Harvest isn’t typically when we talk about honey bee health in California almond orchards but research shows now is when growers can get a jump on improving bee health and their bottom line.
Planting forage in, near, or around an almond orchard can help ensure bee health and pollination at bloom. Orchards have much to gain from nearby forage as well.
Two studies funded by Almond Board of California (ABC) have demonstrated the benefit of supplemental forage to bee health measured by increased queen and colony survival over winter, and overall improved colony health.
In these studies, colony performance was assessed for hives that foraged on rapini mustard versus no forage before almond bloom.
Documented benefits to bee health from forage have led to the emergence of discounted bee rental contracts to almond growers who plant forage. Forage planted in or near an almond orchard could reduce the cost of one of the most expensive inputs for growers each year, and improve the health and pollination abilities of the bees in the process.
Healthy bees pollinate better.
Ongoing ABC research suggests that supplemental forage does not compete with almond blossoms. Honey bees visit almond blooms before the adjacent forage.
Current Almond Board funded research is documenting the value of creating forage bloom “brackets” around almond bloom time which would provide supplemental forage before and after almond bloom, rather than just before as done in earlier studies.
A bracketed approach provides bees with natural nutrition before and after almond bloom when there is a lack of pollen for bees to feed. Poor nutrition is a major cause of colony loss.
Interim food sources
Many hives arrive in orchards before bloom is in full swing and leave after bloom has ended when limited natural forage is available. The study examines the benefits of proving interim food sources to maintain hive health.
Forage can be planted either in close proximity to orchards or within the rows themselves. Either scenario can benefit the bees and the grower.
Forage planted adjacent to orchards, along the margins, or in a nearby field can help with erosion control and curb offsite movement of any pesticide residues. Hedgerows have a long bloom period that can provide forage for bees, plus a refuge for beneficial insects and soil benefits.
Planting cover crops within orchard rows provides several benefits depending on soil and other conditions, in addition to bee health for those growers able to accommodate in-orchard forage.
These benefits include: improved water infiltration, reduced compaction and earlier field access, increased organic matter, and depending on the type of cover nitrogen contribution.
Benefits and tradeoffs
The Almond Board is currently funding and planning research to better quantify the benefits and tradeoffs, including expense in establishment, water use, and management to reduce foreign material at harvest to maintain winter cover crops.
As well, future efforts will incorporate an assessment of cover crops in an orchard setting that are a “best fit” as forage for honey and native bees, and fit into a mowing re-growth and re-bloom cover program desirable for frost control.
Growers should consider planting forage as early as the first part of October before the first rains so it starts growing and outcompeting weeds that germinate.
The best seed mix
There are many resources available online to help determine the seed mix that is right for a specific orchard and provide guidance on planting. One such resource is Project Apis m. online at https://tinyurl.com/yawzu966. Some organizations, including Project Apis m., provide seeds for free.
To learn more about the benefits of forage or best management practices for honey bee health visit almonds.com/Pollination.