Regional consultation

Australia is the only country which is also a continent, and exotic species that we import are therefore unlikely to spread into other countries (except perhaps to Papua New Guinea). All other countries have to accept that biological agents do not respect political borders, and once established in one country will spread to neighbouring ones, until stopped by a change in climate or an ocean barrier. For example, the moth Cactoblastis cactorum, introduced into the Caribbean for the control of several pest cacti, has spread northward naturally or through deliberate introductions, and has now reached Florida in the mainland USA. Here it is damaging endangered species of cactus, and threatening the cactus areas of Mexico and the western USA (Pemberton 1995).

There may be conflicts of interest between different countries regarding release of agents. For example, Chromolaena is regarded as a serious weed in most African countries, but some scientists regard it as a useful plant in short-term fallow systems (Herren-Gemmill 1991). Agents established in one country will spread to the others, which may not be desired.

Consultation does not mean that nothing can be imported unless all countries are in agreement; countries remain sovereign and free to make their own decisions. It does however mean that other countries in the area should be informed and their wishes at least taken into account if there is a conflict.

Introductions in the public interest

Introductions should not be made when they favour only one sectional group and will cause harm to other groups in society. For example, a proposed introduction might control a plant which is a weed in plantation crops but is used as a food plant by peasant farmers. Or the agent might severely damage a native plant which is an important larval food for native butterflies. At present, not all countries consider all these aspects before granting permits to import insects.

Host testing and acceptance of testing done elsewhere

Many countries do not accept the results of host-testing done elsewhere and insist all tests are repeated in their country, which is very time-wasting. It is sensible to test plants of importance which have not been tested, and also native plants closely related to the host weed. It is also wise to test local cultivars of any crop plant closely related to the host weed, but otherwise there is no need to repeat tests already done in great detail in other countries. For example, Uroplata girardi and Octotoma championi for the biological control of lantana, and Procecidochares alani for the biological control of mistflower, were imported into Australia on the basis of host-testing conducted in Hawaii. The only additional testing required before the release of the agent was on a few native plants.

Use of pathogens

Most weed biological control programs use insects as biological control agents, and most of the scientists involved are entomologists. This may have resulted in a false belief that plant pathogens are not as safe. Many plant diseases are highly host-specific and make very effective biological control agents, and there is a need to consider them as well. Plant pathologists should therefore be included in the permit approval system as well as entomologists. At present, committees considering applications too often consist of entomologists and weed scientists only.

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