A.M.S.L. - Apicultural Notes

1) an abstracted version of a paper reporting research results from the M.Sc. project of Jamie Strange. Jamie found that a single well-timed treatment for Varroa mites in Washington State gives equivalent control to continuous or semi-annual treatments. These results should be highly encouraging to beekeepers who want to minimize exposure of bees and hive products to pesticides. Restricting the application of pesticides to an "as needed" activity is fundamental to protecting the efficacy of these compounds by slowing the develoment of resistance. For a more complete version of Jamie's research you can download a free PDF file of the resulting scientific paper by going to the Journal of Economic Entomology page, http://esa.edoc.com/server-java/Propub/esa/ec-v94n6.contents, and selecting the paper that starts on page 1324.

2) the text of the January 2003 "Research Reviewed" column (Bee Culture magazine 131:17-18). This month the topic concerns the importance of using "controls" in experimental design and the need for all readers to search scientific and popular articles for such elements before believing the old "fish oil" story...

3) a press release from AVA Chemical Ventures reporting the successful EPA registration of a sugar ester (Sucrose Octanoate) and...

4) the U.S. Environmental Protection Agency approved label of the sugar ester, sucrose octanoate, for use on honey bees to control Varroa mites. We have been working with this material for several years to develop suitable application methods and efficacy data. The approval by EPA now opens the door for sale and distribution by interested suppliers. This comes not a moment too soon - as reports from Florida indicate the discovery of mites resistant to both Apistan and Coumaphos. Sucrose octanoate is now being tested on these resistant mites in Florida. Although more labor intensive to use than plastic strips - sucrose octanoate has the advantage of being quite safe to work with and exempt from tolerance. We are preparing a manuscript on the results of our testing with sucrose octanoate and I will report more details on its use in the next Apicultural Notes.

Optimum timing of miticide applications to control Varroa destructor in Washington State

by Jamie Strange and Steve Sheppard

Introduction

Varroa destructor Anderson and Trueman (formerly called V. jacobsoni) is the most serious pest to the beekeeping industry in the United States (Delaplane 1998). V. destructor is an external parasite of capped larval and pupal bees and is phoretic on adult bees. In Apis mellifera L. colonies, mortality from V. destructor infestation can reach 100% in two years if left untreated (De Jong 1990).

Since its detection to the United States in 1987, V. destructor has been controlled almost exclusively with fluvalinate. Apistan¨ strips (tau-fluvalinate) were approved in 1988 and initially showed efficacy of 97%-100% (Watkins 1996). In the United States, fluvalinate resistant mites have been reported for South Dakota (Baxter et al 1998), Florida, and California (Elzen et al 1998). To reduce the selection pressure leading to miticide resistance in V. destructor, we sought to determine the minimum number of applications and the most effective timing for application of fluvalinate in Washington State. Until now, research based treatment recommendations were not available for Washington State. By improving treatment timing, costs can be reduced and the selection pressure for the establishment of fluvalinate resistant mite populations can be decreased (Delaplane 1998, Elzen et al 1999, Caron 1999).

Materials and Methods

We established a research apiary of 56 colonies near Pullman, WA in April 1999. To equalize bee and mite populations, worker bees from 60 over-wintered hives were shaken into a common population cage. Each hive contained approximately 2 frames of brood, 3 frames of honey, one frame of pollen, 2 empty frames, and an internal feeder. The bees were then were divided into 0.9 kg (2 lb.) packages and used to populate the experimental hives. A new queen was introduced into each colony.

The colonies were placed into circles of 8, and each of the seven circles was randomly assigned a treatment to control V. destructor. Fluvalinate was applied using Apistan¨ strips and coumaphos was applied as Checkmite+¨ strips. Prior to each application, all colonies were sampled using 48h sticky boards and ether rolls. All mites trapped on the sticky boards were counted. For the ether roll, mites that were stuck to the sides of the jar were counted.

