Calls have come in – “What is the browning on the avocado leaves? Thrips damage? Salt damage? Dothiorella?” Nope, Frost Damage. From the end of February to the first week of March, Santa Paula had one night of 30 deg F, and 3 nights of 33 and a few nights around 35.. It wasn’t cold cold, but cold enough that there was damage to the avocados there and more so the further east and up toward Ojai.It wasn’t enough to defoliate the trees, although many were under stress from the flowering that is going on and a lot of the leaves were dropping from the flowering stress. The damage to the leaves is a darkening of the leaf both of the bottom surfaces. In many cases, the flower panicles got scorched. This is just the start of a big flower push and it looks like there’s a lot of flowers that have not pushed that will be fine. It could still be a good avocado year. The coffee really got roasted. — By Ben Faber, UC Cooperative Extension
Tag: UC Cooperative Extension
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Growers Experience Minor Frost Damage on SO CAL Avocados
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Characteristics of New Walnut Rootstocks Growers Should Consider
While walnut growers tend to pay more attention to walnut prices and varieties, rootstock selection can make a big difference in the establishment and longevity of their orchards. Watch this brief interview with UCCE Orchard Systems Advisor Luke Milliron as he shares characteristics and availability of new rootstocks for the walnut industry. Read more about in Pacific Nut Producer Magazine.Please thank this video’s sponsor Trece for their industry support. -
Sacramento Valley Processing Tomato Production Meeting, Feb. 10
The UC Cooperative Extension (Colusa, Sutter, Yuba, Yolo, Solano & Sacramento Counties) invites growers to attend the 2022 Sacramento Valley Processing Tomato Production Meeting virtually (Zoom) on February 10th from 9:00-11:40 a.m. DPR and CCA Continuing Education Credits have been requested. Registration is free and can be done online HERE. Some of the topics of discussion will include: broomrape biology & management, automation with mechanical in-row cultivators for conventional processing tomatoes, root knot nematode management, and the unusual outbreak of beet curly top in 2021. Click HERE to see the full agenda.
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Evie Smith, New UCCE Staff Research Associate in Orchard Crop Systems
Have you had a chance to meet Evie Smith, one of our new Staff Research Associates with the UC Cooperative Extension? Watch her brief introduction here to learn about her and the almond, walnut and prune projects she is working on with Sacramento Valley farm advisors.Please thank this video’s sponsor Suterra for their industry support. -
USAID Awards UC Davis $15 Million for Global Horticulture Research Program
The U.S. Agency for International Development will provide a base $15 million investment over the next five years, with up to $34.5 million total funding possible, to support a global research program led by the University of California, Davis, that advances fruit and vegetable production, handling, and consumption.
The Feed the Future Innovation Lab for Horticulture will work with and promote local leadership in communities across the globe to advance horticultural and social innovations for nutritional and financial security. This competitive five-year program was first awarded to UC Davis in 2009 and renewed in 2014.
“Horticulture offers big health, economic and environmental benefits,” said Elizabeth Mitcham, program director and a UC Cooperative Extension specialist in the Department of Plant Sciences. “UC Davis will be leading an outstanding global consortium that will be able to make big impacts on developing sustainable, local expertise and innovative technical and social solutions to empower horticulture producers and their communities.”
UC Davis will be joined in a consortium with Florida A&M University, Michigan State University, Texas A&M, and World Vegetable Center, along with subject matter experts from Penn State University and Making Cents International, to help manage this program.
The Horticulture Innovation Lab will focus their efforts in West Africa, East Africa, South/Southeast Asia and Central America. At the forefront of their research will be the development of environmentally sustainable, market-oriented production and post-harvest handling methods that provide smallholder farmers and other stakeholders in fruit and vegetable value chains more income, as well as improved access to fruits and vegetables to better nourish their families and communities.
Locally led, globally supported
Within the UC Davis-led consortium are partners and specialists with expertise in horticulture, agronomics, agri-sociology, agribusiness and agri-policy. The Horticulture Innovation Lab will convene these global, regional and local experts to determine research needs in each geographical area. Once these research needs are defined, the team will emphasize a holistic, locally led approach to build community resilience and to support inclusivity.
