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. 

Caution! 

Don't miss this opportunity to add money to your UCCE Master Gardener Program's bank account. That's right, the MarketPlace can help volunteers increase the flow of money into their program's operating budget.

The passion UCCE Master Gardeners have for sharing horticulture with the community is fueled by our love for people and love of plants (or maybe you prefer insects).  Regardless of the motivation that brings you to the UCCE Master Gardener program, we all have one thing in common - we must periodically purchase items for our gardens! 

Historically, conference attendees arrive with empty suitcase space specifically intended for transporting home newly acquired treasures.  The MarketPlace is an opportunity to collect unique gardening items while helping individual counties along the way.  

Each county has the opportunity to reserve a sales booth space, provide sales materials of their choice and volunteer to assist with store operations.  Funds raised by each individual county will be returned to them less minimal operating costs.

Within the next month each UCCE Master Gardener Coordinator will receive an information packet with preliminary participant guidelines. Space may be limited, so keep an eye on the 2014 UC Master Gardener Conference website or the statewide blog for MarketPlace updates.  Absolutely, don't allow the information packets to lay dormant or become part of the compost pile. 

Start the conversation in your county today, be prepared to respond quickly when the packets arrive in the mail.  Talk about how your county can capitalize by participating in the MarketPlace. Brainstorm about what ‘must-have' items will motivate gardeners, naturalists, or bird watchers to part with their hard earned cash. Think about display methods for showcasing your sales items.  Offer to coordinate your MarketPlace booth or be a committee participant. Be the one who makes a difference!

Yolo and Sacramento counties are proud to be hosting the 2014 MarketPlace. We look forward to having you join us in Yosemite, one of California's most treasured spots!

Happy Holidays to All!

This Thanksgiving I finished up my bulb planting project and reflected on all of the things I am grateful for.  If you’ll indulge me - I’d like to share a few of them with all of you.

1. I am thrilled to be a part of the UCCE Master Gardener community and am still reveling in the warm welcome, patience and support as I have been making the transition.
2. New staff and positions at the statewide office will help us better address the needs of the UCCE Master Gardeners! Aubrey Bray is enjoying her new position as training coordinator. Aubrey is doing the formative work for online training modules to complement the CA Master Gardener Handbook (new handbook’s ETA is fall 2014).  Melissa Womack is settling is as program coordinator and has already shown us how valuable her talents will be to harness the power of our Web based assets throughout the state. 
3. The University of California Agriculture and Natural Resources (UC ANR) has a beautiful new home. Now all programs and functions within UC ANR are housed in the same building in Davis, Calif. The statewide Master Gardener office moved in early November, and now has direct access to Integrated Pest Management (IPM), Information Technology (IT) and increased visibility to ANR leadership!

Here is our new contact information:

Master Gardener Program

University of California, Agriculture and Natural Resources

2801 Second Street

Davis, CA 95618-7779

Main:530.750.1362

Fax: 530.756.1076

 

Melissa: 530.750.1388

Aubrey: 530.865.1105

Missy: 530.750.1266

 

I am looking forward to a fruitful 2014 with exciting opportunities, including the 2014 Statewide Master Gardener Conference next October.  Please keep your eyes open for blog posts and updates – the theme is appropriately Growing Together, a tagline we are actively putting into practice now and for years to come.

Wishing you a safe and family filled holiday season!

Warm Regards,

Missy

I love the taste of summer. For me the taste of summer is that first charcoal-grilled hot dog of the season, sun brewed iced tea, and the big bowl of slightly chilled cherries that is always present at summer BBQs.  If you are about to start collecting your summer bounty of beautiful, red ripe cherries be aware that this year might not be the bumper crop you expected due to one pesky little problem.

Adult male spotted wing drosophila. Photo courtesy UC IPM.

Spotted wing drosophila (SWD), Drosophila suzukii, is a fruit fly that infests soft-fleshed fruit such as cherries, raspberries, blackberries, blueberries, and strawberries. A native of Japan, SWD found its way to California in 2008 and has been giving commercial and home gardening operations problems ever since. Unlike its relatives, SWD attacks fruit as it ripens as well as damaged or overripe fruit. This is due to the female’s serrated ovipositor that allows her to literally saw into healthy, intact fruit to lay eggs. Females oviposit or “sting” healthy ripening fruit and deposit 1-3 eggs per sting site, and can go on to sting many more times. Eggs hatch and grow into maggots that feed on the fruit, turning it brown and soft.

Bill Krueger, Farm Advisor and County Director for Glenn County Cooperative Extension, found SWD on his cherries this week. He identified the pest on an early-ripening variety, but hopes he’ll be able to protect his second variety that ripens a little later. He's lucky to have caught it, as most backyard gardeners won't see the microscopic punctures or other signs of SWD until it is too late.

Because SWD infest healthy fruit it is essential to identify early and take appropriate measures. Waiting until harvest to spray or take other measures will not be of any use because maggots are already in the fruit. Some management options highlighted in “Pest Notes” a publication of the UC Statewide Integrated Pest Management System Program, include: securing a fine mesh netting over whole plants pre-ripening to exclude adult females, early harvest to reduce exposure, and spraying organic insecticide spinosad (“Monterey Garden Insect Spray”) 2-3 weeks before harvest just as fruit turns from yellow to pink. Another application may be needed 7-10 days later.

SWD larva on damaged cherry. Photo courtesy UC IPM.

For more information about SWD identification and management options see the UC IPM Pest Notes.