About Almonds

The overall objective of pollination research is to improve honey bee health.  As it regards crop pollination, that is done by providing honey bee forage.  Almond growers in California and the almond growing regions of California are located where the highest demand for crop pollination services exists.  Forage programs would be geared to 1) educating growers and landowners about the value of providing honey bee forage, 2) accessing the almond grower community via various media outlets and presence at grower meeting and events, and 3) cooperating with local extension leaders, farm advisors, almond industry leaders, beekeepers and bee brokers.  

Completed Almond Research

Please click on titles for more information about research projects
​The Effect of Colony Size and Composition on Almond Pollen Collection
Principal Investigator: Dr. Frank Eischen, USDA, 2007
​Dr. Frank Eischen and colleagues from the Honey Bee Research Unit, USDA-ARS, Weslaco, TX, monitored US and Australian honey bee pollen collection of various colony sizes on a large almond orchard near Shafter, CA. After 20 days of continuous pollen collection, 11 colonies were evaluated for strength, broodnest size and stored pollen.

​Click here to view Dr. Eischen’s 2006 WAS PowerPoint Presentation.
Click here to view Dr. Eischen’s 2007 CSBA PowerPoint Presentation.

The list of treatments in ascending order of pollen collected was:
US 4-frame; US 6-frame; AUS colony established Dec 06 from 4-lb pkg; US 4-frame + 4 lb AUS pkg; US 8-frame; US 4-frame + US 4-frame (2 united 4-frames); US 10-frame; and US 14-frame.