“We asked ourselves, ‘how do you effect change in a system now that overcomes immediate challenges and those yet to present themselves?’” said Erin McGuire, associate director of the Horticulture Innovation Lab. “We need to understand the implications of our projects and to work closely with local leaders and community members to ensure a pipeline of appropriate innovations now and in the future.”
Building on fertile grounds
Fruits and vegetables provide vital nutrients for healthy communities, empower women and youth, and improve overall sustainability in production systems — this was the central tenet informing all of the work that the Horticulture Innovation Lab did during its first 10 years.
As a direct result of the Horticulture Innovation Lab’s work, more than 750 horticultural technologies are now available for transfer and scaling in communities across the globe. More than 32,000 farmers are applying or using these technologies as a result of the lab and its network’s collective work, and more than 13,000 hectares of land are under new management practices.
The Horticulture Innovation Lab produced a number of innovative technologies, including a chimney solar dryer that more efficiently dries and preserves fruits and vegetables for long-term storage, and a simple tool called the DryCard that lets farmers know if food is safe for dry storage.
Additionally, researchers facilitated the adoption of improved agricultural methods, such as drip irrigation in Guatemala, and conservation agriculture for vegetable production and a packinghouse in Cambodia, that led to climate and social resilience.
The Horticulture Innovation Lab is a part of Feed the Future, the U.S. government’s initiative to combat global hunger and poverty. It brings partners together to help some of the world’s poorest countries harness the power of agriculture and entrepreneurship to jump-start their economies and create new opportunities. — By Matt Marcure, UC Davis
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Researchers & Grower-Shipper Association Collaborate to Battle INSV
Grower-Shipper Association of Central California (GSA) — Implementing effective disease and pest management strategies is a continual challenge for farmers. While these challenges are not new in agriculture, they impact more than just farmers. Lower yields due to disease and pest pressure affects farm employees and harvesting crews too and can also inhibit our ability to provide a steady supply of affordable and healthy produce to consumers.
Unfortunately, farmers of leafy greens are now dealing with the re-emergence of a damaging disease called thrips-vectored Impatiens Necrotic Spot Virus or INSV. According to local farm advisors this increase in INSV is often accompanied by Pythium wilt infections, which is a relatively new problem in the region.
Lettuce fields are infected by INSV via thrips migrating in from infected host plants in the early spring. Fields infected by INSV cause stunting, yellowing, wilting of the outer leaves and eventual death for leafy greens. Currently, there are no effective treatments for INSV and Pythium wilt on organic and conventional lettuce farms.
To support farmers as they battle INSV, GSA created a new task force to identify major research questions, examine treatment strategies, develop treatment efficacy trials and build a grower education program specific to these diseases.
Mary Zischke, former Executive Director of the California Leafy Greens Research Board, was hired by GSA to lead and coordinate Task Force activities. In addition, to assist local farm advisors and help advance University of California cooperative research efforts, GSA added Jasmine Rodriguez to its team. Rodriguez is currently working toward her biology degree at California State University, Monterey Bay and also serves as a laboratory assistant for entomology research projects at the UC Cooperative Extension in Monterey County.
“Mary and Jasmine will provide our industry with the additional personnel resources and experience as we combat this complex disease and pest control problem,” says Christopher Valadez, GSA president.
To further expand resources and personnel, GSA has applied for a California Department of Food and Agriculture Specialty Block Grant. The grant would allow scientists to conduct multi-year field research trials assessing the effects of common crop rotation sequences, monitor Pythium wilt and INSV occurrence in commercial fields, conduct greenhouse studies to characterize the interactions between Pythium wilt and INSV in lettuce to understand their impacts on overall plant health and disease management.
If awarded the grant, the GSA team will work with researchers from California State University, Monterey Bay and U.S. Department of Ag, Agricultural Research Service in Salinas. Grant outcomes would include knowledge of the impact of crop rotation on Pythium wilt and thrips populations as well as the interplay between Pythium wilt and INSV and how to jointly manage them.
While GSA is hopeful the grant provides future resources, we will continue moving needed work forward to uncover potential answers and treatment strategies so farmers in our region can minimize losses. Farming equates to surmounting challenges and GSA is committed to supporting farmers as they face those challenges.
