2019NYS Beekeeper Tech Team Report

2019 NYS Beekeeper Tech Team Report

Copyright © 2020 NYS Beekeeper Tech Team. All rights reserved.

March 4, 2020

https://pollinator.cals.cornell.edu

NYS Beekeeper Tech Team

Emma Mullen / ekm75@cornell.edu

Connor Hinsley / cah354@cornell.edu

Travis Grout / travis.grout@cornell.edu

Scott McArt / shm33@cornell.edu

Joan Mahoney / joan.mahoney@agriculture.ny.gov

How to Cite this Report

Hinsley, C. A., L. Figueroa, T.A. Grout, J. Mahoney, S. H. McArt, and E. K. Walters. 2020. 2019 New York State Beekeeper Tech Team Report, 26 pp.

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New York State Beekeeper Tech Team Overview

The New York State (NYS) Beekeeper Tech Team was created in response to unsustainable colony losses across the state in recent years. The Tech Team works closely with New York beekeepers to improve honey bee health, reduce colony losses, and increase the profitability and viability of beekeeping businesses. The Tech Team meets with participating beekeepers several times a year to conduct applied research and to provide information and recommendations that address beekeeping or business challenges. Participants manage operations that range in size from a few backyard hives to thousands of colonies. They remain enrolled in the Tech Team program for up to three years.

The program is funded by the New York State Environmental Protection Fund. It is implemented by Cornell University in collaboration with the New York State Department of Agriculture and Markets.

Tech Team Members

Emma Mullen As the Senior Honey Bee Extension Associate at Cornell University, Emma is the Senior Lead of the NYS Beekeeper Tech Team, overseeing all aspects of the program including administration, data collection, report writing, and communications. She received a Master of Science degree from Western University, Canada, where she studied honey bee social behavior. Emma is passionate about communicating scientific research to beekeepers and working with them to implement best management practices.

Travis Grout As the Agricultural Economic Analyst for the Tech Team, Travis coordinates the Financial Analysis and Business Benchmarking (FABB) program for beekeepers. He received a Master of Science degree in Applied Economics from Cornell University and is focused on the financial health of New York’s beekeeping businesses. Through FABB, Travis works with beekeepers to evaluate their businesses, track performance, and identify areas for improvement, based on the premise that basic business tools can make beekeeping more rewarding for operations of any size.

Connor Hinsley As the Technician for the Tech Team, Connor manages logistics of Tech Team operations, including sampling honey bee colonies in the field and drafting reports. He received a Bachelor of Science degree from Cornell University, where he studied Entomology. Connor is interested in addressing the challenges faced by both honey bees and native bees by helping beekeepers implement practical, evidence-based strategies to reduce the spread of disease and the overuse of chemical treatments.

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Joan Mahoney As the NYS Apiculturist, Joan represents the Department of Agriculture and Markets on the Tech Team. She is an experienced beekeeper, horticulturalist, and program manager. She leads the NYS Apiary Inspection Program, which improves bee health by inspecting beekeeping operations, certifying colonies to cross state lines, and eradicating diseased colonies. She is key to advancing New York’s apiary industry and the goals outlined in the pollinator protection plan. Joan collaborates with the National Honey Bee Survey to evaluate parasite, pathogen, and pesticide prevalence in NYS and

investigate ways to reduce colony losses.

Scott McArt As an Assistant Professor of Pollinator Health at Cornell University, Scott assists in coordinating Tech Team research design and communicating results. Research in the McArt lab focuses on the impact of pesticides, pathogens, and habitat on honey bees and wild bees. He is particularly interested in scientific research that can inform management decisions by beekeepers, growers, and the public.

PhD Candidate Laura Figueroa conducted statistical analyses of the Tech Team data for this report. As a PhD candidate in Dr. Scott McArt’s lab, Laura investigates how pathogens are transmitted among pollinators in complex plant-pollinator networks.

Acknowledgements The Tech Team is grateful for our close collaboration with the Bee Informed Partnership (BIP). We appreciate the advisory support from Executive Director Karen Rennich, as well as Heather Eversole, Andrew Garavito, and Dan Wyns, who together aided in sampling colonies and communicating with beekeepers. The University of Maryland Honey Bee Lab provides parasite diagnostic services for our team. We are grateful to the Empire State Honey Producers Association for supporting and promoting the Tech Team. Lastly, it has been a pleasure to work with members of our Beekeeper Advisory Board, who help to shape the direction and priorities of the Tech Team. We appreciate the contributions of Advisory Board members Chris Cripps, Christina Wahl, Chuck Kutik, Dan Winters, Earl Villecco, Mark Berninghausen, and Pat Bono.

