Dear Master Gardeners, 

As many of you know, I retired at the end of June.  During my 34 years with the University of California division of Agriculture and Natural Resources (UC ANR), many of my most rewarding moments have been spent with Master Gardeners.  I am constantly amazed by the enthusiasm, energy, creativity and knowledge of Master Gardeners. What an incredible service they provide for UC and the California public!

I was hired to create Integrated Pest Management (IPM) programs for agriculture, but my interest in Master Gardeners started early.  I remember attending the California State Fair in the early 1980's and being somewhat horrified to find the UC Master Gardeners answering questions using the Ortho Problem Solver and the Rodale Guide to Organic Gardening.  I was told that they relied on these books because UC provided very little garden pest management information.   This motivated me to write Pests of the Garden and Small Farm and later to hire Steve Dreistadt to compile Pests of Landscape Trees and Shrubs.  From there we moved on to the Pest Notes, Quick Tips, UC IPM web site, UC IPM kiosk, our YouTube channel, blog and Twitter. Master Gardeners embraced and promoted all these products and now UCIPM is as well known for its home and garden information as for agricultural IPM.

I have loved teaching Master Gardener volunteers.  They are the most enthusiastic students ever.  I learn something every single time I go out and teach a class—and I've taught thousands of them.  UC Master Gardeners inspire so much of what we do.

For example, it was Master Gardeners who stimulated our research on convergent lady
beetle releases for aphid control.  All the published literature said releases weren't useful, but Master Gardeners challenged this idea. Over a 3-year study, Steve Dreistadt and I found that they were right, and we published several journal articles documenting the results. 

Last but not least, thank you to all of you Master Gardener Coordinators. Each of you does an incredible job gently guiding and informing your enthusiastic volunteers.  I have watched you in action and you do something special every day.

Sincerely,

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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.

 

Firewood Task Force

Memorial Day weekend, traditionally considered the beginning of California's camping season, is right around the corner.   If you are preparing for an upcoming trip, keep in mind that you can help protect California's forests by buying firewood from a local source near the campsite rather than bringing it with you.  

When people move wood from place to place, they may also be moving invasive insects and diseases that threaten California's landscape and wildland trees. The goldspotted oak borer, which is devastating native oaks in San Diego, was likely brought there from Arizona in firewood. The polyphagous shothole borer, walnut twig beetle and thousand cankers disease, and the pathogen causing sudden oak disease, all continue to spread to new areas on infested wood chips, plant debris, or wood moved for woodworking or firewood.

Over the past year, the California Firewood Task Force has asked the public to "buy it where you burn it"—that is, don't bring wood from home when you camp, do use wood from local sources, and leave leftover wood at the campsite for the next camper.  Even if wood does not appear to have borer holes or other evidence of pests, don't assume that the wood is pest free.  Be on the safe side and don't move it. 

The California Forest Pest Council established the Task Force in 2011 to educate Californians about what they can do to prevent movement of invasive pests in wood. The Task Force developed a Web site, put up billboards across California, sponsored children's activities at parks and fairs, encouraged campgrounds to sell only local firewood, gave presentations across the state, and developed best management practices, posters, and other information to engage the public.

For more information visit www.firewood.ca.gov

 

 

One of California's most adored flowering plants, impatiens, is being threatened by a serious pest. You may have noticed the common garden impatiens missing from nurseries, retail store shelves, and landscapes, parks, and gardens this year.

Impatiens are dying from a relatively new plant disease called impatiens downy mildew, caused by the fungus-like, oomycete pathogen Plasmopara obducens. The pathogen primarily affects varieties of Impatiens walleriana, or hybrids with an I. walleriana parent and wild impatiens (I. balsamina). Note that this pathogen does not affect New Guinea impatiens (Impatiens hawkeri) or other bedding plant genera. This disease develops rapidly, with a few leaves on apparently healthy impatiens beginning to show slight yellowing and stunting followed by development of white, powdery spores on the undersides of leaves, and later, by leaf and flower drop. Plants are likely to become completely defoliated within several weeks. The pathogen produces airborne spores, which can travel for many miles, as well as swimming zoospores and oospores, which can survive within soil and plant debris for long periods and infect healthy plants when replanted in the same area.

Early detection is especially critical for this disease since chemical control has been shown to be ineffective once sporulation begins.  Scout routinely to identify and remove diseased plants before epidemics can result. Removing infected plants may limit spread to other areas of the landscape.

Consider growing alternative bedding plants that will grow well in shady areas of the landscape but that will not be affected by the disease.  Some examples include Bergenia hybrids, Caladiums, Coral bells, Lobelia, New Guinea impatiens, Sweet alyssum, and wax begonias. 

This article was originally published in the December 2013 issue of the UC IPM Green Bulletin.