The evening prior (16+/-4 hours) to each sampling date, 2 colonies from each treatment group were closed. The following day, the colonies were sampled. We measured the weight of the bees in the colony, the capped brood area and determined the percentage of mite infested brood cells. A sample of 150 ml of bees was transported to the laboratory to determine the average bee weight and the number of mites on adult bees. From the data obtained in the field and the lab, we calculated the colony bee population, the colony mite population and the number of mites per 100 bees.

Results and Discussion

In April 2000, no significant differences were found among chemically treated colonies, however all treatments had significantly higher colony bee populations than the untreated control (Figure 1). The area (cm2) of sealed brood cells was significantly different among the treatment groups at the April 2000 sampling date. The colonies receiving a miticide application in October had the highest mean brood area at the April 2000 sampling date and were significantly higher than the control and August treatment (Figure 2).

All of the colonies in treatment groups had lower mite populations than the colonies in the control group at the November 1999 sampling date and at the April 2000 sampling date. In April 2000, the mean mite per 100 bees ratio in the control colonies was 32.5 mites per 100 bees while mean mite levels in all miticide treated colonies remained below 1.7 mites per 100 bees (Figure 3).

Colonies were considered to exceed the damage threshold if the colony bee weight was below the initial colony weight (0.92 kg) one year after the experiment was started (April 2000). The eight control colonies were all below the initial colony weight in April 2000. Colonies treated with fluvalinate in October, fluvalinate in April and October and fluvalinate continuously, had colony bees weights significantly higher than control colonies. Those colonies that received coumaphos or fluvalinate in April, or fluvalinate in August had intermediate colony bee weights that were not statistically different from either group (i.e.control vs Oct. fluvalinate/cont. fluvalinate/April-Oct. fluvalinate).

Integrated pest management (IPM) strategies have been developed for many pest arthropods in production agriculture. These strategies aim to maximize production while limiting the chemical inputs into the management system. A good IPM system for bees should reduce costs, limit chemical use (thereby reducing selection pressure for resistant pests) and result in no more damage to the colony than is seen in a conventional management strategy. By applying a chemical only at the optimum time, these goals are met. However, this is only one step in an IPM strategy that includes the use of non-chemical mite control measures. A single fall application of fluvalinate in honey bee colonies is a feasible strategy for V. destructor control in Washington State When this is done, mite control is equivalent to that achieved using semiannual or continuous treatment. Additionally, this study provides further evidence for the importance of considering regional differences in optimizing treatment timing.

A regular sampling regime combined with a treatment threshold number of mites can be used for both ether roll and sticky board data to reduce pesticide applications to A. mellifera colonies. Implementation of additional IPM strategies such as breeding for resistant stocks of A. mellifera, cultural control, and use of newly registered "soft" chemicals should permit further reductions in fluvalinate and coumaphos use. As more options become available to beekeepers, integrated mite management strategies can be used to manage V. destructor populations below a damage threshold and to maximize the health of A. mellifera colonies.

Figure 1. Mean number of bees per colony in April 2000.

Figure 2. Area of capped brood in April 2000.

Figure 3. Mean number of mites in April 2000.

References

Baxter, J., F. Eischen, J. Pettis, W. T. Wilson, and H. Shimanuki. 1998. Detection of fluvalinate-resistant Varroa mites in U.S. honey bees. Am. Bee J. 138: 291.

De Jong, D. 1990. Mites: Varroa and other parasites of brood, pp. 200-218. In R. A. Morse and R. Nowogrodzki [eds.], Honey bee pests, predators and diseases 2nd edition. Cornell University Press, Ithaca NY. 1990.

Delaplane, K.S. 1998. Varroa control: timing is everything. Am. Bee J. 138: 575-576.

