It’s been an unusual harvest season for California almonds.
In July, the USDA National Agricultural Statistics Service predicted that this year’s crop could be the second largest in history, with an estimated harvest of 3 billion meat pounds. In early August, a rat infestation surged across 100,000 acres of orchards in Fresno, Merced, Kings and Kern counties, causing widespread damage to roots, nuts, and irrigation systems. Several weeks later, news began to spread about a new disease that has spread across all of the state’s almond-growing regions: red leaf blotch.
Let’s get proactive! If you’re battling a rat infestation, the Los Angeles Times recommends using a combination of tracking tunnels, cameras, and ink cards to identify rat behavior in your orchard. Use that information to launch a targeted baiting program, and keep your bait stations full of oats treated with diphacinone for four weeks. For a long-term solution, place snap traps into trapping tunnels after your baiting program is complete.
If you’re concerned about red leaf blotch — which appeared on the border of Merced and Madera counties in May 2024, having previously impacted the almond crop in the Mediterranean and Middle East — then it’s important to use a preventive fungicide before symptoms appear. Fungicides from FRAC groups 7 and 11 are the most effective, particularly when their active ingredients are mixed together. Researchers recommend applying those fungicides at three different times: first at petal fall, then again at two and five weeks later, particularly if it’s been a rainy season. To prevent further spread, remove infected leaf litter from your orchard floor, accelerate decomposition by applying urea (1-2 pounds per 400 pounds of leaves) to your fallen leaves to accelerate decomposition, and apply Zinc sulfate (20-40 pounds per acre) in late-October to early-November to speed up leaf fall and prevent inoculum build-up.
Finally, remember that you have partner in Fruit Growers Supply! Give us a call today, or visit a supply store near you to speak with a specialist about ways to protect your almond crop.