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Executive Summary

This year the Tech Team program experienced a big turnover in participants. Twenty new members enrolled in 2019 and 29 graduated. This change in cohort allows us to compare the impact of the program over time and to expand our education to new beekeepers across New York.

The 23 beekeepers that responded to our survey harvested 318,561 pounds of honey, which comprises 11% of the approximately 3 million pounds of honey the industry produces annually. This value of honey is estimated at $600,000 and the total value of all production for these beekeepers is nearly $1.2 million. Honey continues to be the primary income source for these participating beekeepers, followed by selling nucleus colonies and then providing pollination services. These beekeepers managed 9,668 honey bee colonies, representing 12% of the estimated 80,000 colonies kept in New York.

Over the past three years, annual colony losses have reduced each year from 51% in 2016/2017, to 41% in 2017/2018, to 38% in 2018/2019. Moreover, more than half of all beekeepers’ (58%; 15 out of 26) colony losses reduce or remain constant throughout their time in the program. When we control for year, we see a trend of colony losses reducing throughout beekeepers’ participation in the Tech Team program, with beekeepers in their second year of the program losing 55% of their colonies, and those in the third and fourth year of the program losing 33%. However, this trend is not statistically significant.

Beekeepers improve their colony health throughout their time spent in the Tech Team program. Those in the final year of the program have significantly fewer colonies with high Varroa levels compared to those in the first year of the program. Similarly, the incidence of Parasitic Mite Syndrome declines significantly over time spent in the Tech Team program. This suggests that beekeepers are improving their Varroa management over time and are better able to prevent severe infestations. We recommend beekeepers treat colonies every time they reach or exceed treatment thresholds. Beekeepers who do not use treatments have significantly more colonies with high Varroa levels in autumn compared to beekeepers who applied at least one treatment throughout the year.

Nosema ceranae is a prevalent parasite in New York colonies in spring, but most infections resolve on their own by autumn without treatment. Significantly fewer colonies that are infected in spring have Nosema spores in autumn, and significantly fewer colonies have a severe infection above 1 million spores/bee. From 2017 to 2019, 93.1% of colonies that had high Nosema infections reduced their spore load to a healthy level by autumn of that same year, and 39.8% of colonies eliminated the infection entirely.

European foulbrood incidence was significantly higher in 2019 compared to previous years. Twice as many colonies were infected in 2019 (10.4%) compared to fewer than 5% in all previous years. Beekeepers should inspect colonies for this infection every spring and should manage the disease accordingly.

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Table of Contents Overview ............................................................................................................................................................................. 1

Tech Team Members ....................................................................................................................................................... 1

Executive Summary........................................................................................................................................................ 3

TABLE OF CONTENTS ...................................................................................................................................................... 4

Introduction ...................................................................................................................................................................... 5

Methods .............................................................................................................................................................................. 6

BEEKEEPER PARTICIPANTS .............................................................................................................................................. 6 COLONY SAMPLING ......................................................................................................................................................... 6 LABORATORY ANALYSES .................................................................................................................................................. 8

Varroa ......................................................................................................................................................................... 8 Nosema ....................................................................................................................................................................... 8

BEEKEEPER MANAGEMENT SURVEY ............................................................................................................................... 9

Industry Overview ........................................................................................................................................................ 10

HONEY PRODUCTION .....................................................................................................................................................10 ADDITIONAL HIVE PRODUCTS........................................................................................................................................10 NUCLEUS COLONIES & QUEENS....................................................................................................................................10 POLLINATION SERVICES .................................................................................................................................................. 11

Colony Losses .................................................................................................................................................................. 11

Colony Health .................................................................................................................................................................. 13

VARROA MITES ................................................................................................................................................................ 13 PARASITIC MITE SYNDROME .......................................................................................................................................... 15 NOSEMA ........................................................................................................................................................................... 18 BROOD DISEASES & INSECT PESTS ................................................................................................................................ 19

Deformed Wing Virus ........................................................................................................................................... 20 Small Hive Beetle ................................................................................................................................................... 20 European Foulbrood ............................................................................................................................................... 21 Chalkbrood................................................................................................................................................................ 21 Sacbrood ................................................................................................................................................................... 22 Idiopathic Brood Disease Syndrome ................................................................................................................. 22 Wax Moth ................................................................................................................................................................ 22 American Foulbrood .............................................................................................................................................. 22

Conclusions ..................................................................................................................................................................... 23

REFERENCES ................................................................................................................................................................... 24

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Introduction

Honey bees in New York State face more challenges than ever before, and colony losses continue to occur at unsustainable rates. Between 42% and 68% of New York’s colonies have died each year since 20101. Parasites, viruses, pesticides, nutrition, and management practices all shape honey bee health outcomes. The complexity of factors that influence colony health and productivity makes it difficult for beekeepers to diagnose specific health problems in their colonies and respond appropriately.