Elzen P. J., J. B. Baxter, F. A. Eischen, and W. T. Wilson 1999. Pesticide resistance in Varroa mites: theory and practice. Am. Bee J. 139: 195-196

Elzen, P. J., F. A. Eischen, J. B. Baxter, J. Pettis, G. W. Elzen, and W. T. Wilson 1998. Fluvalinate resistance in Varroa jacobsoni from several geographic locations. Am. Bee J. 138: 674-676.

Watkins, M. 1996. Resistance and its relevance to beekeeping. Bee World. 77: 15-22.

Acknowledgements - This research was supported in part by the Washington State Commission on Pesticide Registration, the Washington State Beekeepers Association and the WSU Department of Entomology. We are grateful to the Washington State Beekeepers Association and the numerous Washington state beekeepers who donated supplies and honey bee colonies and were very supportive of this project.

This issue marks the beginning of my second year writing “Research Reviewed” and I’d like to take a portion of this month’s column to discuss a common thread found in research papers from scientific journals. That is the use of controlled experiments to test hypotheses. In plain language – it means that researchers have to set-up experiments in ways that allow them (and others) to determine that the effects they measure are due to a given treatment rather than some unknown factor. This is perhaps more easily explained by an example. Imagine a bee meeting where an excellent beekeeper stands up and reports that in the Fall he dipped shop towels in fish oil, placed them in all 2000 of his colonies and found very low levels of Varroa mites in his colonies the following Spring. He argues forcefully that fish oil is a great thing and he will forever use it for Varroa control. What is wrong with the beekeepers conclusion? Actually, based on the design of his “experiment”, we are unable to determine whether the Spring mite levels were low due to the fish oil treatment or any of a number of other factors (weather, bee or mite genetics, low initial mite populations, or an unknown component of the shop towel material itself). Why? Because there were no “controls” for the experiment, i.e. all the colonies received the fish oil “treatment”. Therefore, there is nothing against which to measure the supposed effect. Perhaps the mite levels in those particular colonies in that particular Spring would have been low regardless of the fish oil treatment. However, if the beekeeper had treated 1000 colonies with fish oil+ shop towels and 1000 colonies with shop towels alone and then found a significant difference between the two treatments, he would be on much firmer ground to support the claim of a possible new Varroa treatment. Other beekeepers and researchers could then repeat the experiment to confirm the results; some researchers would begin to look for the active compounds in fish oil and at some point we would all work toward the EPA registration of fish oil.

While the details of the fish oil story are imagined – most of us have heard similar sorts of testimonials at bee association meetings and other gatherings of beekeepers. The fact is – most beekeepers are not interested in publishing scientific papers and do not feel very concerned with setting up controlled experiments. However, as readers of Bee Culture, all of us are faced with evaluating the content of written articles, letters and advertisements. Recognizing the limitations of “research” that does not explicitly describe the controls of the experimental set-up is an important skill that will improve your ability to evaluate fish oil stories. As you read this column in the future, realize also that description of the experiment set-up and the controls are mentioned to provide a basis for which you, the reader, can evaluate the conclusions of the author(s).

Speaking of Varroa – the following are taken from abstracts presented by bee researchers at the 49th meeting of the Association of Institutes for Bee Research in Celle, Germany in March of 2002. These are typically brief reports of ongoing research by the authors, but furnish an interesting glimpse into the topics of interest to European bee researchers.

Varroatosis-disease complex: is there any interrelation? (O. Boecking, P. Aumeier, W. Ritter, D. Wittman.). The authors note that Varroa destructor infestations have often been associated with secondary infections. These authors report the results of 2 years of data collection on 75 Varroa-infested colonies of bees that included high (>1500 mites) and low (<170 mites) infestation levels and 8 distinct genetic strains of bees. They documented the occurrence of symptoms of secondary infections such as sacbrood, Nosema, chalkbrood, American foulbrood spores, tracheal mites, acute paralysis virus (APV) and deformed wing virus (DWV) in relation to the Varroa mite infestation level and genetic origin of the bees. They found no relation between Varroa infestation levels and sacbrood, Nosema or chalkbrood. Tracheal mites and AFB spores were not present. While the presence of deformed wings was correlated to high levels of Varroa mites, there was no relation between Varroa mite levels and DWV or APV. Their conclusion: “The presence of secondary infection of the bee colonies in these investigations was independent of the mite infestation level and genetic origin of the colonies.” The answer to the question posed in the title? No. (Note that AFB is very rare in Germany, where destruction of AFB-infected colonies by burning is the rule and no antibiotic treatments are permitted. Thus, while this experiment found no AFB spores, it did not show that mites could not transmit AFB. See the abstract below).

