This research was conducted in the Giannini Postharvest Laboratory at the UC Kearney Agricultural research and Extension Center. In celebration of this work, and its positive effects on the California stone fruit industry, Dr. Crisosto recently hosted a tour of KARE for twenty two produce executives and supervisors from the SaveMart Corporation.

For more details about the event follow the Kearney Agricultural Research and Extension Center blog.

A team of UC Cooperative Extension Farm Advisors recently developed a new, free guide to using a pressure chamber for irrigation management in walnut, almond and prune. The new guide, “Using the Pressure Chamber for Irrigation Management in Walnut, Almond, and Prune”, includes clear and concise descriptions of every aspect of pressure chamber operation and interpretation including:

• Explanation of tree water use physiology and how a pressure chamber works
• Descriptions of specific features of different pressure chambers commonly used by growers
• Instructions on how to take measurements in young and mature orchards
• Target stem water potential (SWP) values with explanations and data from UC research programs
• An explanation of the SWP “baseline” and a guide to using baseline values and SWP measurements to schedule irrigation
• Effects of over- and under- irrigation on yield, quality, and disease susceptibility

High quality figures and images accompany each set of instructions on how to use a pressure chamber, interpret your results, and schedule irrigation to optimize yield. This invaluable guide is available for download in pdf format FREE from UC Agriculture and Natural Resources website. To get your free copy click HERE.

Authors:

Allan Fulton, UC Cooperative Extension Irrigation and Water Resources Advisor, Tehama County

Joe Grant, UC Cooperative Extension Farm Advisor, San Joaquin County

Richard Buchner, UC Cooperative Extension Farm Advisor, Tehama County

Joe Connell, UC Cooperative Extension Farm Advisor, Butte County

The Fruit and Nut Research and Information Center is organizing a two day international meeting, Understanding and Preparing for the Threat of Plum Pox Virus Spreading to California and the Western States, to address a new threat to the U.S. stone fruit industry, Plum Pox Virus (PPV, aka sharka disease). The meeting will be held in Giedt Hall on the UC Davis campus on September 29^th and 30^th, 2014.

Click HERE for more information and online registration

Plum Pox Virus is an exotic invasive pathogen spread by aphids which infects Prunus tree crops (including plum, prune, cherry, almond, peach and apricot). The virus compromises tree health, causes premature fruit drop (Picture 1), and reduces fruit quality (Pictures 2). Infected fruit is not suitable for fresh market and most processed products.

Plum pox virus was identified in Europe in the early 20^th century, and has rapidly spread world-wide since the late 1980s, likely due to the globalization of trade and travel. PPV is now present in all major fruit growing countries except the U.S., Australia, New Zealand, and South Africa. The central valleys of California are particularly vulnerable to this threat because of the high concentration of Prunus crops, and a lack of geographical barriers to the spread of the disease by insects.

The upcoming meeting is open to all members of the stone fruit industry interested in learning more about the threat posed by PPV, and the development of measures to manage the disease in California.

The goals of this meeting include:

• Update on the status and spread of PPV worldwide
• Exchange ideas for strategies to be used in the event that PPV is introduced in California and the Western US
• Promote awareness of educational and extension tools to provide information about the threat of PPV and its potential spread in the US
• Identify research programs that could minimize the threat of PPV to the US stone fruit industry.
• Develop a response plan for PPV outbreak in California.
• Explore funding opportunities to support projects and actions identified during the conference.

Source of images:

L. Levy, V. Damsteegt, R. Scorza, and M. Kolber. 2000. Plum Pox Potyvirus Disease of Stone Fruits. APSnet Features Accessed June 16, 2014

https://www.apsnet.org/publications/apsnetfeatures/Pages/PlumPoxPotyvirus.aspx

Summer is upon us, and nothing quite says summer more than eating freshly picked blueberries or using them in delicious desserts. California blueberry growers can find an additional treat – the newly published UC IPM Pest Management Guidelines for blueberry on the UC IPM web site. California is quickly becoming a top producer of blueberries, and the new guidelines can help with management information on blueberry pests such as thrips, light brown apple moth, and spotted wing drosophila with additional information on pesticides and resistance.

It may be hard to believe but as of 1996, blueberry production was limited to colder states like Washington, Michigan, New Jersey, and Oregon, where naturally acidic soils and winter climates suit the traditional highbush varieties. As recently as 1997, California blueberries were only growing on less than 200 acres across the state. According to the latest CDFA statistics, 2012 continued to show what has been an increasing trend for California blueberries, with more than 40 million pounds harvested, $133 million sold, and plantings in more than 4,700 acres spanning San Joaquin, Tulare, Kern, Ventura, and Fresno counties.

In 1995 the University of California Small Farms Program and cooperating farmers started evaluating low-chill southern highbush varieties in San Luis Obispo and Ventura counties. They found that “low-chill” southern highbush varieties offered the most promise for extended season production on the central coast. By 1997, Kearney Agricultural Center trials found that southern highbush cultivars were also well adapted to the semiarid climate of the San Joaquin Valley. Further evaluations identified the best yielding and flavorful cultivars. Initial and ongoing UC Small Farms studies have escalated California blueberry production swiftly up the learning curve, providing California farmers of small to moderate operations a niche in a very competitive market.

Today, California blueberries are harvested from May through July in the San Joaquin Valley and January through May on the central coast. While consumer demands are on the rise and profits can be excellent, producing and harvesting blueberries in California is expensive. It can run over $10,000 per acre to prepare a field because successful cultivation in many areas necessitates soil and irrigation water acidification and adding tons of mulch per acre. Specialized equipment, labor-intensive pruning, and pests like light brown apple moth, thrips, and spotted wing drosophila can add substantially to cost. Therefore, getting the right information and planning is imperative. While the UC Small Farms Program continues to develop field and market research for blueberry production in California, growers can also turn to the newly published Pest Management Guidelines for blueberries.