California Gardening Blog
We'll be in Davis on April 13th, in Los Angeles on May 17th and in Riverside on May 18th.
Registration is only $20 (includes lunch)!
Learn more and register here: http://ccuh.ucdavis.edu/events/citrus/citrus.
Workshop includes information about grafting, pruning, varieties, and pest management.
See you there!
Reprinted with permission from David Haviland. Originally posted on February 8, 2013.
For the last few years citrus growers in the San Joaquin Valley have been nervously watching the establishment of Asian citrus psyllid in southern California and bracing themselves for the day of northward movement. That day arrived in November 2012 when two psyllids (Strathmore 16 Nov. and Terra Bella 21 Nov.) were caught on yellow sticky card traps, in addition to a third capture back in January 2012. These captures have now resulted in restrictions on the movement of citrus in the heart of California's principal citrus production region.
Asian citrus psyllid is a small insect the size of an aphid that feeds on citrus leaves and stems. It is the vector of a deadly bacterial disease of citrus called huanglongbing, often referred to as HLB or citrus greening. This pest and disease combo has resulted in devastating losses to the citrus industry in Florida, and has the potential to have a similar affect in California.
Prior to November 2012 Asian citrus psyllid had been reported in eight California Counties, mostly in the southern part of the state, with a combined total of approximately 26,000 square miles under quarantine. However, the two finds in Tulare County mark the first time the psyllid has been found in the heart of California's principal citrus production region of the lower San Joaquin Valley: Kern, Tulare and Fresno counties produce over 200,000 acres of citrus at an annual value of approximately $1.7 billion.
The capture of individual psyllids on sticky traps in Strathmore and Terra Bella gives CDFA the authority to establish a quarantine of citrus within a 20-mile radius of the find in Strathmore. Prior to doing this, however, CDFA has opted as an interim step to only regulate citrus in a 5-mile radius around each find until further trapping and delineation can determine if psyllids are truly established in the region, or if the psyllids caught were just non-breeding hitchhikers brought to the corridor along State Highway 65 from infested counties in Southern California. If further delineation detects an established population it is anticipated that quarantines would be established. If established, a quarantine for Asian citrus psyllid would last a period of 2 years since the most recent capture. If additional psyllids were captured during the two-year quarantine the clock would reset itself for another two years.
Due to the fact that the psyllid only feeds on leaves and stems (and not fruit), citrus growers within quarantine zones in California have several options for harvesting and shipping fruit. Fruit harvested within quarantine zones can be picked, transported and packed within the quarantine zone without restrictions. Once clean fruit is packed (no leaves or stems) it can be shipped to locations outside of the quarantine.
Packing fruit from within the quarantine at packing houses outside of the quarantine is also possible under a CDFA compliance agreement that can be accessed through the County Agricultural Commissioner. These agreements state that the grower is willing to comply with CDFA and USDA regulations regarding the movement of bulk citrus, the most important of which is that bulk citrus must be processed through trash-removal equipment (to remove all leaves and stems) before it is shipped in bulk to a packer outside of the quarantine.
The Asian citrus psyllid quarantine also affects retail nursery stock. Currently there are compliance agreements and protocols available that allow retail nursery stock to be moved within the quarantine zone. However, no provisions are currently available to move nursery stock from the quarantine zone to regions outside of the quarantine zone unless the plants were budded and produced within a federally-approved screenhouse facility.
Regulations regarding Asian citrus psyllid can change quickly. For that reason citrus growers are encouraged to maintain good contact with their local Agricultural Commissioner. Additional information on the status of quarantines and other restrictions can be found online at
Citrus Greening Disease has been moving through California. We are reaching out to California gardeners and UC Master Gardeners in an effort to slow the spread.
How can you learn more or help?
- Watch the California Garden Web for posts related to Asian Citrus Psyllid and Citrus Greening caused by the bacteria known as Huanglongbing.
- Help us spread the word by following us on Twitter at @ACPoutreach.
- Attend a talk on Citrus Greening near you! We'll post events here.
- Learn more at http://www.californiacitrusthreat.org/.
We have just gone through a couple of weeks of over 100F in northern California on top of being inundated by smoke from all of the wildfires in the mountains surrounding the Sacramento Valley. Nonetheless it really is time to think about that fall vegetable garden. We call this the cool season garden because the plants tolerate colder temperatures...not that they need cold temperatures to grow. Getting your cool season vegetables in this time of year ensures that they grow to an adequate size before the soil temperatures cool to the point that they stop growing until spring. Your plants will be large by the time they come into the harvest period in early to late spring. Some of the things that I intend on planting in the next few weeks include kale, fennel, spinach, Swiss chard, beets, carrots, kohlrabi, leeks, lettuces and turnips. Notice I did not include broccoli, cauliflower, Brussels sprouts or cabbage. The reason is that I have become so frustrated with the pest problems associated with them. The cabbage aphids, and cabbage loppers make these crops a pain....both pests are persistent little buggers and to try and be an organic gardener and manage them -well it isn't worth it to me. Besides that, they are usually so cheap to buy in the market at any time of the year. The rest of the crops tend to be more pest free and they are generally more expensive to purchase in the market and, most importantly, I love these crops.