Do Varroa destructor mites transfer European foulbrood (Melissococcus pluton)? (G. Kanbar, W. Engels, G. Winkelmann). The authors pointed out that Varroa mites that enter a brood cell bite into the larva and pupa to feed and keep the wound open for some time. They used an electron microscope to examine the mite feeding wounds on a number of hosts and reported that 15% of the sites contained a large number of bacteria. These bacteria were identified as M. pluton, the causative agent of European Foulbrood. Spores of this bacterium were also identified on the bodies and mouthparts of the mites and the authors concluded that they were “clearly transferred to honey bee larva…during biting and feeding.” The take home message: in addition to the well-known oral means of foulbrood infection caused by nurse bees feeding larvae, Varroa mites constitute a second route of infection. Thus, the answer to the question posed in the title? Yes.

Mites can tire males: wind tunnel test with Varroa destructor parasitized drones (P. Duay, W. Engels) The authors first note that in Germany one method of Varroa treatment is the use of drone combs to trap the mites. However, this practice results in a diminished population of drones and the remaining drones are likely to be more highly parasitized. In an experiment designed to test the effects of mite parasitism on drone flight capacity, the researchers used a wind tunnel to compare the performance of unparasitized drones to those that had been parasitized by one or two mites. The 12-day old drones were flown “until exhausted” and flight durations were compared. They reported that the parasitized drones flew less than the control (unparasitized) drone group. However, one-third of the drones parasitized by only one mite were able to fly as long as the unparasitized drones and thus might be suitable for mating. The authors caution that they did not yet determine whether the slightly parasitized drones have sufficient sperm or can orientate adequately to the drone congregation areas.

Reference: Association of Institutes for Bee Research Report of the 49th seminar in Celle. 2002. Apidologie 33: 459-519

EPA REGISTERS NEW CLASS OF INSECTICIDE: SUCROSE OCTANOATE ESTERS AVA Chemical Ventures, L.L.C. (“AVA”) has received EPA registration (#70950) for the active ingredient Sucrose Octanoate Esters, a biochemical insecticide/miticide manufactured from sugar and vegetable oil-derived fatty acids. This is the first active ingredient to be registered within the new class of sugar ester chemistry the company is developing. AVA expects to register additional sugar ester active ingredients. Sugar ester insecticides kill rapidly; do not harm major beneficial insects; and break down in the environment to their constituent sugars and fatty acids.

Sucrose Octanoate Esters kill either by rapid suffocation or by removing the insects’ protective coating, causing them to desiccate. Because of the contact mode of action, it has a relatively short residual. Primary target applications are mites, aphids, whiteflies and other soft-bodied insects on fruit and vegetable crops and ornamentals. The EPA registration includes an exemption from tolerance for all food crops. Labels have been approved for foliar spray on outdoor plants; varroa mite control on honey bees; and sciarid fly control in mushroom growing media.

