THE SCOOP. on fruits and nuts in Stanislaus County. 8:00-8:30 Registration, coffee, snacks & socializing

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1 University of California Agriculture and Natural Resources November 2011, Vol THE SCOOP on fruits and nuts in Stanislaus County Roger Duncan Pomology & Viticulture Advisor 2011 North San Joaquin Valley Cling Peach Day Sponsored by UC Cooperative Extension & the Cling Peach Board December 13, :30 Noon Stanislaus County Agricultural Center Service and Crows Landing Roads, Modesto 8:00-8:30 Registration, coffee, snacks & socializing Brown Marmorated Stink Bug: A New, Potentially Devastating Pest Maxwell Norton, UCCE Farm Advisor, Merced County Final Wrap Up of Mechanical Blossom Thinner Experiences Roger Duncan, UCCE Farm Advisor, Stanislaus County First Experiences with the Drum Shaker Green Fruit Thinner & Other Mechanical Thinning Tools Eric Spycher & Kevin Voss, Growers Control of Peach Leaf Curl & Other Peach Diseases Dr. Jim Adaskaveg, UCCE Plant Pathologist, UC Riverside Cling Peach Business Meeting - Board Member Nominations: J. D. Allen, Manager, Cling Peach Board Why Sustainability is Important to the Processing Industries Pat McCaa, Pesticide Manager, Del Monte Foods Control of Fleabane & Other Noxious Weeds in Peaches Brad Hanson, UCCE Weed Specialist, UC Davis Regulatory Update for Orchardists Gary Caseri, Stanislaus County Agricultural Commissioner 12:00 - Lunch hosted by the Cling Peach Board 2.5 hrs Continuing Education Units Pending, includes 0.5 hours of laws & regs U.S. Department of Agriculture, University of California, and Stanislaus County Board of Supervisors cooperating 3800 Cornucopia Way, Suite A, Modesto, CA (209) , FAX (209) , - raduncan@ucdavis.edu, website: cestanislaus.ucdavis.edu The University of California prohibits discrimination against or harassment of any person employed by or seeking employment with the University on the basis of race, color, national origin, religion, sex, gender identity, pregnancy (which includes pregnancy, childbirth, and medical conditions related to pregnancy or childbirth), physical or mental disability, medical condition (cancer-related or genetic characteristics), genetic information (including family medical history), ancestry, marital status, age, sexual orientation, citizenship, or service in the uniformed services (as defined by the Uniformed Services Employment and Reemployment Rights Act of 1994: service in the uniformed services includes membership, application for membership, performance of service, application for service, or obligation for service in the uniformed services) or any person in any of its programs activities. University policy also prohibits retaliation against any employee or person seeking employment or any person participating in any of its programs or activities for bringing a complaint of discrimination or harassment pursuant to this policy. This policy is intended to be consistent with the provisions of applicable State and Federal laws. Inquiries regarding the University's equal employment opportunity policies may be directed to Linda Marie Manton, Affirmative Action Contact, University of California, Davis, Agriculture and Natural Resources, One Shields Avenue, Davis, CA 95616, (530)

2 Management of Peach Leaf Curl - New Approaches for an Ever Present Disease Jim Adaskaveg, Janine Hasey and Roger Duncan Peach leaf curl is caused by a yeast-like fungus called Taphrina deformans. The disease may cause significant crop damage and thus, needs to be managed every year. The disease can be especially severe if treatments are not timed properly or when environmental conditions are extremely favorable for disease, such as this last year where six inches of rainfall occurred in November and December. The leaf curl pathogen most likely survives the warm, dry summer period as resistant structures called ascospores. With fall and winter rains, the ascospores germinate and the cells divide and multiply like yeast. These prolific spores may completely cover twigs and buds of peach trees, as well as the space between bud scales as populations increase. Tree to tree spread of the fungus occurs in two ways: by dissemination of yeast-like spores via splashing water and by ascospores that are forcibly discharged and thus, are air-borne and can move longer distances. Leaves and the occasional fruit infections occur only on young or undifferentiated tissue by the parasitic stage of the parasite. Cool, wet weather during leaf emergence favors disease development. Historically, copper has been the stand-by treatment for managing this disease. For diseases like peach leaf curl that need to be controlled over extended periods of wetness, most copper products with their long residual activity have worked well over the years. Recently, formulations of fixed coppers have been developed with reduced metallic copper equivalent (MCE). For diseases like peach leaf curl that need residual activity, the efficacy of these products when used at lower rates have not been as efficacious over long, rainy winter seasons. If using the newer reduced MCE copper products, always use the upper label rate, consider using a sticker or winter oil as an adjuvant to increase persistence, and plan to make two applications. Because of increased costs of copper products and the need to prevent over-usage of copper in agricultural ecosystems, we have recently identified several products that are equivalent or even more effective than copper for managing peach leaf curl. Products such as ziram, chlorothalonil (e.g., Bravo, Chlorothalonil, Echo, Equus) and dodine (Syllit) when applied at optimal timings are effective treatments. Overall, ziram has been most effective. The long residual activity of ziram and chlorothalonil is a needed characteristic for managing the disease with minimal (one or two) late fall or winter applications. In years with high rainfall in late fall and winter, higher rates and at least two applications of these materials should be used. The first should be applied in late November / early December and the second in January / early February. Under low rainfall conditions during the winter period, a single late-nov./early-dec. application of ziram has been very effective in our trials. Different strategies have been implemented for managing leaf curl. Some product labels indicate only bud swell or pre-bloom applications, whereas others indicate dormant (late Nov./early Dec.) and delayed dormant (Jan./early Feb.) treatments. For all the products that we evaluated in California, the pre-bloom application is the least effective timing after a wet winter. The most effective timings are the late Nov./early Dec. followed by the Jan./early Feb. application. Both are important during wet winters. The goal of these timings is to prevent high inoculum populations from developing on tree surfaces that allow bud infestation and subsequently early infection of developing leaves. The use of only pre-bloom treatments allows for high populations to develop during tree dormancy and thus, populations cannot be reduced to low levels that allow highly effective disease control. Optimizing strategies for peach leaf curl management in orchards with a history of disease: Apply a late Nov./early Dec. treatment after most leaves have fallen from trees to ensure excellent coverage of branches, stems, and buds. (This spray will also control shot hole). Apply the late Nov./early Dec. treatment before significant fall and winter rainfall occurs. Apply an additional Jan./early Feb. treatment if high rainfall occurs in Dec. and early Jan. In addition to Jan./early Feb. treatments,