Of the varieties that I recommend, for kale, I love the “Winterbor” curled varieties. You do have to watch the curled types carefully though for any aphids. Once they get inside the curly leaves, it is really tough to get them under control. I also love the smooth Georgia-type hybrid with savoyed leaf called “Top Bunch”.
Of the spinach varieties, while each seed company might each have their own name, I think the best for the Northern California area is a slow bolting savoy type. Johnnies Selected Seeds has several but “Tyee” is the one that I buy. I am going to plant extra of this because one of my friends husband has cancer. He feels that spinach greens with their high level of antioxidant helps to support his immune system and fights the cancer in his body.
Of the chards, “Rainbow” is just beautiful both in the garden and on the table. The color will generally cook out of them but while in the garden they are just lovely.
I have the best luck with mixed lettuces harvested as baby leaves rather than head lettuce. All types do well if harvested often. I also like to plant some radicchio because it is so darn expensive to buy and is great to use in salads for color and taste.
I am going to plant a variety of carrot good for overwintering in the ground called “Napoli”. The beet variety for me is “Merlin” (a dark red) and a Chioggia type that has the beautiful interior striping.
So, if you want a low work garden this winter into spring-start now! Remember, you don’t need an official vegetable “garden” to grow edibles. You can incorporate many of these crops into your annual flower beds, a garden box on the balcony, or in a sunny spot off of the patio. For more ideas on growing vegetables visit with your local Master Gardener Volunteers. To find the Master Gardeners in your county go to: http://camastergardeners.ucdavis.edu/
And for more vegetable growing information go to the California Garden Web
This year was a tough year for the peaches and nectarines. It seemed that even though we sprayed with a copper oil spray and with a registered fungicide at the right time, the PLC was very noticeable on the trees this spring. Treating now is useless as is pulling off the infected leaves. Never the less, many peolple do it because it makes them feel better and they don't see the infected leaves anymore. Chuck Ingels on the other hand is trying to do something about it! He has been working on methods that home gardeners may use to thwart PCL without the use of the chemical recently removed from sale to home gardeners, specifically Lime Sulfur and Copper Fungicide Microcop. The only fungicide products left for treating peach leaf curl are those containing lower levels of copper (such as Liqui-Cop), copper soap, and the non-copper synthetic fungicide chlorothalonil. Because the level of copper is quite low in these products they are not as effective as Microcop was. Chuck conducted the trial at the Fair Oaks Horticulture Center demonstration orchard (and one tree in a private yard) to determine what works best for controlling peach leaf curl now that the most effective products are no longer available.
The treatments that Chuck used included: Lime sulfur, Liquicop, Concern Copper Soap Plus Oil, Agribon medium weight row cover fabric, Agribon plus Liquicop, Kelp Extract
The results: Compared to untreated branches, those treated with Liqui-Cop averaged about 70% control, copper soap 80% control, and Agribon by itself just under 60% control, but these treatments were not statistically different. Agribon generally kept the branches dry, although some moisture was evident after heavy rains. Two treatments provided nearly complete control: (1) Agribon plus Liqui-Cop, and (2) lime sulfur (late fall) followed by Microcop (late winter). Maxicrop (kelp) did not work at all and substantially increased the severity on some of the branches.
The two liquid copper products have fairly similar efficacy—they improved control and perhaps sufficiently, but still not great. The control achieved, although resulting in some unsightly damage, is probably enough to allow the tree to produce good shoot growth with enough healthy leaves to nourish the rapidly growing young fruit. Agribon likely allowed some rain to penetrate to the branches. It may be best held up with a post in the middle to allow rain to run off down the sloped sides rather than having a flat surface on top, but it must be fastened securely because of strong winds. Agribon plus Liqui-Cop worked quite well, probably because the fairly good control with Liqui-Cop was enhanced by drier conditions. The combination of lime sulfur (in late fall) followed by Microcop (in late winter) was highly effective, as expected. Normally only one of these products was used for both fall and winter applications, but insufficient product was available for both. Maxicrop (kelp), even sprayed eight times, provided no control at all.
For more details on Chuck Ingels Peach Leaf Curl Trials, go to the Sacramento County Website at: http://cesacramento.ucdavis.edu/Pomology/____Tree_Fruit_Crops/2012_Peach_Leaf_Curl_Trial_at_the_Fair_Oaks_Horticulture_Center/