With most of the fruit off the trees for the 2025 season, it’s time for California avocado growers to set their sights on nurturing the set for next year. Fertilization, preparing the soil, managing irrigation, and addressing pest threats are some of the critical actions to promote the health of your avocado trees and plan for the season ahead.
To help safeguard groves and optimize productivity in the upcoming season, West Pak’s avo experts in the field have collaborated to provide these essential insights and guidelines for fall 2025.
- Check for deficiencies & nutrient needs: While spring is ideal for soil testing, fall is the time for leaf analysis.
- Soil prep: Prepare the soil to tackle nutrient depletion and moisture regulation, considering potassium applications if you harvested a large crop this past season.
- Root support: Many growers are having success with humic acid applications during the fall root flush in combination with Phosphite.
- Monitor tree health: Regularly check for root diseases and implement good irrigation practices to limit dry and wet cycles. Growers with high levels of Phytophthora should consult with their Pest Control Advisor (PCA) about applying Orondis. This fungicide has recently been registered for use in California and works directly against the Phytophthora propagules in the soil, rather than against the pathogen in the tree.
Irrigation
- Water deeply and infrequently: Avocado trees prefer infrequent, deep watering, so water thoroughly only when the soil begins to dry out. Micro-sprinklers are especially beneficial this time of year, as they allow for precise water application, delivering water to the roots without wetting the trunk.
- Adjust for the season: As the rainy season approaches, you may need to significantly reduce your automatic irrigation and only water if there is a prolonged dry spell.
- Monitor your trees: Pay attention to the tree’s water usage to avoid overwatering, which can lead to root issues.
Fire Hazard Management
- Weed Management: Clear vegetation, dry grass, and debris from trees and structures to create a defensible space around your grove.
- Pruning: Regularly prune low limbs and remove dead wood to reduce fire fuel.
- Wood Chips: Spread wood chips thinly for mulching; avoid large piles that can smolder.
- Sprinkler Systems: Use metal pipes and risers to minimize fire risk. Preemptively apply water during fire threats to create a moisture buffer.
Wind Abatement
- Windbreaks: Planting windbreaks around groves reduces wind intensity and protects trees from losing fruit or sustaining structural damage. As eucalyptus trees are phased out due to fire hazards, there are many new varieties available.
- Protecting Young Trees: Stake young trees in windy areas to prevent root damage from rocking.
- Tree Shape Maintenance: Regularly prune trees to maintain a shape that minimizes wind resistance, preventing them from acting like sails during high winds.
Navigating Freeze and Frost
- Frost vs. Freeze: A frost occurs when the ground radiates heat, and cold air settles near the surface. A freeze happens when cold air masses move in, lowering temperatures. Manage frost conditions with wind machines or micro-sprinklers and freezes by adding heat using orchard heaters.
- Staying Alert: Growers need to be mindful of frost forecasts and adjust their irrigation accordingly to have a moderately moist soil prior to the frost event.
- Protecting Young Trees: Younger trees are more vulnerable to frost than mature trees. Shield them from frost using insulation wraps or burlap covers.
Pest Control
Pest control is vital for avocado growers facing challenges like Persea mite and thrip damage, fruit fly quarantines, gopher control, and pests like rats and squirrels, all of which can affect tree health and harvest.
- Be Informed: Stay updated on pesticide permits and treatments, especially for thrip damage and controlling other pests.
- Permit Status: Check your pesticide and restricted materials permit status to avoid delays in renewal as the 2025 season wraps up.
- Seek Guidance: Consult your certified Pest Control Advisor (PCA) regularly and follow their recommendations accordingly.
Cultural Controls
- Grove Hygiene: Keep the area around tree trunks clean of leaves and debris to discourage field mice that prefer cover for protection.
Physical Controls
- Tree Protection: Wrap sheet metal around the base of the trunk to prevent squirrels and other climbers from accessing the fruit.
- Trapping: Place rat-sized snap traps or box traps on the ground or on limbs, using baits like peanuts, almonds, walnuts, or melon rind.
- Bait Stations: For larger populations, use tamper-resistant bait stations with appropriate baits, but ensure they are labeled for orchard use.
Thorough preparation and proactive management are crucial as we transition into the 2026 season. By focusing on soil health, water management, fire hazard mitigation, pest control, and tree protection, you can set the foundation for a fruitful year ahead. Staying informed, seeking expert guidance, and implementing these essential practices will both enhance the health of your avocado trees and boost overall productivity. If you have any questions or concerns, please contact your local field rep.
