What do we know about the impact of colony losses to almond yields?

Almond growers have reported anecdotally that some received weaker hives than they had contracted for. There is no comprehensive data to evaluate hives delivered to growers. 

The USDA National Agricultural Statistics Service (NASS) annual subjective estimate was released on May 12, 2025, projecting a 2.8 billion pound crop, which would be 3% above last year’s crop. According to the USDA, the number of bearing acres is up by 10,000 over last year. However, the previous 10-year weighted average yield is 2,096 pounds per acre. Using the Subjective Estimate of 2.8 billion pounds and the forecast 1.39 million acres produces a forecast yield of 2,014 pounds per acre, clearly a below average crop. 

Yields have been down the last several years as growers worked to reduce costs and curtailed crop inputs due to poor profitability. There is also evidence in some regions that the record-breaking heat last summer may impact yields this year. 

A second objective estimate will be released by NASS in July, before harvest begins. 

Despite the lack of evidence to date that the high hive losses have impacted this year’s crop, the almond industry remains highly concerned about the future impacts on beekeepers and pollination services. In collaboration with honey bee organizations, the almond industry plans to invest in a new pilot with commercial beekeepers to demonstrate the efficacy of varroa treatment approaches. 

Now that we know the viruses that were found, what should beekeepers do or not do? 

Deformed wing virus A and B and acute bee paralysis are spread by Varroa mites and signs of Amitraz resistance genes in the mites were found in virtually all collected mite samples. Guidance on treating honey bee colonies for Varroa and avoiding the development of Amitraz resistance can be found at Hive Management – Honey Bee Health Coalition.

As in all virus containment, beekeepers should: 

• Never let varroa levels get high (above a 2% infestation threshold). Monitor for mites to determine when treatments are needed and monitor after treatments to verify mite populations were reduced. 

• Don’t rely on a single miticide to treat varroa.

  • Move away from reliance solely on amitraz 

  • Rotate between different active ingredients with different modes of actions (formic acid, oxalic acid, thymol, hops beta acids) 

  • Combine miticide treatments with other cultural techniques (e.g. brood breaks). 

• Utilize biosecurity measures.

  • Clean hive tools with alcohol or flame in between yards. 

  • Refrain from using equipment from deadout or struggling colonies for a few weeks. This allows time for the viruses to dissipate. 

• If you have colonies that are sick or struggling: 

  • Keep them isolated from healthy colonies. 

  • Minimize moving frames from sick colonies to healthy colonies. 

• Healthy hives are more resilient.

  • Replace old black comb with foundation regularly. Old black comb can harbor bacteria, fungal spores and pesticides which can further contribute to colony stress.

  • Make sure your colonies have healthy, well-mated, young queens. 

  • Ensure that your colonies have adequate food stores. If they do not, provide supplemental feeding (see the HBHC’s Nutrition Guide.)