Culprit Found For Honeybee Deaths In California Almond Groves

PHYS.ORG   By Misti Crane     February 4, 2019

Credit: CC0 Public Domain

Credit: CC0 Public Domain

It's about time for the annual mass migration of honeybees to California, and new research is helping lower the chances the pollinators and their offspring will die while they're visiting the West Coast.

Each winter, professional beekeepers from around the nation stack hive upon hive on trucks destined for the Golden State, where February coaxes forward the sweet-smelling, pink and white blossoms of the Central Valley's almond trees.

Almond growers rent upwards of 1.5 million colonies of honeybees a year, at a cost of around $300 million. Without the bees, there would be no almonds, and there are nowhere near enough native bees to take up the task of pollinating the trees responsible for more than 80 percent of the world's almonds. The trouble was, bees and larvae were dying while in California, and nobody was sure exactly why. The problem started in adults only, and beekeepers were most worried about loss of queens.

Then in 2014, about 80,000 colonies—about 5 percent of bees brought in for pollination—experienced adult bee deaths or a dead and deformed brood. Some entire colonies died.

With support from the Almond Board of California, an industry service agency, bee expert Reed Johnson of The Ohio State University took up the task of figuring out what was happening. Results from his earlier research had shown that some insecticides thought safe for bees were impacting larvae. Building on that, Johnson undertook a new study, newly published in the journal Insects, that details how combinations of insecticides and fungicides typically deemed individually "safe" for honeybees turn into lethal cocktails when mixed.

Johnson, an associate professor of entomology, and his study co-authors were able to identify the chemicals commonly used in the almond groves during bloom because of California's robust and detailed system for tracking pesticide applications. Then, in a laboratory in Ohio, they tested combinations of these chemicals on honeybees and larvae.

In the most extreme cases, combinations decreased the survival of larvae by more than 60 percent when compared to a control group of larvae unexposed to fungicides and insecticides.

"Fungicides, often needed for crop protection, are routinely used during almond bloom, but in many cases growers were also adding insecticides to the mix. Our research shows that some combinations are deadly to the bees, and the simplest thing is to just take the insecticide out of the equation during almond bloom," he said.

"It just doesn't make any sense to use an insecticide when you have 80 percent of the nation's honeybees sitting there exposed to it."

The recommendation is already catching on and has been promoted through a wide array of presentations by almond industry leaders, beekeepers and other experts and has been included in the Almond Board's honeybee management practices. Many almond growers are rethinking their previous practices and are backing off insecticide use during almond bloom, Johnson said.

That's good news for bees, and doesn't appear to be harming the crops either, he said, because there are better opportunities to control problematic insects when almonds are not in bloom.

"I was surprised—even the experts in California were surprised—that they were using insecticides during pollination," Johnson said.

While these products were considered "bee-safe," that was based on tests with adult bees that hadn't looked into the impact they had on larvae.

"I think it was a situation where it wasn't disallowed. The products were thought to be bee-safe and you've got to spray a fungicide during bloom anyway, so why not put an insecticide in the tank, too?"

Insecticides are fairly inexpensive, but the process of spraying is labor-intensive, so growers choosing to double up may have been looking to maximize their investment, he said.

"The thing is, growers were using these insecticides to control a damaging insect—the peach twig borer—during this period, but they have other opportunities to do that before the bees enter the almond orchards or after they are gone," Johnson said.

This research could open the door to more study of fungicide and pesticide use on other bee-dependent crops, including pumpkins and cucumbers, Johnson said.

Explore further: Almond-crop fungicides a threat to honey bees

More information: Andrea Wade et al, Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults, Insects (2019). DOI: 10.3390/insects10010020

Provided by: The Ohio State University

https://phys.org/news/2019-02-culprit-honeybee-deaths-california-almond.html

Pollination Conservation in Cities with Kevin Matteson

Ohio State University     Octoer 18, 2017

Pollinator Conservation in Cities webinar, recorded 10/18/2017 (63m)

http://u.osu.edu/beelab/pollinator-conservation-in-cities-with-kevin-matteson/

Matteson OSU Webinar_2017 PDF handout

Join Ohio State University’s next month's webinar: November 15 at 9AM Eastern/6AM Pacific
Bee City USA & Bee Campus USA: Making the World Safer for Pollinators
Phyllis Stiles, Founder & Director, Bee City USA & Bee Campus USA

For more info: http://u.osu.edu/beelab/

Spatial and Taxonomic Patterns of Honey Bee Foraging: A Choice Test Between Urban and Agricultural Landscapes (Journal of Urban Ecology)

Ohio State University  By Denise Ellsworth   February 16, 2017

The health of honey bee colonies cannot be understood apart from the landscapes in which they live. Urban and agricultural developments are two of the most dramatic and widespread forms of human land use, but their respective effects on honey bees remain poorly understood. Here, we evaluate the relative attractiveness of urban and agricultural land use to honey bees by conducting a foraging choice test. Our study was conducted in the summer and fall, capturing a key portion of the honey bee foraging season that includes both the shift from summer- to fall-blooming flora and the critical period of pre-winter food accumulation. Colonies located at an apiary on the border of urban and agricultural landscapes were allowed to forage freely, and we observed their spatial and taxonomic foraging patterns using a combination of dance language analysis and pollen identification. We found a consistent spatial bias in favor of the agricultural landscape over the urban, a pattern that was corroborated by the prevalence in pollen samples of adventitious taxa common in the agricultural landscape. The strongest bias toward the agricultural environment occurred late in the foraging season, when goldenrod became the principal floral resource. We conclude that, in our study region, the primary honey bee foraging resources are more abundant in agricultural than in urban landscapes, a pattern that is especially marked at the end of the foraging season as colonies prepare to overwinter. Urban beekeepers in this region should, therefore, consider supplemental feeding when summer-blooming flora begin to decline. (Full paper here.)

