Virtual Avocado Field Day 2021
Zooming to Healthier Trees and Soils
April 14, 2021 (1 - 3pm)
Presented in partnership with the California Avocado Society, Inc.,
California Avocado Commission, and UC Cooperative Extension
as part of the California Avocado Growers Seminar Series
and the CDFA Healthy Soils Program
Pruning strategies for optimum yield and quality
Gabriel Filipe, Sr Director of CA Sourcing and Farming, Mission Produce
Trialing new rootstock varieties
Lauren Garner, Professor of Horticulture, Cal Poly San Luis Obispo
Scouting for pests and updates on biological pest control
David Headrick, Professor of Entomology, Cal Poly San Luis Obispo
Building berms for hillside orchards
Johnny Rosecrans, Sr Farm Technician, Cal Poly San Luis Obispo
Cover crops and soil health
Charlotte Decock, Asst Professor of Soil Science, Cal Poly San Luis Obispo
Ben Faber, Soils/Water/Subtropical Crops Advisor, UC Cooperative Extension
Claire Balint, Interim Director, Cal Poly Center for Sustainability
Special thanks to the Brock Center for Agricultural Communication
Video recordings will be available on this website after the virtual live event
For questions, please email firstname.lastname@example.org
- Author: Pam Kan-Rice
Growers considering producing avocados in San Diego County with high-density plantings now have help to determine the economic feasibility. A new study on the costs and returns of establishing and producing avocados in San Diego County has been released by UC Agriculture and Natural Resources' Cooperative Extension, UC Agricultural Issues Center and the UC Davis Department of Agricultural and Resource Economics.
Avocado has been one of the prominent crops produced in Southern California since the early 1950s. California avocado production peaked in 1987-88 with about 76,300 acres. San Diego had been the leading producer accounting for about 60% of the acreage.
“Beginning in the early 1980s, there has been a continuous decline of acreage and production of avocados in San Diego County, said Etaferahu Takele, UC Cooperative Extension farm management advisor for Southern California and co-author of the study. “This is mainly because of the expansion of urban development that has increased the cost of producing the crop and especially the cost of water, reaching to up to $2,000 per acre feet in 2020.”
High-density planting increases profitability of avocado production given there is suitable land for high-density orchard development.
Although the cost of water accounts for 44% of the total production cost in the high-density planting, the water cost is proportionally less than in the conventional planting of 145 trees per acre when distributed over a higher yield per acre, the authors write.
Their cost analysis describes production operations for avocados planted at 430 trees per acre, with an expected life span of 40 years. The study includes a detailed summary of costs and returns and a profitability analysis of gross margin, economic profit and a break-even ranging analysis table, which shows profits over a range of prices and yields. Growers can identify their gross margin and returns to management based on their yield and prices received.
Input and reviews were provided by a UC Cooperative Extension farm advisor and grower cooperators in San Diego County. The authors describe the assumptions used to identify current costs for avocado establishment and production, material inputs, cash and non-cash overhead.
The new study, “Avocado Establishment and Production Costs and Profitability Analysis in High Density Planting, San Diego County-2020,” can be downloaded for free from the UC Davis Department of Agricultural and Resource Economics website at http://coststudies.ucdavis.edu and UCCE Riverside County Farm Management website at https://ucanr.edu/sites/Farm_Management/Costs_and_Returns. Sample cost of production studies for many other commodities are also available on the websites.
For additional information or an explanation of the calculations used in the studies, refer to the “Assumptions” section of the report or contact Takele at (951) 683-6491 Ext. 243 or email@example.com or Donald Stewart at the UC Agricultural Issues Center at firstname.lastname@example.org.
Guacamole from Mexico Fuels Surge of Avocado Imports
This new article from the Giannini Foundation looks at factors associated with recent rapid growth in demand for processed avocados, including adaptation and adoption of High-Pressure Processing (HPP) technology. California producer- and importer-funded research and promotion programs have changed avocados' image to that of a healthy super-food. Expanded imports from Mexico have improved year-round availability of fresh and processed products, and guacamole's popularity.
Hoy F. Carman examines how the growth in demand for processed avocados, together with avocados' new image as a healthy superfood, has fueled imports from Mexico in new #AREUpdate article. Read More: https://t.co/qVdwlizU2V #avocado.
- Author: Brad Buck, U of F
UF/IFAS researchers are working on a decision-support app to help policy makers and growers decide the best regional treatment options for laurel wilt disease, which is challenging Florida's $35 million-a-year avocado crop.
Laurel wilt disease is spread by several ambrosia beetle vectors. People, whether they grow avocados or not, can spread the beetles when they move infested wood products – for example, firewood and wood-turner wood -- UF/IFAS researchers say. UF/IFAS researchers are trying to get all this spreading under control.
To help develop the app, scientists are using the HiPerGator, a supercomputer on the main University of Florida campus in Gainesville, to analyze massive amounts of data.
“This network analysis app will aid policy makers by providing input about how such things as subsidies or penalties for disease management are likely to affect growers' management decisions and resulting disease spread,” said Berea Etherton, a doctoral student in plant pathology in the UF/IFAS College of Agricultural and Life Sciences. “Better regional management as a whole benefits individual growers.”