The Sucrose Octanoate Esters active ingredient is synthesized from agricultural raw materials that are both edible and renewable. Its origins can be traced to the early 1990’s, when scientists at the Agricultural Research Service (ARS) of the U. S. Department of Agriculture discovered that sugar esters occurring naturally in the leaf hairs of wild tobacco acted as natural insecticides. It was not possible to extract the naturally-occurring sugar esters in sufficient quantity to be commercially viable. AVA overcame this problem by developing viable sugar ester synthesis processes based on sugars and vegetable oil fatty acids.
AVA holds patents covering the manufacture and insecticidal use of sugar esters, including U.S. patent # 6,419,941, “Polyol Ester Insecticides and Method of Synthesis,” issued July 16, 2002. Additional patents on pesticide applications for sugar esters are anticipated. Foreign patent applications are also in process.
AVA plans to have the Sucrose Octanoate Esters and follow-on sugar ester pesticides manufactured by Applied Power Concepts, Inc. (APC) in Anaheim, CA. APC has been AVA’s long-time technology development partner and has pioneered the development of patented “zero discharge” chemical manufacturing processes, including those used to manufacture AVA’s sugar ester pesticide products.
AVA does not plan to develop its own marketing/field development organization and is presently interviewing candidate collaborators for both the U.S. and foreign markets.

Contact:
AVA Chemical Ventures, L.L.C.
80 Rochester Ave., Suite 214
Portsmouth, NH 03801
Attn: Anthony Barrington
Managing MemberE-mail: avachem@gsinet.net
Phone: 603-431-4242
Fax: 603-430-8029

AVACHEM SUCROSE OCTANOATE [40.0%]
Biochemical Miticide For Varroa Mite Control on Honey Bees
ACTIVE INGREDIENT
Sucrose Octanoate Esters (a-D-Glucopyranosyl - ß-D-fructofuranosyl - octanoate),
mono-, di-, and triesters of sucrose octanoate 40.0%
OTHER INGREDIENT 60.0%
TOTAL 100.0%
EPA Reg. No. 70950-2 EPA Est. No. -___________________
U.S. Patent #’s 5,756,716; 6,419,941
STOP - READ THE LABEL BEFORE USE
KEEP OUT OF REACH OF CHILDREN
WARNING - AVISO
Si usted no entiende la etiqueta, busque a alguien para que se la explique a usted en detalle.
(If you do not understand the label, find someone to explain it to you in detail.) FIRST AID
If in eyes: • Hold eye open and rinse slowly and gently with water for 15-20 minutes.
• Remove contact lenses, if present, after the first 5 minutes, then continue rinsing eye.
• Call a poison control center or doctor for treatment advice.
If swallowed: • Call poison control center or doctor immediately for treatment advice.
• Have person sip a glass of water if able to swallow.
• Do not induce vomiting unless told to do so by the poison control center or doctor.
• Do not give anything by mouth to an unconscious person.
HOT LINE NUMBER: 888-229-7414
Have the product container or label with you when calling a poison control center or doctor, or going for treatment. You may also contact AVA Chemical Ventures, L.L.C. at 603-431-4242 for emergency medical treatment information.
Manufactured for:
AVA Chemical Ventures, L.L.C.
80 Rochester Avenue, Suite 214
Portsmouth, NH 03801

Net Contents: 1 Gallon, 5 Gallons

PRECAUTIONARY STATEMENTS
Hazard to Humans and Domestic Animals:
WARNING: Causes substantial but temporary eye injury. Do not get in eyes or on clothing. Wear protective eyewear (goggles or face shield). Wash thoroughly with soap and water after handling. Remove contaminated clothing and wash clothing before reuse.
Environmental Hazards:
Do not apply directly to water, or to areas where surface water is present or to intertidal areas below the mean high water mark. Do not contaminate water when cleaning equipment or disposing of equipment wash waters.

DIRECTIONS FOR USE
It is a violation of Federal Law to use this product in a manner inconsistent with its labeling. Do not apply this product in a way that will contact workers or other persons, either directly or through drift. Only protected handlers may be in the area during application. For any requirements specific to your State or Tribe, consult the agency responsible for pesticide regulation.