Reliable information on colony health and performance empowers beekeepers to make informed management decisions. Knowing Varroa mite levels, Nosema spore counts, and pesticide residues takes the guesswork out of identifying issues with incomplete information. Coupling these data with resources and expert recommendations allows beekeepers to proactively manage their operations using effective, evidence-based practices. The NYS Beekeeper Tech Team was founded to foster this approach.

The Tech Team works with beekeepers across New York State, inspecting a sample of colonies from each participating operation. In the process, the Tech Team documents parasite infestations, pathogen levels, pesticide residues, and management practices of individual hobbyist, sideliner, and commercial beekeepers. Each beekeeper receives a detailed colony health snapshot of their own operation, along with values from similar operations for comparison. Recommendations based on individual test results inform production decisions and support proactive planning for improved pest, disease, and pesticide management. Sharing this information with beekeepers is critical to mitigating colony losses and enhancing the stability and profitability of the New York State beekeeping industry.

The main objectives of this report are to 1) present results from the 2019 Tech Team research that investigates colony health and beekeeper management practices; 2) compare results from 2019 with those from previous years to identify trends over time, where such comparisons are appropriate; and 3) interpret results and identify major findings to support decision making for improved management and colony health. Results and major findings regarding pesticide residues in wax will be presented in a future publication.

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Methods

The Tech Team sets out twice annually, in June and September, to sample colonies across New York State from operations ranging in scale from a handful of colonies to thousands of colonies. Our aim is to provide information useful to hobby (fewer than 50 colonies), sideliner (50 to 499 colonies), and commercial (500 or more colonies) beekeepers throughout the state, and to broadly assess trends and effective managements practices being employed across different operation scales.

Beekeeper Participants Twenty-eight beekeepers participated in the Tech Team program in 2019. Seven were hobbyists, 11 were sideliners, and were 10 commercial beekeepers. This year marked a big turnover in the cohort of participants, as 20 participants joined and 29 graduated. Beekeepers are enrolled in the program on a first come, first served basis. Every year the Tech Team strives for one third of participation to be commercial beekeepers. Participants must 1) keep colonies in NYS, 2) be open to adopting our management practices and recommendations, 3) bring in at least $1000 in revenue annually through their beekeeping business, and 4) be open to participating in the Financial Analysis and Business Benchmarking arm of the program. Participation in subsequent years is conditional on the beekeeper completing their annual management practices survey and annual one-on-one meeting.

Colony sampling In 2019, the Tech Team sampled 269 colonies. We sampled up to 4 colonies in a single apiary from each hobby and sideliner operation, and 10 colonies per apiary were sampled from 2 apiaries from each commercial operation. Whenever possible, colonies that were sampled in 2018 were sampled again in 2019. In both June and September, each colony was inspected to assess the queen status, population strength, brood health, and to collect Varroa, Nosema, and pesticide samples. At least four brood frames were inspected in each colony. We sampled a representative of the apiary, selecting colonies of varying size, strength, and disease load. Every colony sampled is given a unique alphanumeric colony ID. In the event a colony dies or is lost between sampling periods, the ID of the colony is recorded along with its estimated time and cause of death, and a new queenright colony is sampled in its place.

To provide more accurate population estimates for Varroa and Nosema, we collected approximately 300 bees from brood frames in every colony and shipped them to the Beltsville Bee Lab in Maryland. The bees and Varroa mites in the sample were counted to calculate the mite population as a percentage of the honey bee population in that colony. From this sample, 100 worker bee abdomens were removed and the gut contents were viewed through a microscope on a hemocytometer to estimate the average number of Nosema spores per bee.

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If American or European foulbrood symptoms were observed, a Vita test kit was used to verify the infection. If the colony tested positive for American foulbrood, the state apiculturist was contacted immediately in compliance with New York State apiary laws, and the Tech Team mailed a brood sample to the USDA Beltsville Bee Lab.

In September, we collected wax from 2 colonies from each apiary to quantify pesticide residues. These samples are analyzed using Liquid Chromatography Mass Spectrometry (LC-MS) and report pesticide residues in parts per billion. The results of this sampling will be available in a future publication.

We recognize the variability of floral resource availability, weather, and other factors beyond beekeepers’ control vary between counties and region, and as such, we sample colonies across the state. The 269 colonies sampled in 2019 are spread across 7 regions and 20 counties of New York State. The geographical distribution of beekeepers sampled in 2019, as illustrated in Figure 1, is categorized by region as defined by the New York State Department of Economic Development.

Figure 1. The number of Tech Team participants in each NYS region.