Scientists hope to gain better regional control of laurel wilt through machine learning for analysis of satellite-images. Those analyses train an artificial intelligence system to recognize patterns from remotely sensed images, said Etherton, who's conducting the research under the supervision of her advisor, UF/IFAS Professor Karen Garrett.
“In the next steps for the project, we plan to integrate satellite image analysis and disease recognition to support decision makers considering the best management strategies,” Garrett said. “The computational demands of the machine-learning tools in this project will benefit from the new HiPerGator resources.”
The UF supercomputer will allow for rapid analysis of large data sets, Etherton said. This project is designed to pass the benefits of the HiPerGator on to the growers, as decision support will include input from satellite images and high-speed processing.
Florida avocados are grown almost entirely in Miami-Dade County. Many consumers love to eat them in a variety of ways, including in guacamole dip. But even as laurel wilt disease damages avocado trees, demand for the fruit continues to rise in global markets. According to UF/IFAS economists, about 80% of Florida's avocados are sold outside Florida and the industry has an economic impact of about $100 million to the state's economy.
Garrett and Etherton are working with researchers at the UF/IFAS Tropical Research and Education Center and the U.S. Department of Agriculture. They all hope the app will help control laurel wilt on a regional basis.
“Any technology that is accessible, efficacious and economical and helps producers combat laurel wilt is welcome,” said Jonathan Crane, UF/IFAS professor of horticulture and a tropical fruit Extension specialist at TREC.
“Managing crop diseases is challenging, because the success of one grower's management strategies often depends on how well other growers are managing the disease. We are working to contribute to regional management strategies,” Garrett said.
In many ways our pest and disease management of fruit tree crops are exacerbated by our cultural practices. Avocado and citrus offer some very clear demonstrations of how we manage our trees can lead to reduced pesticide use. From the beginning, our selection of rootstock and scion can help lessen pest and disease problems. In both avocado and citrus we have good rootstocks which can handle problems, such as root rot more effectively than seedling rootstocks. So it is imperative that if you know that drainage will be a problem, starting off with the right, healthy rootstock helps. Also scion selection can have a major impact, as well. For example, ‘Lamb' avocado is much less prone to persea mite than is ‘Hass'. This pest can significantly impact a spray program and planting ‘Lamb' could mean virtually no sprays for this pest. Selling the ‘Lamb' fruit is then the challenge There are similar examples in citrus where one variety is more prone to a pest or disease than another.
Irrigation is probably the most important cultural factor in managing tree disease. Over, under and improperly timed irrigations are the conditions necessary for many root diseases. The Phytophthora spp. fungi are looking for distressed root systems brought on by waterlogging and other stressful situations. Other conditions, such as wetted trunks can also bring on some trunk diseases, like gummosis in citrus and crown rot in avocado. Simply preventing irrigation water on the trunks can limit these diseases. Other diseases, such as black streak, stem blight and bacterial canker in avocado are bought on by soil moisture stress.
Nutrients, especially nitrogen management, has been long known to affect levels of insects, such as scale, mealy bug and aphid. Encouraging lush growth helps sustain these insects, so reducing this growth tends to lower their numbers. Managing when canopy growth occurs can affect pest severity. Avocado thrips build their populations in the spring and moves easily from leaf to fruit causing significant scarring. By promoting leaf growth at flowering time with a nitrogen application, keeps the insect on the leaves and reduces fruit scarring. This also promotes growth that replaces leaves that have been damaged by persea mite. Likewise the incidence of citrus leaf miner damage can be reduced if spring pruning is avoided so that a flush of growth does not occur at the same time as the population is building. Timing of pruning is important in lemons to avoid wet periods of rain and fog to reduce the spread of hyphoderma wood rot fungus when its fruiting bodies are active.
Pruning can change pest pressure by changing the humidity in the canopy, introducing light and changing the climate supporting disease and pests. By making spray coverage more thorough, it also makes for a more effective application. Modified skirt pruning can have significant effects on mealy bug and scale control, fuller rose weevil incidence, ant colonization and snail damage. It's important that the trunk be protected as an avenue of movement for snail and ant control to get the best effects of this pruning. Skirt pruning also reduces problems with such weeds as bladder pod and the ladder effect of brown rot in citrus – fungal propagules splashed from the ground onto low-hanging fruit, which in turn is splashed to higher fruit.
Keeping a canopy clean of dust and fire ash also makes for more efficient biological control. Because predators are slowed in their search, they are less efficient. They also spend more time grooming their sensory organs, and this also slows them down. Parasites such as wasps are actually slowed by the physical abrasion to their tarsi. Dust also creates a drier environment, which is more hospitable to our pest mites. Watering picking rows, roads and even the trees themselves can lessen mite populations. Use of cover crops can also reduce dust and potentially provide pollen and nectar for predators and parasites. Of course cover crops create a whole new set of management issues, such as colder winter orchards and snails.
Finally harvest timing to avoid pest and disease is often overlooked. In avocado, fruit is often set in clusters. Greenhouse thrips love the microclimate created, and if in a size-pick the cluster is reduced, greenhouse thrips will often not be a problem. Harvest timing is also important in citrus. Fruit left too long on the tree can often develop septoria fungal spot. Picking in a timely manner reduces the incidence of this disease.
These are just a few examples of how cultural practices at the right time can reduce pest and disease problems.