Volume 79, numéro 4, 1998
OECD Workshop - Sustainable Pest Management, Safe Utilization of New Organisms in Biological Control. Montréal, Québec, Canada. September 27-30, 1998.
Atelier de l’OCDE - Gestion durable des ennemis des cultures, Utilisation sécuritaire de nouveaux organismes de lutte biologique. Montréal, Québec, Canada. 27-30 Septembre 1998.
In Canada, microbial pest control products and agents are regulated under the Pest Control Products Act, administered by the Pest Management Regulatory Agency (PMRA) for the Minister of Health. A microbial includes bacteria, algae, fungi, protozoa, viruses, mycoplasmae or rickettsiae and related organisms. Microbial pest control products and agents can include those derived through genetic engineering. When the PMRA was established in 1995, specific directions were given by government to facilitate access to alternatives to traditional chemical products; to support environmental sustainability; and to pursue international cooperation to accelerate registration. Currently in Canada, there are 8 active ingredients and 34 products registered. In 1998, there were 19 research permits and notifications for active ingredients, an increase from 1997. Data requirements are set out in guidelines (Pro98-01 Regulatory Proposal: Guidelines for the registration of microbial pest control agents and products), rather than in regulation. General categories for data requirements for Tier 1 ( the set of information which is typically sufficient to allow regulators to determine that a product presents an acceptably low level of risk) include information or data on characterization, health toxicity, environmental toxicity, and efficacy. Pre-submission consultations between registrants and PMRA are encouraged. The main objectives of these consultations are to determine the appropriate study protocols and the subset of data requirements from the guidelines that may be required for the registration of a particular proposed product as well as the type of information required to support data waivers.
Key issues, questions and challenges regarding registration
1. Characterization of the microbial active ingredient is seen as critical and fundamental to the determination of the other data requirements both in environment and in health. The key components are:
• identification of the microorganism
• relationship to mammalian or other pathogens
• toxin producing potential
• manufacturing process, including potential for contaminants
• physical/technical properties, including storage stability.
2. Building on good information on characterization, for environmental risk assessment, information on host/target range, geographical distribution of host/target, and the geographical distribution of the microbial are key questions.
4. With respect to publicly-funded research groups, there is a need for links with commercial partners at an appropriate stage in order to love their products into the regulatory System and onto the marketplace. PMRA is working to support the registration and use of microbial products through developing data requirements appropriate to microbiais, working with growers and other stakeholders to support the implementation of Integrated Pest Management (IPM) strategies that include the use of microbials, harmonizing data requirements with both the US and other OECD countries, and ensuring the development of regulations and policies to encourage registration of these products.
In Denmark several factors like the national pesticide action plan, ethical questions, national research strategy, increasing share of organic farming and fees are affecting the policy regarding regulatory agencies approach for products supporting sustainable pest management.
The use of microbial pesticides in Denmark are limited, with the relatively largest share used in the greenhouse sector.
Approval of a product not sold in Denmark before July 26, 1993 consists of two parts: An EU approval of the active micro-organism, and a national approval of the product containing the active micro-organism. An EU approval of an active micro-organism is only granted if the active micro-organism is included in Annex I of the directive of authorized active organisms. As a main principle, an active micro-organism shall be entered on the list of authorized active organisms before the Danish EPA may grant an approval for sale or import of products containing active micro-organisms. Until now five new organisms have been recommended for EU approval and inclusion in Annex I of the Directive, but so far none have been included.
For products sold in Denmark before July 26, 1993 a transitional scheme specified in the Order is applied. Under this procedure application for approval of such products should be submitted to the Danish EPA before July 26, 1994 if the products were intended for sale in Denmark after this date. The application is considered at a national level only by the Danish EPA. The Danish EPA has received applications concerning nine different active micro-organisms.
Both GMO's and biocides are covered by specifie legislation. If the GMO's are also pesticides, they must also comply with the Danish pesticides legislation. As no transgenic microbial pesticides or microbial biocides have yet been registered in Denmark, there is no legal practice on this issue.
The National Registration Authority for Agricultural and Veterinary Chemicals (NRA) is the regulatory body responsible for the coordinated registration, regulation and review of agricultural and veterinary (agvet) chemicals up to and including the point of retail sale. This role is defined by the Agvet Code, 1994. Each of Australia's eight states and territories retains its own jurisdictional controls over the use of agricultural and veterinary products.
The NRA may issue permits to exercise control over research agricultural and veterinary (agvet) chemicals. Under defined emergency conditions, the NRA can also issue "emergency use" permits, and can approve the use of agvet chemicals for minor uses that do not normally appear on product labels, and would otherwise be illegal.
