Pest Management Strategy - Elimination of American Foulbrood Without the Use of Drugs
A Practical Manual for Beekeepers, by Mark Goodwin and Cliff Van Eaton

1 Introduction

1.1 Significance of American Foulbrood to New Zealand

American foulbrood (AFB) is the most serious honey bee disease in New Zealand, the control of which is a major cost to New Zealand beekeepers. In 1996, the combined cost of the disease (including beehive inspection, destruction of diseased beehives and loss of production) was estimated at NZ$2.9 million, or roughly 6% of the annual gross returns of the New Zealand beekeeping industry.¹

Unlike most other countries, New Zealand beekeepers do not use antibiotics to control the disease (the use of drugs to control AFB is illegal under New Zealand law). Control is through managing honey bee colonies to reduce the spread of disease and the destruction of colonies that are found to have AFB.

1.2 The American Foulbrood Pest Management Strategy

New Zealand has had legislation to control AFB since 1906. The most recent change in that legislation occurred in 1998, when the Biosecurity (National American Foulbrood Pest Management Strategy) Order was passed into the law. The Order established an American Foulbrood Pest Management Strategy (AFB PMS) under the Biosecurity Act.

The Biosecurity Act allows New Zealand agricultural industries affected by a pest or disease to determine their own goals and strategy for its control, and to use legal powers to ensure the strategy is carried out. In the case of AFB, the National Beekeepers' Association (NBA), the representative organisation of the beekeeping industry, developed the AFB PMS, and went through the process of having the strategy approved by government.

The Management Agency for the AFB PMS is the NBA. The NBA has the statutory responsibility to implement the AFB PMS, which comprises a range of regulatory and educational programmes (including this manual). The NBA also funds the strategy, using income generated from a mandatory levy on apiaries.

1.2.1 Goal of the AFB PMS

The goal of the AFB PMS is to eliminate American foulbrood in managed colonies (ie, beehives) in New Zealand. The beekeeping industry is breaking new ground in setting this goal. Elimination of AFB has not been achieved on a national scale before, although there are examples of other animal diseases being eradicated from a country (brucellosis in New Zealand is one good example).

Elimination of AFB is seen as possible in New Zealand both because the country has a relatively small population of honey bee colonies (estimated to be 350,000 to 400,000 including feral colonies), and because importations of additional colonies and other materials capable of carrying AFB are strictly controlled.

Some New Zealand beekeepers have also shown that elimination on a national level is possible. By destroying colonies with AFB instead of using antibiotics, and using management techniques to avoid the spread of the disease to other hives, they have effectively eliminated the disease from their own outfits.

Finally, the chances of AFB elimination are enhanced by the current low incidence of the disease in New Zealand, and its relatively low infectivity.

1.2.1.1 Feral Colonies

Honey bees exist as feral colonies in many parts of New Zealand. However, the presence of feral colonies is not seen as an impediment to eliminating AFB. Feral colonies can develop AFB infections, but are not a major source of infection for managed colonies. This is because feral colonies are generally short-lived and usually only become infected with AFB when their foragers rob honey from infected colonies. Beekeepers who have eliminated AFB from their own beehives are usually not subject to re-infections from local feral colonies.

As the incidence of AFB in managed hives decreases, so too will the incidence in feral colonies, since research has shown that in New Zealand in most circumstances feral colonies are at a greater risk of becoming infected with the disease from managed hives, than are managed hives from ferals.²

Nevertheless, under certain circumstances feral colonies may be an important source of infection, either because of local conditions, or because the population of beehives in the area is free of the disease. This manual therefore includes information on testing feral colonies for AFB, and destroying infected feral colonies.

1.3 Objectives of the AFB PMS

The primary objective during the first (4 year) term of the AFB PMS is to reduce the incidence of AFB in managed colonies by an average of 10% each year. The primary objective in the second (5 year) term is to reduce the reported incidence of the disease to below 0.1% by the end of the term.

While the 10% per year reduction would appear at first glance to be a difficult objective to achieve, the NBA's previous AFB Control Programme (1991-98) met or exceeded that percentage reduction figure in all but one reporting period.

The AFB PMS seeks to achieve its primary objective by using the following means:

A set of legal responsibilities on the part of all beekeepers, which are a continuation of the previous Apiaries Act. These responsibilities include:
- registration of all apiaries
- reporting of cases of AFB to the Management Agency (both when found and on an annual basis)
- destruction of all cases of AFB
Disease Elimination Conformity Agreements (DECAs), a document that provides beekeepers with a means to commit to a personal plan to eliminate AFB from their beehives, and to make changes to the plan if disease levels do not decrease
Certificates of Inspection (C of Is) to ensure that all beehives belonging to beekeepers without a DECA also receive an adequate level of inspection for AFB
A course on AFB recognition and destruction, and a competency test, to ensure that all beekeepers carrying out inspections have a demonstrated ability to diagnose AFB
Audits of DECAs and C of Is, using both physical inspections and spore tests, to ensure compliance with the provisions of the strategy, and to detect any new outbreaks of the disease
Counselling of beekeepers with AFB problems
On-going educational programmes in AFB recognition and destruction, using the network of NBA branches throughout New Zealand

1.4 Aim of This Manual

The aim of this manual is to provide beekeepers with:

background information on American foulbrood disease

practical methods they can use to eliminate the disease from their beekeeping outfits

The manual is designed to be useful to all beekeepers, whether they own one beehive, or manage a large-scale commercial beekeeping enterprise. It includes case studies, and describes management techniques New Zealand beekeepers have used to overcome large-scale AFB outbreaks and eliminate disease infections in their hives.

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