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Field Bindweed Yield Impacts on Processing Tomatoes May be Less than Expected
Figure 1. Field bindweed (Convolvulsus arvensis) Field bindweed (Convolvulsus arvensis) is considered by many tomato growers to be the most problematic of all weeds in California production areas. Indeed, field bindweed and the closely related morning glory weeds were ranked the 8th most troublesome weeds in North America in a recent survey by the Weed Science Society of America. The rapid adoption of drip irrigation and the economic necessity of maintaining the beds and replanting with only minimal tillage for multiple seasons in processing tomatoes has created a system where field bindweed has become more prevalent. Field bindweed is extremely difficult to control because it propagates from seed and vegetatively from buds formed in the roots. Seedlings can be controlled with tillage when very young, but they become perennial very rapidly. Chemical control of seedlings is possible, but established plants are much more difficult to control. Established plants often have a large root system relative to the amount of top growth, and thus are extremely tolerant of post emergence herbicides such as carfentrazone (Shark), glufosinate (Rely), and glyphosate (Roundup).
Bindweed is a headache not only for its persistent and pernicious growth habit and ability to reduce tomato yields, but also because it can physically stop a processing tomato harvester in the field. Vigorously growing vines can become entangled around the shaker and conveyor belts, requiring the equipment operator to shut down and manually clear out the foliage.
Several years ago, myself and other UC researchers conducted herbicide trials evaluating field bindweed control — with marginal success. In a given year and location, most of the registered herbicides in tomatoes gave only temporary suppression – about 40 – 80% bindweed control at 8 weeks after transplanting. Best results were observed where herbicides were stacked: trifluralin (Treflan) pre-plant incorporated followed by rimsulfuron (Matrix) post. Glyphosate helped in situations where the bindweed emerged early and could be applied before transplanting (Figure 2).
Figure 2. Bindweed control plots at UC Davis. Untreated control on the left, glyphosate, trifluralin, and rimsulfuron on the right. Earlier this year, I was asked to summarize the effects of weeds on processing tomato yield. This made me go back and look at this work, but with a slightly different emphasis: impact of weed control (or really, lack of weed control) on yield. To increase the size of my dataset, I also included data from trials done at UC Davis. Where I had data for both yield and weed control in good, replicated trials, I performed a regression analysis comparing % weed control and % relative yield (relative yields remove the year-to-year and location variability). In the end, I used 4 trials from 2012-13 (Table 1).
Scott Stoddard, UC Cooperative Extension Merced-Madera Counties Vegetable Crops and Soils Farm Advisor Surprisingly, these data suggested that where bindweed dominated, it did not have a big impact on processing tomato yield. Even with just 50% control 8 weeks after transplanting, potential yield was 88-95%. This may have occurred because bindweed does not shade out the tomato canopy nearly as much as some of the common annual weeds. However, when tall broadleaf weeds dominated, such as pigweed, nightshades, and lambsquarters, yields dropped rapidly. I had some plots with a 99% yield drop if these weeds were allowed to grow all season. In this situation, the weeds towered over the tomato canopy.
There have been no new registered herbicides in processing tomatoes in the last 10 years, while robotic weed control has progressed rapidly during this time. Unfortunately, neither our current slate of registered herbicides nor robots provide adequate control of field bindweed. This may not matter as much as previously thought, however. The annual grasses and broadleaf weeds have far greater yield impact, especially when they grow tall and shade out the crop. Thankfully, there are several registered herbicides that provide effective control of those weed types. — By Scott Stoddard, UC Cooperative Extension
Soil-Biodegradable Mulch In Strawberry Field Day, Aug 17
The UC Cooperative Extension, Washington State University and Monterey Bay Marine Sanctuary have been working together this past year field testing five different formulations of biodegradable bed mulch in strawberry. See five types of soil-biodegradable mulches (BDMs) applied to strawberries in Salinas Valley. Learn what a BDM is, what it is made from, and comparative economics with traditional PE plastic mulch. See first-hand how it is performing in the field and learn from other farmers who are trialing it about their experiences and expectations. Learn about how plastic impacts soil health. For more information on the event, contact Jazmine Mejia-Muñoz at jazmine@californiamsf.org or call (661) 331-2612. Register HERE All local and state health guidelines will be enforced. If you have not received a Covid vaccine please wear a mask.
Location:
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