Of beekeepers on the Tech Team, 5 manage apiaries in Western New York representing 20 (7.4%) colonies sampled, 8 in the Finger Lakes region of New York representing 80 (29.7%), 5 in the Southern Tier representing 20 (7.4%) colonies, 1 in Central New York, 4 in the North Country region of New York, 4 in the Mohawk Valley, and for the first time, 1 beekeeper in the Capital District of New York. As the program grows, we will be looking to expand into the Hudson Valley, New York City, and Long Island in future years.

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Of the colonies managed by beekeepers enrolled in the Tech Team program, 207 (1.2%) were located in Western New York, 2144 (36.5%) in the Finger Lakes, 196 (3.3%) in the Southern Tier, 70 (1.2%) in Central New York, 4763 (16.4%) in the North Country, and 2288 (39%) in the Mohawk Valley (Figure 2). This difference between the distribution of colonies in 2017 and 2018 and the distribution of colonies in 2019 is largely due to the transition to a new cohort of beekeepers this year.

Figure 2. The number of colonies managed by participating beekeepers, separated by region and year.

Laboratory Analyses

Varroa Approximately 300 bees were collected from the brood nest of each colony in June and September and shipped in a saturated saline solution to the University of Maryland Honey Bee Lab. At the lab, the samples were shaken and washed to dislodge mites from the bees’ bodies. A technician counted the number of bees and mites in each sample and calculated the exact number of mites per 100 bees.

Nosema One hundred worker bees were reserved from the Varroa sample. These bees were crushed to release Nosema spores from their guts. The crushed sample was mixed with 100 mL of deionized water, and 4 μl of the resulting solution was pipetted onto a

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hemocytometer. Using a microscope with 400x magnification, a technician counted spores covering an area equal to 20% of the hemocytometer. This count was converted to the number of millions of spores per bee.

Beekeeper Management Survey All participating beekeepers received a comprehensive survey covering production, management practices, colony losses, and operation characteristics. At the time of printing this report, a total of 23 beekeepers completed the survey, resulting in an 82% response rate. In addition, the beekeeper surveys from 2016, 2017, and 2018 were included for comparison.

Responses to the survey help explain trends in colony health outcomes documented by technicians in the spring and autumn. They also allow beekeepers to evaluate how their colony health, product prices, gross production, and disease management practices compare to averages.

Figure 3. Percent breakdown of total 2019 beekeeper revenue from colony products and services. Shown above in order of revenue generated are honey, nucleus colonies, pollination services, cut comb honey, beeswax products, and other (queens, packages, and pollen).

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Industry Overview

The 23 respondents to the 2019 Beekeeper Management Survey managed a total of 9,668 colonies in 2019, representing 12% of the estimated 80,000 colonies kept in New York State1. These respondents harvested over 300,000 pounds of honey, which comprises 11% of the approximately 3 million pounds of honey the industry produces annually2. The value of their honey is approximately $600,000, and the total value of all production for these beekeepers, including honey, other apiary products, nucleus colonies (“nucs”), queens, and paid pollination services, is nearly $1.2 million. Honey is the main source of revenue for beekeepers enrolled in the Tech Team program, followed by nucs, pollination services, and additional hive products and value-added products (Figure 3).

Honey Production Survey respondents harvested 318,561 pounds of honey in 2019, valued at approximately $600,000 (Table 1). The average yield of 61.25 pounds per colony was not quite as high as in 2016 (64 pounds per colony), but it was higher than in 2017 (52 pounds per colony) and 2018 (49.59 pounds per colony), suggesting 2019 was a good year for honey production.

Additional Hive Products Table 1 illustrates the amount of other apiary products harvested and the total revenue beekeepers received in 2019 from selling these products.

Table 1. Hive products harvested from colonies managed by Tech Team beekeepers in 2019, including total volume harvested, average harvested per colony, and the total estimated revenue generated by sales of these hive products.

Colony Product

Total Colonies

Total Harvested

Average Per Colony

Total Revenue

Honey 11,564 318,561 lb 61.25 lb $ 595,788.40

Cut Comb Honey 213 6,213 units 29.69 units $ 45,678.35

Beeswax 3,590 2,884 lb 1.19 lb $ 20,857.50

Pollen 2 4 lb 2 lb $ 12.00

Propolis 53 3.5 lb 0.26 lb N/A

Nucleus Colonies & Queens A total of 8 operations (35%) sold nucs in 2019. The average sale price was $156.88 per nuc, and the total value of nucs produced by survey respondents was $307,000.00. Three operations (13%) produced queens for sale in 2019. The average sale price was $30.00 per queen, and the total value of queens produced by survey respondents was $4,150.00.

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Pollination Services Seven survey respondents (30%) sent 2,430 colonies into commercial pollination for 5 agricultural crops across 3 states in 2019. Table 2 shows the number of colonies sent to pollinate each crop, the state where pollination occurred, the average reported price per colony, and the estimated revenue. The total value of pollination services provided by Tech Team participants in 2019 was $225,090.00.

