- Author: Ben Faber
Evaluating claims of new products that could potentially improve yield and tree health is a daunting task. Every week I get calls and literature from people promoting fertilizers and techniques that "resist insects," "reduce salt levels in the soil," "increase crop quality," "release that natural fertility of your soil," and numerous other claims. There just is not enough time in the day to approach each and every one of these materials or techniques, even though some may, in fact, be promising.
So what does a grower do? You hear about a new product. It only costs $20 an acre to apply. Might as well fly it on all 50 acres. But then, how do you know it has done anything? What results do you have to compare it with? Last year's yield which was miserable? We know how variable avocado yields are, so last year's harvest may not be a good comparison.
When we conduct field trials, we assume a clear comparison is available to test the effects of the treatment. With field trials, there are usually small plots, repeated several times (at least three), and arranged in an apparent haphazard (random) fashion. The reason is threefold: 1) to account for variability in the field, 2) to prevent a systematic bias in favor of one treatment over another and 3) to see if differences in treatments are due to chance or to the superiority of the treatment.
How are observational trials different from replicated one? The big difference is that they are not replicated. Each treatment occurs only once, so we have no measure of the natural variability in the field or trees. As a result, we risk thinking we have a difference due to treatment which is actually due to field variability. Without replication there is no way to tell.
Let's examine this replication idea a little more closely. We had a frost trial where we applied copper or a water control spray to young trees in November. Copper is a noted bactericide and the idea was to control the frost-nucleating bacteria. Forty trees, randomly spaced in the orchard were sprayed with either a dilute copper spray according to instructions or water alone. We evaluated frost damage to the trees in January. The first counts showed 40% frost damage with the copper spray and 60% with the water alone. Great. Let's go out and spray the whole orchard next year with copper. However, successive counts showed 50% frost damage with the copper and only 30% from the water. In the end, there was no significant difference to trees that had been sprayed with either material.
These results show the natural variability in biological systems and demonstrate the disadvantages in looking at results from a non-replicated trial based on a single year. This becomes even more important when interpreting information from a trial site different from your own. If every grower sprayed a non-replicated treatment at their own ranch, the risk of coming to the wrong conclusion about that treatment at each location is still 50%. Just like flipping a coin. Is that worth spending money on?
As each of the variables (soil type, irrigation quality, management, etc.) increases, the risk of making a poor decision about a product or practice increases, as well. You can see that there are difficulties associated with relating information from a non-replicated trial based on a single year of data at a different location to your own situation.
How does someone go about evaluating a new practice or material at home without going through all the complications of a complicated research trial? Mary Bianchi, retired Farm Advisor in San Luis Obispo and I came up with a little checklist.
- Be conservative in your approach and critical observations. Resist the urge to spray the whole grove. Leave something, so that a comparison can be made. Preferably run a side-by-side comparison.
- Use consistent farming practices across all areas of the trial.
- Compare the new practice to one which is a standard for your operation.
- Don't bias your results by implementing the new practice where it stands to have the best effect anyway. For example, don't spray boron on the trees that always give a good yield.
- Run the test more than one year and in more than one location, especially if the new practice is costly.
- Talk to the industry and use the experience of others in different locations as a check on your own experience. A good place to swap ideas is at the California Avocado Society/CA Avocado Commission/University of California Cooperative Extension sponsored bimonthly meetings.
Research does not need to be complicated, but it needs to be thought out before hand with consistent data collection and given time. And time is critical, especially for nutrient studies and with a tree like avocado, that has a prolonged bloom with alternate bearing and usually more than one crop at a time. The effects of application timing at a given rate might not be determined for several years of crop yield. Persistence is the key to experimentation. Unless it's a pesticide trial, do you see results in the first year.
- Author: Ben Faber
Evaluating claims of new products that could potentially improve yield and tree health is a daunting task. Every week I get calls and literature from people promoting fertilizers and techniques that "resist insects," "reduce salt levels in the soil," "increase crop quality," "release that natural fertility of your soil," and numerous other claims. There just is not enough time in the day to approach each and every one of these materials or techniques, even though some may, in fact, be promising.
So what does a grower do? You hear about a new product. It only costs $20 an acre to apply. Might as well fly it on all 50 acres. But then, how do you know it has done anything? What results do you have to compare it with? Last year's yield which was miserable? We know how variable avocado yields are, so last year's harvest may not be a good comparison.
When we conduct field trials, we assume a clear comparison is available to test the effects of the treatment. With field trials, there are usually small plots, repeated several times (at least three), and arranged in an apparent haphazard (random) fashion. The reason is threefold: 1) to account for variability in the field, 2) to prevent a systematic bias in favor of one treatment over another and 3) to see if differences in treatments are due to chance or to the superiority of the treatment.
How are observational trials different from replicated one? The big difference is that they are not replicated. Each treatment occurs only once, so we have no measure of the natural variability in the field or trees. As a result, we risk thinking we have a difference due to treatment which is actually due to field variability. Without replication there is no way to tell.
