003MJ/pdf/broccoli.pdf
Shetty, K. G., Subbarao, K. V., Huisman, O. C., and Hubbard, J. C. 2000. Mechanism of Broccoli-Mediated Verticillium Wilt Reduction in Cauliflower. Phytopathology. 90 (3):305-310.
Abstract: Broccoli is resistant to Verticillium dahliae infection and does not express wilt symptoms. Incorporation of broccoli residues reduces soil populations of V. dahliae. The effects of broccoli residue were tested on the colonization of roots by V. dahliae, plant growth response, and disease incidence of both broccoli and cauliflower in soils with different levels of V. dahliae inoculum and with or without fresh broccoli residue amendments. The three soils included a low-Verticillium soil, a high-Verticillium soil, and a broccoli-rotation soil (soil from a field after two broccoli crops) with an average of 13, 38, and below-detectable levels of microsclerotia per g of soil, respectively. Cauliflower plants in broccoli-amended high-Verticillium soil had significantly (P ≤ 0.05) lower wilt incidence and severity than did plants in unamended soil. An immunohistochemical staining assay utilizing a monoclonal antibody specific to V. dahliae was used to determine colonization of the root cortex. Despite the absence of wilt symptoms, broccoli roots were colonized by V. dahliae. In high-Verticillium soil, the broccoli residue amendment caused a marked reduction in colonization rate of V. dahliae per unit of inoculum on both cauliflower and broccoli roots. In addition to its detrimental effects on the viability of microsclerotia in soil, broccoli residue may also have an inhibitory effect on the root-colonizing potential of surviving microsclerotia.
Link: http://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO.2000.90.3.305
Subbarao, K. V., Hubbard, J. C., and Koike, S. T. 1999. Evaluation of Broccoli Residue Incorporation into Field Soil for Verticillium Wilt Control in Cauliflower. Plant Dis. 83 (2):124-129.
Abstract: Wilt incited by Verticillium dahliae has
recently become an important disease on cauliflower in the Salinas Valley.
Although broccoli is closely related to cauliflower, wilt has not occurred
on this host and V. dahliae isolates from cauliflower were weakly
pathogenic on broccoli in greenhouse inoculations. In this study, the
effectiveness of broccoli residues on propagule attrition in soil and
wilt incidence on cauliflower was determined in a commercial field infested
with V. dahliae microsclerotia. The treatments were broccoli
residue with tarp, broccoli residue without tarp, chloropicrin, metham
sodium, control with tarp, control without tarp, cauliflower followed
by cauliflower, and cauliflower followed by fallow. Approximately 200
kg of chopped broccoli was uniformly disk incorporated into the corresponding
plots (36 m2). Densities of V. dahliae microsclerotia were determined
at 0, 30, 90, and 145 days after treatment in 1993 and 0, 30, 74, 109,
and 140 days after treatment in 1994 using the modified Anderson sampler
technique. Cauliflower cultivar White Rock was planted in all plots. Plant
height, number of marketable heads, head weight, and wilt severity were
determined at maturity. Even though the pre-treatment number of V.
dahliae propagules in broccoli-treated and control plots were similar,
by the end of the cauliflower cropping season numbers either were the
same or increased in control plots compared with a reduction in numbers
in broccoli residue-treated plots during both seasons. There were no differences
between tarped and non-tarped plots either in broccoli residue-treated
or control plots. In fumigated plots, propagules declined initially but
later returned to pre-treatment levels by the end of the cropping season.
Continuous cauliflower or fallowing after one cauliflower crop resulted
in stable or increased levels of microsclerotia. Verticillium wilt severity
was lowest in metham sodium-treated plots, followed by broccoli residue-treated
plots and chloropicrin in both years. Plant height, marketable heads,
and head weight were higher in broccoli-
treated than in control plots. These results suggest that broccoli residues
reduce V. dahliae microsclerotia in soil and wilt of cauliflower
as much as or more than chloropicrin and metham sodium, and that rotation
with broccoli may be a feasible approach to manage Verticillium wilt in
cauliflower and other susceptible crops.
Link: http://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS.1999.83.2.124
Xiao, C. L., Subbarao, K. V., Schulbach, K. F., and Koike, S. T. 1998. Effects of Crop Rotation and Irrigation on Verticillium dahliae Microsclerotia in Soil and Wilt in Cauliflower. Phytopathology 88 (10):1046-1055.