Table 2. Reported pollination services in 2019.

Crop Pollinated

Colonies in Pollination

State Average Price Per Colony

Estimated Total Revenue

Blueberry 1500 NJ $ 100.00 $ 150,000.00

Apple 818 NY $ 74.17 $ 60,890.00

Almond 60 CA $ 150.00 $ 9,000.00

Melon 40 NJ $ 100.00 $ 4,000.00

Cherry 12 NY $ 100.00 $ 1,200.00

Colony Losses

High colony losses are a major concern and management challenge for beekeepers in New York State. The Tech Team calculates winter, summer, and annual colony losses. Winter losses cover the period from October 1, 2018 to April 1, 2019; summer losses cover the period from April 1, 2019 to October 1,2019; and annual losses cover the period from October 1, 2018 to October 1, 2019. For a given period, the loss rate is calculated as the total number of colonies that died in the period divided by the total number of colonies kept during that period, using the method established by the Bee Informed Partnership3.

Figure 4 shows total winter, summer, and annual colony losses for 23 beekeepers that completed the 2019 NYS Beekeeper Tech Team Management Survey. In 2019, winter loss was 33.1% (3,401 out of 10,275 colonies) and summer was 17.7% (1,778 out of 10,042 colonies). The total annual loss rate for the 2018-2019 year was 38% (5,201 out of 13,513 colonies). These are the lowest losses recorded since the Tech Team program began, but they are still 1.8 times greater than the loss rate that beekeepers considered acceptable (21%). The Tech Team strives to help beekeepers lower their colony losses over time. Over the past three years, colony losses have indeed reduced each year (Figure 5a): in 2016/2017, total colony losses were 52% (13,069 out of 25,530); in 2017/2018, they were 41% (10,777 out of 26,522); and in 2018/2019, they were 38% (5,201 out of 13,513). More than half of all beekeepers’ (58%; 15 out of 26) colony losses reduce or remain constant over time. Nine (35%) have lost more colonies over time, and two (8%) have fluctuated across years.

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Figure 4. Colony losses in 2019 in winter (October 1 – April 1), summer (April 1 – October 1), and annually (October 1 – October 1). The solid teal line indicates the average percent loss beekeepers consider economically sustainable.

When we control for year, we see a trend of colony losses reducing throughout beekeepers’ participation in the Tech Team program, with beekeepers in their second year of the program losing 55% of their colonies, and those in the third and fourth year of the program losing 33%. However, this trend is not statistically significant (P=0.4825; Figure 5b). Additionally, neither winter losses nor summer losses were significantly different based on how long beekeepers have been enrolled in the Tech Team program (P=0.604 and P=0.689, respectively.) It is noteworthy that 74% of all beekeepers in “Year 1” of the program began in 2019. Data from beekeepers who started in 2016 were excluded from this analysis because we did not accurately capture colony losses in 2015/2016. This makes it challenging to meaningfully compare improvements from Year 1 to subsequent years in this report.

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Figure 5. Annual colony losses have reduced each year since 2016/2017 (a), but they are not predicted by the beekeeper’s time spent in the Tech Team program (b).

Colony Health

Varroa Mites

Varroa mites (Varroa destructor) are the most damaging parasite of honey bees and are a significant predictor of winter mortality in New York State4. We recommend colonies should be treated every time mite populations exceed 2 mites/100 bees in spring and early summer and 3 mites per 100 bees in late summer and autumn. Beekeepers are encouraged to refer to our Varroa resources on our website (pollinator.cals.cornell.edu) and in their Tech Team Resource Binder to learn about monitoring and Integrated Pest Management options. While levels were well controlled in June, beekeepers struggled to keep them below the treatment threshold in September. This is typical to what we observe in other years4, as mite populations are consistently lower in spring and higher in autumn, typically peaking in October. In September 2019, the average Varroa levels were nearly 7 mites/100 bees, more than twice the treatment threshold (Figure 6). In autumn, 57% of colonies exceeded the treatment threshold. In spring, only 10% did (Figure 7).

Beekeepers in their first year of the Tech Team program have the most colonies with high Varroa levels (56%), and proceeding years have fewer (26% of colonies among second year beekeepers, 44% among third year, and 30% among fourth year). The proportion of colonies that exceed the treatment threshold in autumn vary depending on how long beekeepers have been enrolled in the Tech Team program. Beekeepers in their final year of the program have significantly lower mite levels than beekeepers in the first year of the program (P=0.002; Figure 8).

