- Author: Brooke Jacobs
University of California Cooperative Extension and the Fruit and Nut Research and Information Center are offering the three day extension course, Advances in Pistachio Production, November 18th – 20th, 2014. This extension course sets the standard for UC extension courses with a wide array of farm advisor, specialist and faculty instructors representing decades of experience in California pistachio production. Course topics span the full range of pistachio production including tree biology, orchard establishment, pruning, irrigation, nutrition, pest management, harvest and postharvest.
In addition to lectures covering the essentials of California pistachio production, four new lectures have been added this year to address ‘hot topics' in pistachio production:
- University of California experts will combine a discussion of pistachio biology, with data from new research projects, to present the latest production recommendations for irrigation under saline conditions. Although pistachio is more tolerant of salinity than most tree crops, excess salinity does affect pistachio tree biology and production.
- Everyone knows the feeling of walking into an orchard, or getting last season's grade sheets, and realizing that something is wrong. This is inevitably followed by the question, “How do I fix it?” UC Farm Advisors will provide a new, unique lecture outlining the diagnostic process they use to determine the cause of poor production or tree health.
- Grade sheets are an important tool to measure yield, and understand potential problems in an orchard. UC specialists will review the components of grade sheets in detail, and connect this important postharvest information to future orchard management decisions.
- The success of a pistachio orchard in California is ultimately determined by international markets and exports, even if all other aspects of production are optimal. At the end of the conference experts will present an updated analysis of international markets, and look into the future for pistachio production.
Participants will receive a bound copy of all lecture slides, the recently published Nutrient Deficiency in Pistachio booklet, and exclusive electronic resources.
Advances in Pistachio Production will be held at the Visalia Convention Center on November 18th – 20th, 2014.
Enroll now using our online registration survey: http://ucanr.edu/survey/survey.cfm?surveynumber=13178
- Author: Brooke Jacobs
After an exceptional winter the UC pomology extension community has observed unusual bloom and leaf out patterns in a wide range of tree crops statewide. In general, bloom was delayed with less overlap among varieties within a crop. For example, Bob Beede (Farm Advisor emeritus, Kings County) observed poor overlap in bloom between female Kerman and male Peters pistachio varieties this spring. It is still unclear how much this reduced overlap in bloom timing limited pollination and fruit set.
In addition to reduced overlap in bloom among varieties, researchers in California have reported observations of uneven bloom and leaf out within individual trees. Rachel Elkins (Farm Advisor, Lake and Mendocino Counties), Dr. Bruce Lampinen (UCCE Walnut and Almond Specialist), and Alberto Ramos Luz (visiting doctoral student) have been tracking bloom and leaf out in pear and walnut to measure differences among varieties and understand potential effects on yield and harvest timing in the fall. Lampinen and Elkins observed almost normal bloom and leaf out in north facing buds in both walnut and pear. In contrast, south facing buds in both species were dramatically delayed (up to 6 weeks), dormant, or dead (Pictures 1 and 2). Preliminary measurements taken by Dr. Lampinen's research team at UC Davis indicate that north facing buds may have accumulated more winter chill because they experience substantially lower winter day time temperatures than south facing buds. South facing buds likely had chilling units cancelled by the fogless, sunny winter days in January when the south side of trees was substantially warmer than the north. A cold snap in early December 2013 could have also affected bud viability and provides an additional complicating factor.
Is it possible to say definitively that bloom and leaf out timing observed this spring are due to the low levels of winter chill as measured by the dynamic model?
No. Unfortunately, the biological basis for dormancy and chill accumulation is still poorly understood in tree crops. “The symptoms we've observed this year in many tree crops, including apple, walnut, pear pistachio and prune, are consistent with patterns we've seen in previous warm winters with low chill,” said Dr. Katherine Pope, a UC Davis pomology researcher. “However, without a properly controlled experiment we cannot say for sure whether the symptoms we have seen this spring are a result of low chill.” For now, growers and the UC extension community are continuing to watch and wait to see if this odd spring has any effect on yield at the end of the season.
Additional resources
Fruit and Nut Research and Information Center online chill accumulation models
Kern County newsletters by Bob Beede (Farm Advisor)
January Kings County newsletter
February Kings County newsletter
- Author: Brooke Jacobs
In January 2014 daytime temperatures were unseasonably warm throughout California. Winter temperatures are important because deciduous tree crops (including stone fruit, pome fruit and nuts) require cold during dormancy to bloom and leaf out in the Spring. Although warm January days were followed by more typical cold nights, it is possible that dormant season cold requirements for many California tree crops were not fulfilled this winter.