Do not allow spray to drift from the application site and contact people, structures people occupy at any time and the associated property, parks and recreational areas, non-target crops, aquatic and wetland areas, woodlands, pastures, rangelands or animals. Apply only when wind speed is not more than 10 mph. For sprays, apply largest size droplets possible.

GENERAL INFORMATION
AVACHEM SUCROSE OCTANOATE is a biochemical miticide for use against Varroa mites (Varroa destructor) on adult honey bees. It is primarily a contact miticide with limited residual activity.
® Do not apply this product through any type of feeding/watering system.
® Apply as soon as infestation is detected.
® Use in sufficient water to achieve adequate coverage of the adult honey bee population.
® Repeat applications at intervals of 7 - 10 days, up to three times per infestation, to control mites emerging from brood cells.
® Thorough spray coverage of adult honey bees on frames is essential for good control of the pest. Remove frames with adhering bees and spray both sides. MIXING AND APPLICATION
Shake or stir before use.
AVACHEM SUCROSE OCTANOATE dissolves readily in water. To achieve and to maintain the suspension, add the appropriate quantity to water with agitation and maintain gentle agitation during application.
Rate: Use a 0.625% v/v solution of this product.
Apply 1.5 fl. Oz. (45 ml) of total mix volume on each full depth frame of bees. [Typical 18 frame two story colony will receive 27 fl. Oz. (810 ml) of total mix volume.]

Rate Table
Total Mix
Volume % v/v
Solution
Amount
English
(Metric)
2 gal.
(7.57 liters) 0.625%
3 TBS
(50 ml.)
10 gal.
(37.85 liters) 0.625%
1 Cup
(235 ml.)

Timing of Application
Initiate applications as soon as Varroa mites are observed. Repeat applications at intervals of 7 - 10 days, up to three times per infestation, to control mites emerging from brood cells.
Test Application
This product has been tested on European-derived honey bees managed in standard Langstroth style beehives in temperate areas of North America. However, it is not possible to evaluate all management systems and climatic conditions. Test AVACHEM Sucrose Octanoate for possible detrimental effects on honey bees by treating a few beehives at the label use rate prior to large scale use.
Application
• This product may be applied with a garden type hand held or backpack sprayer. Do not apply this product through any type of feeding/ watering system.
• This product must come into contact with the Varroa mites to be effective. Complete wetting of the adult honey bee population on frames is essential for maximum control.
• Do not apply when honey bees are in winter cluster or at temperatures below 55°F to avoid chilling the bee population.

STORAGE AND DISPOSAL
Do not contaminate water, food, or feed by storage or disposal.
Pesticide Storage: Store in a cool, dry location.
Pesticide Disposal: Wastes resulting from the use of this product may be disposed of on site or at an approved waste disposal facility.
Container Disposal: Triple rinse (or equivalent). Then offer for recycling or reconditioning, or puncture and dispose of in a sanitary landfill, or by incineration, or, if allowed by state and local authorities, by burning. If burned, stay out of smoke.

WARRANTY STATEMENT, DISCLAIMER
AVA Chemical Ventures, L.L.C. (AVA Chemical) seeks to present reliable information concerning the composition, properties and use of the product, however: (1) All advice concerning selection and use of this product is provided at no charge and with no warranty. (2) No warranty is made hereby. The product described herein is warranted to conform to AVA Chemical specifications, therefore, only at the time of sale. THIS WARRANTY IS EXCLUSIVE AND IN LIEU OF ANY AND ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, ARISING BY LAW OR CUSTOM, INCLUDING BUT NOT BY WAY OF LIMITATION, THE IMPLIED WARRANTY OF MERCHANTABILITY AND THE IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE. Remedy for any breach of warranty is limited to replacement of the defective product. (3) AVA Chemical assumes no responsibility for any patent liability arising from the use of the product in a process, manner or formula not designed by AVA Chemical. Nothing in the listed information shall be construed as an inducement or recommendation to use any process or to produce or use the product in conflict with existing or future patents.