Dr. Eischen’s conclusions are as follows:
-Colonies should have been fed protein supplement prior to bloom.
-Colonies increased pollen collection as their size increased to about 12 frames.
-The addition of an Australian package improved pollen collection by 4-fame colonies.
-The addition of the AUS package greatly improved brood rearing.
-When two US 4-frame colonies were united they collected more pollen than two separate 4-frame colonies.
-Large colonies begin foraging earlier than small colonies.
-Colonies facing east begin foraging earlier than those face west.
-The addition of brood decreased pollen collection.
-Australian colonies collected more pollen than their size would indicate, but the researchers suspect this was due to their behavior in handling pollen traps differently.
The Effect of a Synthetic Brood Pheromone (Superboost, Pherotech) on Almond Pollen Collection by Honey Bees
Principal Investigator:  Dr. Frank Eischen, USDA-ARS, Weslaco, TX, 2008
​Dr. Frank Eischen, USDA-ARS, Weslaco, TX monitored almond pollen collection by colonies treated with Superboost, a synthetic brood pheromone.
Small overwintered colonies (US 4-frame) that were pollen trapped and treated with Superboost collected about 35% more pollen than untreated and trapped colonies. Larger colonies (US 8-frame) showed no increase in pollen collection when treated and trapped. Newly established Australian package colonies, which were pollen trapped, did not respond to treatment with Superboost. In a parallel series of treatments, free-flying colonies matched for origin and size with the trapped groups exhibited no increase in pollen foraging when treated with Superboost.
Crops with scant pollen flows, (eg. blueberries and cucurbits) may be appropriate crops for treating colonies with Superboost as bees are unlikely to harvest enough pollen from the crops alone.
Quantifying the Exposure and Effect of Farmer Applied Pesticides on East Coast Migratory Operations Destined for Almond Pollination
Principal investigator:  Dr. Dennis Van Engelsdorp, Penn State University, 2008
​Along with PAm, the USDA/CSREES, the National Honey Board and the Florida Department of Agriculture contributed to funding this project performed in cooperation with USDA-ARS Beltsville. The purpose of this study was twofold: 1) to analyze pesticide exposure in bees and pesticide residues in pollen of samples taken in the initial national CCD study, and 2) to establish a centralized cost-sharing pesticide screening program at Penn State as a service to beekeepers. One aspect of this project focused on the importance of East Coast migratory operations servicing Western pollinated crops. Of colony samples analyzed during this time period, coumaphos and fluvalinate, two compounds used by beekeepers themselves, were highly prevalent. More pesticide analysis was conducted in other funded research studies
Honey Bee Colony Density and Almond Nut Set
Principal Investigator:  Dr. Frank Eischen, USDA, 2011
Dr. Frank Eischen, Honey Bee Research Unit, USDA-ARS, and a team of researchers, examined the impact of honey bee colony density on almond pollination on ranches near Bakersfield, CA. Both early and late varieties were tested on each of the four ranches. Flower counts and video recordings of bee activity aided in interpreting pollination rates.
Early varieties:  With the exception of Sonora, all early varieties in orchards with higher colony densities had significantly higher pollination rates.   Differences in percent pollination between low and high bee densities ranged from 1.5 to 18.4% for varieties Nonpareil, Fritz, Monterey, Sonora, and Aldrich. Significant increases in pollination occurred in 92% of the paired early variety blocks.
Late varieties:  With the exception of one, all orchards stocked with the higher colony density had significantly higher levels of pollination.  Differences in percent pollination between low and high bee densities ranged from 5.7 to 18.4% for varieties Butte, Padre, and Mission.
Video recordings of bee activity on flowers found that foragers in high bee density blocks remained on a flowering branch longer than foragers in low density blocks. This increased time spent on a branch helps to explain why a doubling of honey bee colonies generally did not result in a doubling of the pollination rate for pairs of orchards. That is, pollination is more likely to occur when pollinators move from branch to branch.
Effects of a Fungicide and Spray Adjuvant on Queen Rearing Success in Honey Bees
Principal Investigator:  Reed Johnson, Ohio State University, 2011
View research publication
​Reed Johnson and Eric Percel, The Ohio State University, studied the effects of queen bee health when exposed to applications of the fungicide Pristine (boscalid and pyraclostrobin) and spray adjuvants (used to increase the efficacy of the active ingredients).  Their research was of particular interest as it analyzed compounds that are not regarded as highly toxic to adult honey bees but have less know effects on immature bees.  The study conclusions have been published in the Journal of Economic Entomology Research in Dec, 2012.  To test the effect of these compounds on queen development a new test was developed in which queens were reared in closed swarm boxes for four days, until capping, with nurse bees fed exclusively on artificially contaminated pollen.  Pollen was treated with several concentrations of Pristine, a spray adjuvant (Break-Thru), the combination of Pristine and spray adjuvant, and the insect growth regulator insecticide diflubenzuron (known for having a toxic effect on immature bees).   Analysis confirmed that diflubenzuron, in conjunction with Pristine or a spray adjuvant, led to substantial reduction in survival of immature queens.  The potential for diflubenzuron toxicity to change in the presence of fungicides and pesticide adjuvants needs further research.
Effects of "Bee-Safe" insecticides and Common Insecticide-Fungicide combinations on Queen and Worker Larval Development
Principal Investigator:  Reed Johnson, Ohio State University, 2013
Reed Johnson, The Ohio State University, will continue his research to further the information gleaned by his previous study on the effects of insecticides applied to almonds during bloom to developing honey bees. As insecticide use continues to grow, more research is needed to assess the effects of insecticides on colony health. The research study will focus a majority of the effort on diflubenzuron (Dimilin 2L), as this insecticide is the most widely used during almond bloom and has documented potential to harm bee development. The team will also research the effects of high concentrations of methoxyfenozide (Intrepid 2F) and chlorantraniliprole (Altacor), to determine their potential to affect the development of bees. Tests will be conducted on these insecticides and combinations on queen larval rearing and worker larval rearing success.
Watch related video:  Chemtura discusses BMPs for Dimilin Use
​Petal Fall As an Estimator of Almond Bloom
Principal Investigator:  Dr. Frank Eischen, USDA, 2014
​Growers and beekeepers can use petal fall to estimate almond bloom. During 2013 and 2014, we counted the number of new blossom openings daily on a sampling of trees in an early and late blooming almond orchard.  Arrays of buckets were placed under the tree canopy and in the aisles between tree rows.  Petals falling into the buckets were counted daily throughout the bloom cycle.  These numbers were converted to flowers. New flower opening and petal fall was positively correlated. Variation in petals/bucket by position was low across the orchard, the error ranged from 1.5 – 3.2%.  This indicates that a grower wishing to know bloom density could count petal fall in as little as one bucket per variety and have a fairly accurate estimate.  Windy/poor weather conditions might affect this in ways we have not measured.  This data also allows a refinement of the daily shift in the blossom-to-bee ratio during pollination and the amount of pollen/nectar available for bees.  (manuscripts submitted for publication)

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