Year in the program Year

Num

ber

of c

olon

ies

Tot

al c

olon

y lo

ss (%

)

Colonies

Lost

Survived

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Figure 6. Spring and autumn Varroa levels in 2019.

Figure 7. Percent of colonies above the treatment threshold in spring (2 mites per 100 bees) and autumn (3 mites per 100 bees) 2019.

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Figure 8. The proportion of colonies that exceed the autumn treatment threshold across the beekeepers’ year in the program.

Parasitic Mite Syndrome

Parasitic Mite Syndrome (PMS), also known as Varroa Mite Syndrome, is an advanced stage of Varroa infestation and virus infection. While Varroa levels provide an acute indicator of recent management and treatment choices, PMS reflects the cumulative impact of exposure to Varroa mites and their associated viruses over time. PMS typically manifests during the months of August through November in New York, after mites and viruses have been permitted to build up for several months without effective treatments. Throughout all sampling periods, colonies with PMS had higher Varroa mite levels (10.27 mites per 100 bees, on average) compared to colonies without PMS (2.32 mites per 100 bees, on average).

In 2019, 18% of colonies had PMS. Hobbyist beekeepers had the lowest prevalence of PMS (10.3%). Sideliner beekeepers had the highest prevelence (20%), followed closely by commercial beekeepers (17%; Figure 9). We do not know why PMS is more common in larger operations compared to hobby operations. Possibly colonies from larger operations were exposed to other stress factors that could make them more susceptible to developing PMS.

Year in Program

Prop

orti

on o

f col

onie

s

Varroa level

High Low

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It is also possible that Varroa levels in larger operations simply remained unmanaged for longer periods of time compared to colonies managed by hobbyist beekeepers. As beekeepers participate in the Tech Team program over time, the proportion of colonies with PMS decreased significantly (P=0.001; Figure 10). This suggests that beekeepers are improving their Varroa management over time and are better able to prevent severe infestations.

Figure 9. Percent of colonies exhibiting symptoms of PMS in autumn 2019, broken down by operation scale.

Symptoms of PMS include dead larvae (a), visible Varroa mites (a), a spotty brood pattern (b), chewed-down brood (b), and adult bees with deformed wings (c).

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Figure 10. Proportion of colonies exhibiting PMS across the beekeepers’ year in the program.

Figure 11. Proportion of colonies with high Varroa levels based on whether or not beekeepers applied at least one Varroa treatment.

Year in Program

PMS Presence

Prop

orti

on o

f col

onie

s

Absent Present

Prop

orti

on o

f col

onie

s

Varroa level

High Low

Yes No Applied at least one treatment?

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Last year, we determined the value of treating for Varroa. We found as the number of treatments a beekeeper used throughout the year increased, the Varroa mite levels in autumn significantly decreased4. This year, we continue to report benefits of treatments. Beekeepers who did not use treatments had significantly more colonies with high Varroa levels in autumn compared to beekeepers who applied at least one treatment throughout the year (P=0.046; Figure 11).

Nosema

Nosema disease follows a clear seasonal pattern in New York State; infections are consistently higher in spring and lower in autumn every year (Figure 12). Although some colonies do continue to be infected in autumn, Nosema is not a significant predictor of winter loss4.

Figure 12. Average Nosema levels by sampling period.

Nosema ceranae is a prevalent parasite in New York colonies in spring, but most infections resolve on their own by autumn without any treatments. From 2017 to 2019, 93.1% of colonies that had high Nosema infections (1 million spores/bee or higher) reduced their spore load to a healthy level by autumn of that year. Fully 39.8% of colonies that had any Nosema spores in spring eliminated the infection entirely, such that the spore count was 0 spores/100 bees in autumn. Figure 13 shows that significantly fewer colonies had Nosema spores (P<0.001) and significantly fewer colonies had a severe infection (P=0.001) in autumn compared to the previous spring.

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Figure 13. The number of colonies with Nosema infections, as well as the severity of Nosema infections in spring and autumn from 2017-2019. Colonies with high infections have 1 million spores per bee or greater, those with low infections have fewer than 1 million spores per bee.

Even though most Nosema infections resolve on their own without intervention, it is important for beekeepers to be aware of their levels. If beekeepers observe symptoms of Nosema (e.g., weak population, slow population build-up, reduced honey and brood production), they should monitor. Colonies suffering from Nosema may benefit from supplemental feeding in spring and should be isolated from healthy colonies. Six months later the colony can be monitored again to see if the infection resolved. If the infected colonies die over winter, it is recommended beekeepers disinfect their equipment before introducing new bees by using one of the methods outlined in the Cornell Dyce Lab info sheet “Nosema Disease: information for identification and control in New York”.