3 apply a pre-bloom (bud swell or two weeks before bloom) treatment if high rainfall occurs in Feb. Order of importance of applications: dormant (late Nov./early Dec. ) > delayed dormant (Jan./early Feb) > pre-bloom (two weeks before bloom) for environments favorable for disease. Apply treatments at a minimum of 100 gals/a. Higher gallonage ( gals/a) generally improves coverage. Use an adjuvant such as oil or a sticker to increase persistence. Use higher labeled rates of new formulations of copper products (e.g., minimum of 3-4 lbs MCE/A/application) to increase effective residues that are toxic to the pathogen. For ziram, use 6-8 lbs/a for long-range forecasts of high precipitation and a minimum of 4-6 lbs/a for drier forecasts under California conditions. For chlorothalonil and dodine, plan to make at least two applications in northern peach production areas of California where higher rainfall occurs. A single application may be sufficient in southern peach growing districts of California. Herbicide-Resistant Weeds in California Tree and Vine Crops - Manager Perception Survey Brad Hanson; UC Davis Cooperative Extension Weed Specialist Purpose of the Survey: The goal of this survey is to determine grower, applicator, and pest control advisor perceptions and experiences related to herbicide-resistant weeds in perennial cropping systems. This research is being conducted as a part of a larger project (Evolution and Management of Herbicide Resistant Weeds) which involves several UC Davis, UC Cooperative Extension, and Fresno State University faculty. Methods: We will conduct a survey of at least 1,000 weed managers who work in California orchards and vineyards. In late 2010 and early 2011 we used a series of in-person surveys at grower meetings. To expand upon that technique, we developed this web-based survey which has a similar format and will be open from June 2011 through February Participation is voluntary, all data will be collected anonymously, and no personally identifying information will be kept or shared. The survey, which should only a few minutes to complete, includes a series of simple questions to gauge: 1. Demographics (respondent farming system, approximate acreage, and region) 2. Weed control practices used 3. Experience and concerns with herbicide resistant weeds Impact on Weed Management: Once complete, the results of the survey will be presented to scientific and extension audiences and will be used to help develop future research directions and extension education programs to benefit growers and pest managers. Compared to annual cropping systems in other parts of the country, there has been very little research on understanding the production impacts, economic consequences, or management changes imposed by herbicide resistant weeds in the unique perennial cropping systems in California. Drawing for Weed and Crop Production Books After the survey is completed in February 2012, we will draw the names of 15 participants to receive their choice of several UC Publications related to weeds, integrated pest management, or tree and vine crop production. These high quality publications are pages and usually are sold for $ To participate in the drawing after completing the survey, you will have the option to go to another webpage where you can enter your name and contact information for the drawing as well as your preferred UC book. This information will not be directly associated with the survey responses to preserve anonymity. The survey is online at:

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6 Save the Date! 2011 North San Joaquin Valley Cling Peach Day Sponsored by UC Cooperative Extension & the Cling Peach Board December 13, :30 Noon Stanislaus County Agricultural Center Service and Crows Landing Roads, Modesto North San Joaquin Valley Almond Day February 1, 2012 Martin Petersen Event Center th Street, Modesto New Publications Available NEW LOCATION!! Small Farms Handbook, 2nd edition Organic Winegrowing Manual Sample costs to establish an orchard and produce almonds (flood & microsprinkler) Sample costs to establish an orchard and produce processing peaches Cost studies can be purchased from our office for $1.00 each or downloaded for no charge at UNIVERSITY OF CALIFORNIA COOPERATIVE EXTENSION 3800 Cornucopia Way, Suite A Modesto, CA NONPROFIT ORG. US POSTAGE PAID MODESTO, CA PERMIT NO. 400 The Scoop on Fruits & Nuts In Stanislaus County November 2011 CURRENT RESIDENT OR