The first model developed to understand the relationship between cold winter temperatures, dormancy, and rest breaking in deciduous tree crops relied upon simple counts of the number of hours below 45oF during dormancy (chill hour model). Each hour below this threshold was counted as a "chill hour" accumulated, and the number of chill hours required to break dormancy in different species was estimated. Later, the dynamic model was developed to refine estimates of chill requirements in deciduous trees. The dynamic model counts chill accumulation during hours of the day below a temperature threshold. However, warm temperatures occurring later that day can cancel out some of the chill accumulation. According to the dynamic model, warm winter days, like those observed in January 2014, should eliminate any chill accumulated during cold winter nights.
When the traditional chill hour model and the dynamic model are used to calculate chill accumulation at the same weather station the difference between model predictions during the winter of 2013-14 is clear. For example, at the Modesto CIMIS station (#71) the traditional chill hour model estimates that chill accumulation this winter was slightly above average when compared to the previous five winters. However, the dynamic model estimates substantially lower chill accumulation than in previous years (Picture 1).
On Monday I will post a follow-up blog describing abnormal leaf out and bloom patterns we have observed this Spring. Stay tuned!
- Author: Brooke Jacobs
We are getting ready to host our third pomology extension course, “Principles of Fruit and Nut Tree Growth, Cropping and Management”, at UC Davis. Our class is taught by University of California faculty, extension specialists, and farm advisors. The Fruit and Nut Research and Extension Center will provide funding for three scholarships to attend the entire course scheduled on November 10th – 20th, 2014.
A grower who took our first class said that it is a great opportunity to “understand the science behind why we do what we do”, and get “plenty of one-on-one time with the instructors.” Another long time grower from the central valley said that “the instructors are amazing. In this course you learn from some of the top minds in the industry. They're a treasure trove.”
Don't miss your chance to participate!
Scholarship applicants must be California growers who meet at least one of the following criteria:
1) Less than three years of experience growing tree crops
2) In the process of transitioning between crops (ex. peach to almond)
3) Small farms with less than 40 acres of tree crops total
Complete an online application form to apply: LINK HERE
Scholarship applications are due June 1st, 2014. The FNRIC advisory board, composed of UC faculty, extension specialists, and farm advisors, will review applications and notify recipients soon after the deadline. If you have questions about the scholarship application please contact Brooke Jacobs (bsjacobs@ucdavis.edu, 530-754-9708).
- Author: Cheryl Reynolds
- Posted by: Brooke Jacobs
It's cherry growing season and a good time to begin looking for spotted wing drosophila (SWD), Drosophila suzukii. SWD is a small fruit fly that attacks soft-flesh fruit such as cherry, blueberry, raspberry, and blackberry. It first appeared in 2010, and its damage to fruit and increased management costs led to significant economic losses to cherry growers throughout California and the Pacific Northwest.
Unlike other fruit flies that infest rotted fruit, SWD attacks undamaged fruit. As cherry fruit begins to develop and starts to change color from light green to straw, SWD lays its eggs just under the skin of fruit, creating a small scar or a “sting.” One to three larvae may develop inside each cherry, feeding on the fruit and causing it to become brown and soft. Many times SWD flies are not noticed until fruit is mature, and by that time management is not very effective.
Prevention is the key, and one way to prevent damage is to monitor for the pest when it first becomes active. SWD can be monitored with several types of traps partly filled with apple cider vinegar to lure the pest. Monitor traps weekly through the end of harvest, and be sure to confirm the presence of SWD, as other Drosophila spp. may be present in trap catches. SWD males have a single dark spot on the tip of its wing and females have a large ovipositor. See the UC IPM Pest Management Guidelines for identification help and a dichotomous key.
Spotted wing drosophila is still a relatively new pest, and management information continues to change. UCCE Entomology Advisor David Haviland and other researchers have been working to provide what help they can. Haviland has designed a bucket trap called the “Haviland trap” and is working with others to field-test experimental lures for SWD. He's also studying a possible biological control agent. Research has led to new grower guidelines so that early season cherries can be produced and sold internationally. Check out the 2014 Recommendations for Sweet Cherry (PDF).
For management in backyard cherries or other urban areas, see the SWD Pest Note.
For more information about UC IPM's recent work, see the 2013 Annual Report.