Brood Diseases & Insect Pests

In addition to Nosema and Varroa, honey bee colonies are susceptible to insect pests, and brood is susceptible to a variety of viral, fungal, and bacterial infections. The Tech Team observed a variety of issues in colonies that are outlined in Figure 14. The most common issues observed during inspections were deformed wings, followed by small hive beetles, and then European foulbrood.

Season Spring Autumn

Num

ber

of c

olon

ies

Nosema infection

Absent Low

High

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Figure 14. Prevalence of pests and diseases in colonies sampled in spring and autumn 2019.

Deformed wing virus Deformed wings were visually observed in 21.4% of colonies in autumn 2019. Deformed wing virus is the main virus vectored by Varroa mites, so its symptomatic prevalence reflects Varroa loads. The presence of deformed wings suggests that mite levels are high and should immediately prompt the beekeeper to monitor mites and apply a treatment if needed.

Small hive beetle Small hive beetles are a common insect pest in honey bee colonies in New York State. They are opportunistic pests that typically exploit weakly populated colonies. To prevent infestation, beekeepers should maintain healthy colonies with strong populations and only super colonies when the colony population dictates. This pest tends not to kill colonies in New York but may exacerbate the decline of a colony that is already dealing with another pest or pathogen. Small hive beetle incidence is high in autumn, when 10.7% of colonies were infested, and is low in spring with only 4% of colonies were infested. This seasonality of low population in spring and high population in autumn is typical for New York State. The impacts of hive beetle infestation are most often observed when honey supers are not promptly extracted. The Tech Team encourages beekeepers to use beetle traps, Swiffer® pads, or Brawny-Max Towels® to control beetles, and discourages the use of Checkmite+™ and pyrmethrin soil drenches, as these pesticides can negatively impact bee health. Chemical treatments for small hive beetle are sometimes necessary in warmer regions where beetles can reproduce year-round. In more temperate regions with a cold winter, like New York, chemical treatments for small hive beetle should be used only as a last resort.

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European foulbrood European foulbrood (EFB) is another destructive brood disease. The Tech Team observed a total of 53 colonies with EFB across the seven sampling periods, including fourteen colonies in June 2018 and two colonies in September 2018. Of the 53 cases of EFB diagnosed by the Tech Team, 26 were diagnosed across 13 operations in spring 2019. The incidence of EFB in 2019 was significantly higher than in previous years (P<0.001; Figure 15). The unusually widespread occurrence of EFB in spring 2019 may be a result of environmental factors, as it is typically a “stress” disease that manifests in times of poor weather and nutrition. There were no cases of EFB diagnosed in autumn of 2019, as all previously diagnosed colonies either died or recovered through feeding, antibiotics, requeening, and/or bolstering sick colonies with brood from healthy colonies. In some cases, European foulbrood can be difficult to differentiate from other brood diseases. In ambiguous cases, diagnosis can be made by using an EFB Vita test kit or by sending a sample to the USDA Beltsville Bee Lab for a free analysis.

Figure 15. Proportion of colonies with European foulbrood in spring 2016-2019.

Chalkbrood Chalkbrood is a fungal brood disease most prevalent in spring, as it thrives in cool, moist conditions. As colony populations strengthen and weather warms, most chalkbrood infections clear in the summer. It is not regarded as a highly detrimental disease as infections usually clear up in the summer as the temperature rises. If infections do not clear up on their own, requeening (ideally with hygienic stock) may help a colony overcome the infection. If more than 10–20% of brood cells on a single frame are infected, beekeepers should discard those frames and replace them with frames of drawn comb or foundation.

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Sacbrood Sacbrood is managed through proper nutrition and sustaining strong colony populations. In the early stages of infection, bees can prevent a major outbreak by removing diseased larvae through hygienic behavior. If a colony experiences a larger outbreak (with at least 5% of brood cells visibly infected), the beekeeper should discard brood frames that contain many infected cells and requeen the colony, ideally with hygienic stock. There are no treatments for sacbrood.

Idiopathic brood disease syndrome Foulbrood diseases and parasitic mite syndrome can be confused for idiopathic brood disease syndrome (IBDS, also called crud brood or snotty brood). With this syndrome, unhealthy larvae appear “melted” into the bottom of a cell, though the liquefied larvae do not rope out. Although it closely mimics parasitic mite syndrome in appearance, this brood disease is present when there is no evidence of mites in the cells and colony mite levels are low. The causes of IBDS are not yet known, though a variety of viruses may partially contribute. While this syndrome is uncommon, the Tech Team did observe it in 1.6% of colonies in spring 2019.

