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Research - Projects
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Specific Research Projects

 

Preplant soil fumigation in tree, vine, and ornamental nurseries

 

Pacific Area-Wide Pest Management Program for Integrated Methyl Bromide Alternatives

 

Herbicidal weed control in perennial nursery crops

 

Non-chemical weed control

-         Biofumigation

-         Cover cropping

 

Herbicide-resistant weeds

 

Environmental fate of pesticides

 

 

 

 

 

Preplant soil fumigation in tree, vine, and ornamental nurseries

 

Nursery producers of perennial crops including fruit and nut trees, grapevines, and ornamentals in California rely on preplant soil fumigation to meet California Department of Agriculture requirements for nematode-free planting stock.  While nematode control is the primary target pest, weed control is an important secondary target as there are relatively few options for weed control in these high value yet small acreage crops.  My group is part of a diverse research team testing chemical alternatives to methyl bromide as well as improved application techniques to provide adequate pest control efficacy and minimize negative environmental impacts of soil fumigation. 

 

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Preplant fumigation in a nut tree nursery. 

Preplant fumigation in a

nut tree nursery.

 

Weed control in a garden rose nursery fumigation trial.  Fumigated plots left and center, unfumigated plot on right.

 

 

 

 

 

 

 

 

 

 

 

 

 

Pacific Area-Wide Pest Management Program for Integrated Methyl Bromide Alternatives

 

The overall goal of this new areawide pest management program is to foster stable adoptions of economical alternatives to soil fumigation with methyl bromide in agricultural industries served by CUEs for preplant use of the fumigant.  I am the project leader on a multidisciplinary project designed to test pest control efficacy and fumigant emissions with 1,3-dichloropropene applications using various surface treatments in perennial crop nurseries.

 

Click here for more information on ARS areawide pest management programs including the Pacific Area-Wide Pest Management Program.

 

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Herbicidal weed control in perennial nursery crops

 

Weed control in nursery fields of fruit and nut trees, grapevines, and ornamental such as rose bushes rely on preplant fumigation, extensive tillage, and hand labor.  Identification of herbicides and herbicide application techniques that provide effective non-phytotoxic weed control could provide growers an additional tool in their integrated weed management program.

 

 

 

 

 

 

 

 

 

 

Herbicide Screening in a Tree Nursery 

 Herbicide screening in tree nursery:  untreated vs. treated cherry rootstock

 

 

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Non-chemical weed control

 

Intense use of synthetic pest control chemicals do not meet the needs of an increasing number of consumers and growers desiring more sustainable and environmentally conscious pest control options.  Additionally, effective non-chemical strategies could be incorporated into conventionally grown crops to minimize chemical input costs.  We are testing the pest control effects of several organic amendments and cover cropping systems for use in both organic and conventional systems.

 

 

 

 

 

 

 

 

 

 

Biofumigation experiment. 

 Biofumigation experiment.

 

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Cover crop experiment. 

One season of cover crops will be grown between removal of a peach orchard

and replanting a new orchard.

 

 

 

 

 

 

 

 

 

 

Herbicide-resistant weeds

 

The Weed Science Society of America (WSSA) defines herbicide resistance as "the inherited ability of a plant to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type.  In a plant, resistance may be naturally occurring or induced by such techniques as genetic engineering or selection of variants produced by tissue culture or mutagenesis".   In cooperation with University of California scientists and several student interns, we are conducting research to determine the level of resistance and distribution of glyphosate-resistant horseweed (Conyza canadensis) in the San Joaquin Valley of California.  For 2006 glyphosate-resistant horseweed survey map, click here.

 

 

 

 

 

 

 

 

 

 

Horseweed sampling. 

 Horseweed sampling by California State University, Fresno intern.

 

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Environmental fate of pesticides

 

Soil active herbicides can have different levels of persistence and thus, duration of weed control, depending on the herbicide chemistry and environmental factors.  We are studying the rate of degradation of a commonly used herbicide in citrus orchards with various herbicide use histories.  This research may have implications for both selecting appropriate weed control strategies and may affect the potential for off-target movement or environmental contamination with the product.

 

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