Douglas B. Sponsler, Emma G. Matcham, Chia-Hua Lin, Jessie L. Lanterman, Reed M. Johnson

https://u.osu.edu/thebuzz/2017/02/16/spatial-and-taxonomic-patterns-of-honey-bee-foraging-a-choice-test-between-urban-and-agricultural-landscapes-journal-of-urban-ecology/

How DNA and a Supercomputer Can Help Sustain Honey Bee Populations

Science Daily   Source: Botanical Society of America   November 13, 2015

New multi-locus metabarcoding approach for pollen analysis uncovers what plants bee species rely on

To uncover what plants honey bees rely on, researchers from The Ohio State University are using the latest DNA sequencing technology and a supercomputer. They spent months collecting pollen from beehives and have developed a multi-locus metabarcoding approach to identify which plants, and what proportions of each, are present in pollen samples.

A single beehive can collect pollen from dozens of different plant species, and this pollen is useful evidence of the hive's foraging behavior and nutrition preferences.

"Knowing the degree to which certain plants are being foraged upon allows us to infer things like the potential for pesticide exposure in a given landscape, the preference of certain plant species over others, and the degree to which certain plant species contribute to the honey bee diet," says graduate student Rodney Richardson. "One of the major interests of our lab is researching honey bee foraging preferences so we can enhance landscapes to sustain robust honey bee populations."

For Richardson and his colleagues, metabarcoding is key to this research. It is a DNA analysis method that enables researchers to identify biological specimens.

Metabarcoding works by comparing short genetic sequence "markers" from unidentified biological specimens to libraries of known reference sequences. It can be used to detect biological contaminants in food and water, characterize animal diets from dung samples, and even test air samples for bacteria and fungal spores. In the case of pollen, it could save researchers countless hours of identifying and counting individual pollen grains under a microscope.

Richardson and his colleagues devised the new metabarcoding method using three specific locations in the genome, or loci, as markers. They found that using multiple loci simultaneously produced the best metabarcoding results for pollen. The entire procedure, including DNA extraction, sequencing, and marker analysis, is described in the November issue of Applications in Plant Sciences.

To develop the new method, the researchers needed a machine powerful enough to process millions of DNA sequences. For this work, the team turned to the Ohio Supercomputer Center.

"As a researcher, you feel like a kid in a candy store," Richardson says. "You can analyze huge datasets in an instant and experiment with the fast-evolving world of open source bioinformatics software as well as the vast amount of publicly available data from previous studies."

In previous metabarcoding experiments, the researchers worked solely with a marker found in the nuclear genome called ITS2. ITS2 successfully identified plant species present in pollen samples, but it could not produce quantitative measurements of the proportions of each.

While searching for something better, they decided to test two markers from the plastid genome. Pollen was previously thought to rarely contain plastids, but recent studies showed promise for plastid-based barcoding of pollen. Richardson and his colleagues found that the combined data from the two plastid markers, rbcL and matK, successfully correlated with microscopic measurements of pollen abundance.

The new multi-locus metabarcoding method involves all three markers and could serve as a valuable tool for research on the native bee species that comprise local bee communities.

"With a tool like this, we could more easily assess what plants various bee species are relying on, helping to boost their populations as well as the economic and ecological services they provide to our agricultural and natural landscapes." Richardson says, "While the honey bee is seen as our most economically important pollinator, it's only one of several hundred bee species in Ohio, the vast majority of which are greatly understudied in terms of their foraging ecology."

Read at: http://www.sciencedaily.com/releases/2015/11/151113144542.htm

Corn Dust Research Consortium (CDRC) Calls for Cooperative Measures to Support Honey Bees, Beekeepers, and Farmers

Bee Culture's CATCH THE BUZZ by Kim Flottum   1/30/14

R. Thomas (Tom) Van Arsdall, Director of Public Policy

The non-profit Pollinator Partnership (P2) today released the 2013 Preliminary Report and Provisional Recommendations of the Corn Dust Research Consortium (CDRC), a multi-stakeholder initiative formed to fund research with the goal of reducing honey bee exposure to fugitive dust emitted from planter fan exhaust during mechanical planting of treated corn seed. The report can be found at http://www.pollinator.org/PDFs/CDRCfinalreport2013.pdf with provisional recommendations starting on page 23.

The CDRC participating organizations include the American Seed Trade Association, the American Honey Producers Association, the American Beekeeping Federation, the Association of Equipment Manufacturers, Bayer CropScience, the Canadian Honey Council, the Farm Equipment Manufacturers Association, the National Corn Growers Association, the Pollinator Partnership, Syngenta, and the University of Maryland. These organizations came together to fund and oversee research projects in 2013 to better understand ideas for mitigating risks to honey bees from exposure to fugitive dust emitted from fan exhaust from machinery during corn planting.

The CDRC funded three research teams, led by Dr. Reed Johnson of Ohio State University, Dr. Mary Harris of Iowa State University, and Dr. Art Schaafsma, University of Guelph on behalf of the Grain Farmers of Ontario. It is hoped that the preliminary results and provisional recommendations will inform best practices for the 2014 planting season. Additional research in subsequent seasons will be needed to replicate and...

Read more at: http://home.ezezine.com/1636/1636-2014.01.30.16.10.archive.html

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