Let's examine this replication idea a little more closely. We had a frost trial where we applied copper or a water control spray to young trees in November. Copper is a noted bactericide and the idea was to control the frost-nucleating bacteria. Forty trees, randomly spaced in the orchard were sprayed with either a dilute copper spray according to instructions or water alone. We evaluated frost damage to the trees in January. The first counts showed 40% frost damage with the copper spray and 60% with the water alone. Great. Let's go out and spray the whole orchard next year with copper. However, successive counts showed 50% frost damage with the copper and only 30% from the water. In the end, there was no significant difference to trees that had been sprayed with either material.
These results show the natural variability in biological systems and demonstrate the disadvantages in looking at results from a non-replicated trial based on a single year. This becomes even more important when interpreting information from a trial site different from your own. If every grower sprayed a non-replicated treatment at their own ranch, the risk of coming to the wrong conclusion about that treatment at each location is still 50%. Just like flipping a coin. Is that worth spending money on?
As each of the variables (soil type, irrigation quality, management, etc.) increases, the risk of making a poor decision about a product or practice increases, as well. You can see that there are difficulties associated with relating information from a non-replicated trial based on a single year of data at a different location to your own situation.
How does someone go about evaluating a new practice or material at home without going through all the complications of a complicated research trial? Mary Bianchi, retired Farm Advisor in San Luis Obispo and I came up with a little checklist.
- Be conservative in your approach and critical observations. Resist the urge to spray the whole grove. Leave something, so that a comparison can be made. Preferably run a side-by-side comparison.
- Use consistent farming practices across all areas of the trial.
- Compare the new practice to one which is a standard for your operation.
- Don't bias your results by implementing the new practice where it stands to have the best effect anyway. For example, don't spray boron on the trees that always give a good yield.
- Run the test more than one year and in more than one location, especially if the new practice is costly.
- Talk to the industry and use the experience of others in different locations as a check on your own experience. A good place to swap ideas is at the California Avocado Society/CA Avocado Commission/University of California Cooperative Extension sponsored bimonthly meetings.
Research does not need to be complicated, but it needs to be thought out before hand with consistent data collection and given time. And time is critical, especially for nutrient studies and with a tree like avocado, that has a prolonged bloom with alternate bearing and usually more than one crop at a time. The effects of application timing at a given rate might not be determined for several years of crop yield. Persistence is the key to experimentation. Unless it's a pesticide trial, do you see results in the first year.
It's not really like this!!
- Author: Ben Faber
Funding of the Citrus Research Board is an investment in pertinent research that supports the industry, making the information accessible to all within the industry from pest control advisors to packing houses to farm managers and others within the industry. The goal is to get the research done and then make sure it is used. CRB represents both large and small growers throughout California.
CRB research programs are funded by grower assessments which attract both federal and state funding, funding which represents a third of the total budget. This funding is used to support such projects as, HLB-resistant citrus rootstocks; the development of effective, low-cost HLB early detection technologies to rapidly remove infected trees; improved biocontrol methods for specific insect control like Asian citrus psyllid, as well as others; pre-and post-harvest citrus research to maintain export markets, amongst many other research programs.
The Citrus Research Board also supports the Citrus Clonal Protection Program (CCPP) with the goal of insuring the safe introduction of citrus varieties, disease diagnosis and pathogen elimination of introduced varieties and the maintenance and distribution of introduced varieties. CCPP serves as the primary source of clean, disease-free budwood and new varieties from Florida. This work is a collaboration between the Citrus Nursery Board, the University of California and State and Federal Regulatory agencies. The CCCP has become a major hub of the National Clean Plant Network for Citrus, resulting in the collaboration with 10 citrus centers in nine states and territories with multimillion dollar funding in support of CCCP's operations.
CRB research supports the California Citrus Quality Council (CCQC) with the primary objective of ensuring that California citrus meets domestic and international phytosanitary, food safety, food additive and pesticide residue regulations. CCQC ensures that California citrus growers have access to export markets for their fresh citrus fruit. Exports represent a third of the California citrus grower profits.
CRB-funded research into the California citrus-breeding program has led to the development of the Tango mandarin, along with others. The core breeding program conducts yield trials throughout the state on all varietal types to give growers information on upcoming new varieties and rootstocks. There is ongoing work to incorporate molecular tools to expedite breeding efforts to find plant materials resistant to HLB.
Along with CRB funding for cutting-edge projects for pest and disease control strategies, the CRB-funded CORE IPM Program led by Beth Grafton-Cardwell has responded to citrus grower needs for modifying existing spray schedule to treat Asian citrus psyllid. The program evaluates rotational sprays at appropriate times to avoid pesticide resistance to ACP.
Finally, this CRB-packaged information has been extended to growers through programs, including: The California Citrus Conference, Post-Harvest Conference and Seminar, and Regional Grower Education Seminars. CRB-funded research is compiled in Citrograph Magazine, the only magazine dedicated solely to the California citrus industry.