The Existing Chemicals Review Program of the NRA reviews registered agvet chemical products to ensure that they meet contemporary standards for efficacy, safety and health, and pose no undue risk to the environment or trade. Recently reviewed chemicals include atrazine, metham sodium, endosulfan and ethylene dibromide, and certain changes to their registration and labelling are being implemented. Several other chemicals are currently under review. The Special Review Program allows the NRA to review registered agvet products if there are any special issues arising that may alter the terms of their original registration.
Current challenges to the NRA include the management of insecticide and weed resistance, particularly in relation to the regulation of genes expressing insecticides and herbicide tolerance.
Specific guidelines for the registration of microbiological products are currently being reviewed. Issues relating to the release of microbial organisms into existing agricultural Systems and environments require considered risk assessment prior to any approval. Macrobiological control agents are specifically excluded from regulation by the NRA. They may, however, be regulated under other pieces of legislation.
Naturally occurring entomopathogenic bacteria provide an important resource for pest control. Greatest benefit will be obtained from the application of replicating bacteria which can establish in the host's environment and provide long term control. Bacteria developed for pest control are required to be safety tested and registered, yet bacteria are frequently introduced into the environment to enhance plant growth or aid soil processes without regulation. Why then, is the use of insect pathogenic bacteria treated differently? Augmentation of bacteria already present in the environment is unlikely to have any unwanted side effects as application is only changing the spatial and temporal distribution of the microbe and will have little long term effect on the total population. Users of the bacteria, however, will be exposed to the bacterium at a level higher than experienced naturally and potential adverse effects of this interaction should be addressed through Tier 1 safety testing. Non-target organisms should also be tested. If new organisms (exotic strains or modified bacteria) are to be introduced to the environment, their potential effects on the environment should be considered. The question of horizontal gene flow from applied bacteria also needs to be addressed. A better understanding of microbial ecology and Systems for tracking new strains and genes are essential to develop appropriate assessment procedures to ensure the safe utilisation of bacteria in biological control.
The registration procedures for microbial pesticides have been based by and large on those developed for registration of chemical pesticides. However, fungi as living organisms differ in many aspects from inert substances. These differences are pointed out and discussed in the light of practical experiences. A pragmatic registration procedure is proposed taking into account the use of a fungus based product in relation to its natural distribution and behaviour. On the one hand, the use of a fungus naturally occurring on the target host does not need a sophisticated registration procedure. On the other hand, however, a genetically altered fungus applied against a non natural host in a non natural habitat needs very careful examination.
Virus diseases of sweet potato are very prevalent and often seriously damage to the plants. Especially sweet potato feathery mottle virus severe strain (SPFMV-S) causes russet crack disease in Japan. In order to confer virus resistance against SPFMV using current biotechnology, we have produced transgenic sweet potato with an expression vector plasmid harboring the coat protein (CP) gene as well as hygromycin phosphotransferase gene (HPT). The plasmid was introduced into mesophyll protoplasts of a sweet potato breeding line, Chikei 682-11 (Ipomoea batatas L.(Lam.)) by electroporation. Protoplatsts were further cultured in the presence of hygromycin. Some of the hygromycin resistant calli were grown to form adventitious shoots. Southern blot analysis with CP and HPT genes showed that these genes were integrated into the chromosomes in four lines. Expression of the CP gene was confirmed by Northern and dot immuno blot analyses. Each line was grafted with the SPFMV-S infected morning glory (I. nill) to reveal any virus resistance conferred. After three months from the graft-inoculation, these transgenic plants were used for ELISA test in order to know any virus infection. There was no significant differences of ELISA values between the inoculated-transgenic and the non inoculated-virus free plants, suggesting that these transgenic plants were not infected with the virus. They produced storage roots, from which the young shoots were again found to be virus-free by ELISA. We concluded that these transgenic plants were highly resistant to the virus. Concerns about the releasing transgenic plants that contain genes from other species include the potential weediness of the plants as well as the potential flow of the transgenic genes to other plants through normal outcrossing. Usually sweet potato is a vegetatively propagated and hardly flowers during growing seasons in Japan. Under these circumstances it might be safe to release these transgenic plants. One concern unique to virus resistant transgenic plants is that a viral sequence from transgene may be potentially incorporated by RNA recombination into a virus that may infect the transgenic plants. There is no useful information available on the occurrence of recombinant virus under the very high level of resistance. From the point; whether or not the frequency of recombination in the transgenic plants greater than that in plants with two or more viruses, it would be at least much lower in these highly virus resistant transgenic plants.