Abstract: Experiments were conducted in field plots to evaluate the effects of broccoli residue on population dynamics of Verticillium dahliae in soil and on Verticillium wilt development on cauliflower under furrow and subsurface-drip irrigation and three irrigation regimes in 1994 and 1995. Treatments were a factorial combination of three main plots (broccoli crop grown, harvested, and residue incorporated in V. dahliae-infested plots; no broccoli crop or residue in infested plots; and fumigated control plots), two subplots (furrow and subsurface-drip irrigation), and three sub-subplots (deficit, moderate, and excessive irrigation regimes) arranged in a split-split-plot design with three replications. Soil samples collected at various times were assayed for V. dahliae propagules using the modified Anderson sampler technique. Incidence and severity of Verticillium wilt on cauliflower were assessed at 7- to 10-day intervals beginning a month after cauliflower transplanting and continuing until harvest. Number of propagules in all broccoli plots declined significantly (P < 0.05) after residue incorporation and continued to decline throughout the cauliflower season. The overall reduction in the number of propagules after two broccoli crops was approximately 94%, in contrast to the fivefold increase in the number of propagules in infested main plots without broccoli after two cauliflower crops. Disease incidence and severity were both reduced approximately 50% (P < 0.05) in broccoli treatments compared with no broccoli treatments. Differences between furrow and subsurface drip irrigation were not significant, but incidence and severity were significantly (P < 0.05) lower in the deficit irrigation regime compared with the other two regimes. Abundance of microsclerotia of V. dahliae on cauliflower roots about 8 weeks after cauliflower harvest was significantly (P < 0.05) lower in treatments with broccoli compared with treatments without broccoli. Rotating broccoli with cauliflower and incorporating broccoli residues into the soils is a novel means of managing Verticillium wilt on cauliflower and perhaps on other susceptible crops. This practice would be successful regardless of the irrigation methods or regimes followed on the susceptible crops.
Link: http://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO.1998.88.10.1046
Other Crops
Mazzola, M., Granatstein, D. M., Elfving, D. C., Mullinix, K., and Gu, Y. H. 2002. Cultural management of microbial community structure to enhance growth of apple in replant soils. Phytopathology 92 (12):1363-1366.
Abstract: Apple replant disease typically is managed through pre-plant application of broad-spectrum soil fumigants including methyl bromide. The impending loss or restricted use of soil fumigants and the needs of an expanding organic tree fruit industry necessitate the development of alternative control measures. The microbial community resident in a wheat field soil was shown to suppress components of the microbial complex that incites apple replant disease. Pseudomonas putida was the primary fluorescent pseudomonad recovered from suppressive soil, whereas Pseudomonas fluorescens bv. III was dominant in a conducive soil; the latter developed within 3 years of orchard establishment at the same site. In greenhouse studies, cultivation of wheat in replant orchard soils prior to planting apple suppressed disease development. Disease suppression was induced in a wheat cultivar-specific manner. Wheat cultivars that enhanced apple seedling growth altered the dominant fluorescent pseudo-monad from Pseudomonas fluorescens bv. III to Pseudomonas putida. The microbial community resident in replant orchard soils after growing wheat also was suppressive to an introduced isolate of Rhizoctonia solani anastomosis group 5, which causes root rot of apple. Incorporation of high glucosinolate containing rapeseed (Dwarf Essex) meal also enhanced growth of apple in replant soils through suppression of Rhizoc-tonia spp., Cylindrocarpon spp., and Pratylenchus penetrans. Integration of these methods will require knowledge of the impact of the biofumigant component on the wheat-induced disease-suppressive microbial community. Implementation of these control strategies for management of apple replant disease awaits confirmation from ongoing field validation trials.
Link: http://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO.2002.92.12.1363
Chellemi, D. O. 2002. Nonchemical management of soilborne pests in fresh market vegetable production systems. Phytopathology 92 (12):1367-1372.
Abstract: Nonchemical methods including host resistance, organic amendments, crop rotation, soil solarization, and cultural practices have been used to control soilborne pests in fresh market vegetable production systems. Their suitability as alternatives to methyl bromide will depend on the approach to pest management used by the grower. Traditionally, methyl bromide is used in production systems that rely on the single application of a broad-spectrum biocide to disinfest soils prior to planting. Non-chemical methods are not suitable for a single tactic approach to pest management because they do not provide the same broad spectrum of activity or consistency as fumigation with methyl bromide. Nonchemical methods are compatible with an integrated pest management (IPM) approach, where multiple tactics are used to maintain damage from pests below an economic threshold while minimizing the impact to beneficial organisms. However, adoption of IPM is hindered by the paucity of economically feasible sampling programs and thresholds for soilborne pests and by a reluctance of growers to commit additional resources to the collection and management of biological information. A novel approach to the management of soilborne pests is to design the crop production system to avoid pest outbreaks. Using this “proactive” approach, a tomato production system was developed using strip-tillage into existing bahia-grass pasture. By minimizing inputs and disruption to the pasture, growers were able to reap the rotational benefits of bahiagrass without cultivating the rotational crop. While minimizing the need for interventive procedures, a proactive approach is difficult to integrate into existing crop production systems and will require several years of testing and validation.
Link: http://apsjournals.apsnet.org/doi/pdfplus/10.1094/PHYTO.2002.92.12.1367