Almond Growers to Play Critical Role in Solving Bee Loss Puzzle

Taylor Hillman Tree, nut & vine crops

beeThough in most cases beehives have already left the orchard, almond growers can still play a vital role in understanding honey bee health impacts.

Over recent weeks there have been a number of reports from beekeepers about damaged hives, specifically, the loss of immature bee brood at the close of and following this year’s almond bloom. While science-based consensus on the cause is still undetermined, both beekeepers and the almond community are working to address the knowledge gap.

Beekeepers’ Survey

To begin to assess the scope of this year’s impacts, the California State Beekeepers Association and others have recently sent out a beekeeper survey. This survey highlights the importance of proper incident reporting and investigation. Early estimations indicate that losses are significantly less than those reported in 2014; however, the continued occurrence is troubling.

The Almond Board of California (ABC) is actively coordinating with beekeepers and responsible agencies to ensure proper investigations are carried out on affected hives. Prior to the 2016 pollination season, a coordinated approach was agreed upon by the California Department of Pesticide Regulation (DPR) and Bee Informed Partnership (a research and outreach program providing technical support to beekeepers that is funded primarily by USDA with support from others) to address sampling needs for affected hives both in the state and those that have moved out of state since bloom. The Almond Board will be among those providing financial support for analysis of these samples.

What Growers Can Do

The role that growers can play in this issue is fourfold:


  1. During bloom, fungicide applications should be avoided when bees are foraging in the orchard and applications timed for the late afternoon and evening when bees and pollen are not present. Additionally, application of insecticides or tank mixing insecticides with fungicides should be avoided during bloom, and instead, growers should opt for alternative integrated pest management (IPM) insecticide timings until more is known about the impact of insecticides on honey bees, particularly on young developing bees in the hive.


  1. Unfortunately, at this time there are still some hives present in orchards. Growers who still have hives in their orchard should monitor their health by checking for excessive numbers of dead bees in front of hives or clogged hive openings, specifically with dead brood or undeveloped pupae. A full list of signs and symptoms for dead or health-impacted honey bees can be found on page 17 of ABC’s “Honey Bee Best Management Practices for California Almonds” (Honey Bee BMPs). Additionally, growers who still have hives in their orchards should contact their beekeeper about appropriate hive removal timing. With orchards far beyond petal fall, bees are no longer providing pollination services and will fly farther afield to find pollen, risking exposure in adjacent crops as well as inside the orchard as normal post-pollination activities occur. The Honey Bee BMPs specify that bees can be removed when 90% of the flowers on the latest blooming varieties are at petal fall as beyond this, no pollination is taking place.


  1. If suspected pesticide-related hive impacts are observed in the orchards, or if growers hear about them from their beekeeper, a report should always be made to the local county agricultural commissioner regardless of where the hives are now located. Without proper reporting, there is no official record of the incident or investigation to collect the information necessary to advance knowledge of bee health risks. It is especially important to gather information about pesticide application timings and conditions, product names and active ingredients. Pages 17 and 18 of the ABC Honey Bee BMPs further explain what information is helpful to report and what to expect in an investigation.


  1. To facilitate proper investigation of affected hives that have been removed from the orchard, growers and beekeepers can contact the Almond Board’s director of Agricultural Affairs, Bob Curtis, at or (209) 343-3216.


While the Almond Board’s Honey Bee BMPs make important recommendations for protecting honey bee health, it is important to recognize that they are both voluntary and go beyond current pesticide labels. As outlined in the Honey Bee BMPs, most bee label warnings are based solely on adult acute toxicity studies. The U.S. Environmental Protection Agency is now requiring data on the possible effects of these materials on young, developing bees in the hive. It will take time to obtain and analyze that data to determine if pesticide label revisions are necessary and pass those on to the market.

Even as growers adopt and follow the Honey Bee BMPs, the fact that incidents affecting honey bee health continue to occur highlights the need for thorough, science-based investigations of pest control materials and their impacts on honey bees of all life stages. Both growers and beekeepers can help advance this conversation by properly reporting any suspected incidents they observe for documentation and further investigation.

More detailed guidelines on hive removal and honey bee health considerations are available through the BMP guide and related Honey Bee BMP materials online at