- Author: Ben Faber
This is a story about phone calls that come in to my message machine. Yesterday I got 3 calls from PCAs (Pest Control Advisors) and two from growers. The two from growers were from a Papaya grower and the other from a dragon fruit grower that I am working with to develop an industry here in Santa Barbara/Ventura. One is in Carp the other in Montecito. The PCA calls were from two that work on avocado and the other from a citrus grower. I either get a call from an avocado grower direct because they can't afford a PCA or from the manager or the PCA of larger farms. From citrus it is usually the manager or the PCA. These are more developed industries and the grower usually lets the workers take care of problems because they are so familiar with the operations. When it ‘s a new crop, the owner steps in. They want to know all that can go wrong with this new crop.
Blueberries are expanding now along the coast and when we first started working on them 15 years ago, our collaborators were in touch with us constantly. Now it's the managers who call. Its now a developed industry. The same for coffee. When we started working on it we worked closely with out cooperators, now there is a coffee cooperative that takes care of itself. We work with new things. One of the calls from an avocado PCA was about a farm that is being infested with bagrada bug. Everything in the area has dried up from the drought. The bagarada bug normally goes after plants in the brassica family (cabbage, mustard, etc.), many of which are native and growing along streams and on hillsides. The streams and hills have dried up and the bug is now going to the new avocado leaf tissue and the PCA wanted the bug identified and to provide a solution to the problem.
Sometimes the weather works for us and sometimes against us. We've got a parasitic wasp for controlling olive fruit fly. We went out all over southern Santa Barabara county to groves of olive trees to determine where to release the wasp and could find healthy olives, but no olive fruit. No where to make to make releases this year. The weather plays tricks on us. But we keep looking for solutions. Maybe next year we will be able to study if and how the wasp controls olive fruit fly. It does in France.
- Author: Ben Faber
USDA Creates Multi-Agency Emergency Response Framework to Combat Devastating Citrus Disease | |||||
USDA Providing $1 million to Jump Start Citrus Response Framework | |||||
WASHINGTON, December 12, 2013 - The U.S. Department of Agriculture today announced the creation of a new, unified emergency response framework to address Huanglongbing (HLB), a serious disease of citrus that affects several U.S. states and territories. This new framework will allow USDA and its many partners to better coordinate HLB resources, share information and develop operational strategies to maximize effectiveness. "USDA listened to the citrus industry's request for more urgency and greater coordination on the response to HLB and is implementing an emergency response structure," said Secretary Tom Vilsack. "To jump start this initiative and affirm our commitment to industry, USDA is also providing $1 million to be used in support of research projects that can bring practical and short-term solutions to the growers in their efforts to combat this disease. Through the Specialty Crop Research Initiative of the Farm Bill, USDA has provided $9 million in research to blocking the ability of insects to spread HLB to healthy trees. We need Congress to quickly pass a new Farm, Food, and Jobs Bill that continues to support this kind of research to protect a crop worth more than $3 billion in the last harvest." The new framework will bring together USDA's Animal and Plant Health Inspection Service (APHIS), Agricultural Research Service (ARS) and National Institute of Food and Agriculture (NIFA), along with state departments of agriculture and the citrus industry into a Multi-Agency Coordination (MAC) Group for HLB. It will provide industry with a single contact for all the federal and state entities that work on citrus issues and better enable the collective to collaborate on policy decisions, establish priorities, allocate critical resources, and collect, analyze, and disseminate information. The HLB MAC Group will also help coordinate Federal research with industry's efforts to complement and fill research gaps, reduce unnecessary duplication, speed progress and more quickly provide practical tools for citrus growers to use. HLB, also known as citrus greening, is named for the green, misshapen, and bitter-tasting fruit it causes. While this bacterial disease poses no danger to humans or animals, it has devastated millions of acres of citrus crops throughout the United States and abroad. In the United States, the entire States of Florida and Georgia are under quarantine for HLB, and portions of California, Louisiana, South Carolina and Texas are also under quarantine for the disease. The U.S. Territories of Puerto Rico and the U.S. Virgin Islands are under HLB quarantines as well. You can find more information about HLB and the HLB MAC Group on USDA's Multi-Agency Response to Devastating Citrus Disease website. See the USDA Animal and Health Inspection Service's website for additional Q&A Contact: # Note to Reporters: USDA news releases, program announcements and media advisories are available on the Internet and through Really Simple Syndication (RSS) feeds. Go to the APHIS news release page at www.aphis.usda.gov/newsroom and click on the RSS feed link. USDA is an equal opportunity provider and employer. To file a complaint of discrimination, write: USDA, Office of the Assistant Secretary for Civil Rights, Office of Adjudication, 1400 Independence Ave., SW, Washington, DC 20250-9410 or call (866) 632-9992 (Toll-free Customer Service), (800) 877-8339 (Local or Federal relay), (866) 377-8642 (Relay voice users). |
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