Wax moth Like small hive beetles, wax moths are a common secondary insect pest in New York State. Although they do not directly cause colony death, wax moths thrive in weak colonies with insufficient population to defend the entirety of the hive body. Adult wax moths and their larvae were only observed in 4 colonies in 2019. Generally, any issue with wax moths in the hive can be solved by strengthening the hive or by reducing the space available in the colony. While they do not pose a threat to colony health, an infestation of wax moths can be devastating to beekeeping equipment. It is recommended that beekeepers freeze their equipment (0°C for 4 days) and/or to store equipment in such a way that the comb are exposed to light throughout the day. Alternatively, storing equipment with para-dichloro-benzene (PDB) crystals according to proper procedure can be a last resort option for more severe infestations, though beekeepers should exercise caution when using this product.

American foulbrood American foulbrood (AFB) is the most contagious and destructive bacterial disease that honey bees can contract. Although zero cases of AFB were diagnosed by the Tech Team in 2019, Joan Mahoney from the NYS Department of Agriculture and Markets reported 114 cases of AFB between 14 beekeepers across 11 counties. It was surprising to learn 29 of these cases were resistant to oxytetracycline. Because prophylactic use of antibiotics is now discouraged, and because antibiotics can only be obtained through a veterinary prescription, it is critical that all beekeepers stay vigilant about inspecting and testing their colonies. They should conduct three careful AFB inspections of every colony each year. Beekeepers must familiarize themselves with proper inspection techniques and learn how to recognize early symptoms of infection. It is the law in NYS to report all infected colonies to the state apiculturist.

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Conclusions

The NYS Beekeeper Tech Team works with beekeepers to improve colony health outcomes by inspecting a sample of their colonies twice a year and by reporting Varroa, Nosema, and pesticide levels for those same colonies. The Tech Team also helps beekeepers interpret their colony health reports and develop research-based management strategies that respond to their individual needs and production goals. This year marked a turnover in Tech Team participants, with 29 beekeepers graduating and 20 new beekeepers joining the program. As a result, 75% of participants were new to the program in 2019.

Following historical trends in production, beekeepers enrolled in the NYS Beekeeper Tech Team program generated most of their revenue selling honey, nucs, and pollination services. Approximately 18.5% more honey was produced per colony in 2019 than in the previous year, which could be reflective of more favorable weather conditions or better management practices. 2019 also saw a smaller percentage of honey-producing colonies started as splits or nucs that same year, which may have also contributed to the increase in average honey production.

Here are the Tech Team’s recommendations based on 2019 industry trends documented in this report:

1. Be vigilant about Varroa management. We recommend adopting an IPM approach, which includes monthly monitoring, using cultural and genetic tools as appropriate, and applying registered treatments every time colonies reach or exceed treatment thresholds. Autumn Varroa levels in 2019 were very high (7 mites/100 bees, on average) and most colonies (57%) exceeded the treatment threshold. This time of year requires diligent management. Treatments are very important tools to ensure colonies have healthy levels entering winter. Over time in the Tech Team program, beekeepers’ colonies become healthier with regards to Varroa, likely because beekeepers are improving their management. The Tech Team is available to help develop mite management plans for beekeepers.

2. Do not use treatments for Nosema in spring. Most colonies resolve their infections on their own by autumn. Consider treatments if autumn levels are still above 1 million spores per bee. If colonies infected with Nosema die over winter, disinfect equipment before installing more bees.

3. Inspect colonies for European foulbrood in spring. Incidence was high in 2019, and it is

not known whether this trend will continue in future years. Use Vita test kits to confirm suspected cases. Manage EFB according to the Dyce Lab info sheet “European Foulbrood: Information for identification and control in NYS”.

4. While the Tech Team did not detect colonies with AFB in 2019, continue to inspect for

this infectious disease, as 114 cases were found in New York State. Use Vita test kits or

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send samples to the USDA Beltsville Bee Lab to confirm suspected cases, and report all confirmed cases to Joan Mahoney at the Department of Agriculture and Markets.

Beekeepers who wish to continue learning about the management and business aspects of beekeeping are encouraged to visit the resources on the Cornell Pollinator Network webpage, www.pollinator.cals.cornell.edu.

References 1. Cappy, P., personal communication. Estimated colonies in New York State. E Mullen.

(2018). 2. United States Department of Agriculture National Agriculture Statistics Service.

New York State honey production data, <https://quickstats.nass.usda.gov> (Accessed Feb 25, 2020 through Quick Stats). Average pounds of honey produced in New York State from 2009 to 2018 is 3.06 million.

3. Kulhanek, K., Steinhauer, N., Rennich, K. & Caron, D. M. A national survey of managed honey bee 2015–2016 annual colony losses in the USA. Journal of Apicultural Research 56, 328-340 (2017)

4. Hinsley, C. A., C. M. Urbanowicz, P. Cappy, T.A. Grout, S. H. McArt and E. K. Mullen. 2019. 2018 New York State Beekeeper Tech Team Report, 27 pp.