Category: Growers

While avocado trees may appear dormant during winter, the winter season is crucial for the accumulation of carbohydrates, or energy , which supports the next growth cycle and fruit crop. Despite the apparent inactivity, both leaves and roots remain functional, and fruit continues to grow, albeit at a slower rate.

Optimizing tree conditions during this period is essential for achieving peak performance in the following spring. To ensure the best outcomes, growers should implement the following cultural practices:

Fertilization

• Review the current fertilizer plan and analyze leaf sample results 
• Develop and adjust the upcoming fertilization strategy as necessary 
• Apply mulch to conserve soil moisture and provide organic matter

Pruning

• Conduct maintenance pruning in frost-free areas to improve light penetration 
• Remove dead wood before the rainy season to prevent disease spread

Irrigation

• Adjust watering schedules to account for lower tree water demand
• Perform irrigation system maintenance to ensure efficiency 
• Implement leaching irrigations to prevent salt buildup in the soil

Frost and Rain Protection

• Inspect and service wind machines for frost protection 
• Enhance natural air circulation within the orchard
• Assess and improve water drainage to prevent waterlogging

By focusing on these key areas, avocado growers can help their trees weather the winter months and set the stage for a productive spring season.

By Gerardo Aldunate, Agronomist, Index Fresh

In October, the Index Fresh team took its show on the road, bringing experts in automated irrigation and Integrated Pest Management (IMP) to California growers. We held our annual seminar in San Luis Obispo, Ventura and Temecula, providing over 150 growers with an opportunity to learn about new tools to improve their growing practices and ultimately increase yield and revenue.

Read on for a taste of the irrigation automation presentations at Seminar 27. To learn more about Pest Control Advisor Tom Roberts’ detailed presentation on Avocado 1PM and for additional information about automated irrigation, watch the video recording at indexfresh.com/seminar/seminar-27/

Automated irrigation, why bother? “In my mind the number one reason to consider automation is to save time and money,” California avocado grower John Cornell told an audience of avocado growers at the Index Fresh Grower Seminar on Oct. 24.

Technology gains in agriculture in recent years have reduced the cost of installing and implementing automated irrigation. A number of companies offer automated systems, and the products range from relatively straightforward to highly sophisticated. What they all have in common is the ability to improve precision and reduce labor – both of which benefit the grower’s bottom-line.

Research conducted by Andre Biscaro, Irrigation and Water Resources Advisor with U.C. Cooperative Extension, demonstrates that most growers over-irrigate early in the season and under-irrigate late in the season. This trend is a product of guesswork related to how much and how often to irrigate. Sensors and automation help to reduce the guesswork and allow for application of the proper amount of water and fertigation at the proper time. As a result, stress is reduced, health improves, and yield increases.

Labor savings can be significant when irrigation is automated. By programming and remotely monitoring irrigation with a smartphone, growers can tailor timing and volume of water applications to parts of their grove with different needs. “An automated system saves a tremendous amount of time compared to having workers running around turning water off and on,” Cornell noted.

Automation doesn’t mean full time farming from your phone, but its two-way communication can prevent costs associated with some of the unpredictable aspects of farming. Cornell relies on a system that shuts down immediately when there’s a break in a line. “You’re not going to wake up surprised at 5 a.m. to find that 10,000 gallons of water have washed away,” he said.

Climatic data from weather stations can be programmed into many of the automated systems available to growers, and Biscaro pointed out that weather stations inform irrigation rates specific to climate and soil conditions across various avocado growing areas. Soil type is also taken into account to ensure that transpiration rate and water holding capacity are both factored into irrigation rates.

By assisting growers in finding the sweet spot for irrigation- not too much and not too little – automated systems conserve water and reduce fertigation costs. When the tree is provided the right amount of fertigation, wasteful fertilizer run-off becomes a non-issue.

Along with improved yield and lower costs, a major benefit of automated systems is enhanced record keeping. Abundant data is available through many of the systems on the market today, and this information, particularly when captured over time, can instruct decisions that further benefit tree health and productivity.

Technological improvements have made irrigation automation more affordable, and Cornell stressed that the benefits quickly outpace the cost. “I’m a bit of a penny pincher,” he said, “so I really do my research.”

The California Avocado Commission (CAC) has announced important changes to the assessment rate for the 2024-25 season. Here’s what you need to know:

Assessment Rate Change

The CAC Board of Directors has approved a new assessment rate of $0.005 (half a cent) per pound on all California-grown avocado varieties. NOTE: THE 2024-25 CAC ASSESSMENT IS A FIXED RATE PER POUND (not a percent of value). The 2023- 24 assessment was 2.25% of the value.

Who Needs To Pay?

All avocado producers in California are required to pay this assessment, with one exception. Growers who have produced an average of less than 10,000 pounds of avocados annually over the past three marketing years are exempt.

If you have any questions concerning the assessment for the 2024-25 crop year or the reporting and payment procedures, please contact CAC Accounting at: accountspayable@avocado.org or call (949) 341-1955.

Avocado growers in California have long grappled with the devastating effects of root rot, a disease caused by the soil borne pathogen hytophthora cinnamomi. This insidious fungus can significantly reduce tree health, fruit quality, and yield, ultimately leading to tree death.

After playing the role of villain in the California avocado industry for decades, P. cinnamomi is finding itself outmatched by a product that hit the market in 2021 called Orondis. A cutting-edge fungicide by Syngenta, Orondis is proving highly effective in controlling root rot.

When our Index Fresh staff presented the 2024 Cultural Seminar Series, they fielded numerous requests from avocado growers seeking more information about Orondis. The following information relies primarily on direct input from Syngenta, as well as experts in the avocado industry.

Why has root rot plagued the avocado industry for so long?

P. cinnamomi thrives in areas of excess soil moisture and poor drainage and can survive adverse conditions as persistent spores in the soil. Avocados didn’t evolve alongside the pathogen, which is thought to have originated in New Guinea, thus never developed resistance to P. cinnamomi. As Farm Advisor-Emeritus Gary Bender pointed out in his recent article in the California Avocado Society’s Avocado Quarterly, “California growers have developed an efficient way to harvest fruit and get it to the packinghouse, but that system also moves the fungus from grove to grove via dirty bins, dirty ladders, truck tires and on the boots of pickers who move from grove to grove.”

How Does Orondis Work?

Orondis, with its active ingredient oxathiapiprolin, operates through a unique mode of action. It targets a specific protein essential for the survival and reproduction of Phytophthora, effectively disrupting its life cycle. By reducing the pathogen’s population in the soil, Orondis promotes healthier root systems, improved water and nutrient uptake, and increased tree vigor.

“Orondis works directly against the Phytophthora propagules in the soil, rather than against the pathogen in the tree, effectively eradicating the pathogen from treated soil for a period following application,” stated Tim Spann in the winter 2021 edition of the California Avocado Commission’s “From the Grove” magazine.

Key Considerations for Orondis Application

Timing: Apply Orondis during periods of root flush, typically in spring and late summer. Note that Orondis has a restricted entry interval of 4 hours and a pre-harvest interval of 30 days.

Method of Application: Soil should be  pre-wetted  before  application. Orondis should be applied through the irrigation water (micro-sprinkler or drip). A general recommendation, using drip irrigation as a guide, would be to allow for at least 6-8 hours (but no more than 10-12 hours of water) to be run after the injection of Orondis.

Rate: Labeled use rates are 4.8 fl oz/A – 9.6 fl oz/A. When establishing a new grove, or for heavy/severe infections, the higher end of labeled rates is recommended on a 6-month retreatment program for the first year. If soil testing confirms a significant reduction in Phytophthora propagules following treatment, you can consider switching to a maintenance program of 4.8 fl oz/A on a 6-month retreatment interval, or 9.6 fl oz/A on a 12-month retreatment interval.

Rotation: Resistance Management guidelines  on  the  Orondis  label instructs growers to limit sequential use of Orondis to two applications before rotating to a fungicide with a different mode of action.

Integrated Pest Management with Orondis

“While Orondis is extremely effective at reducing Phytophthora populations in the soil at low use rates, there is no silver bullet, and incorporating things like cultural controls are also imperative for long-term management of the disease,” states Dr. Jeannette Rapicavoli, Agronomic Service Representative for Syngenta.

Optimal results rely on combining various strategies, including:

Cultural Practices: Help minimize disease pressure by irrigating appropriately (duration and amount), no wetting of trunks, planting on berms, applying organic mulch and ensuring proper tree nutrition Resistant Rootstocks: Using resistant rootstocks can provide a strong defense against the pathogen.

Sanitation: Prevent soil or water movement from infested areas.

Fungicide Applications: Timely applications of Orondis can effectively control Phytophthora.