Personal safety of field workers is an important issue. We rarely forget the hazards to workers operating in politically sensitive areas, however dangers present in other situations (e.g. aquatic weeds in deep water, health hazards from land or water pollution, wildlife) are just as real. Failure to identify dangers may lead to tragic and also legal consequences.

The degree of site security and/or freedom from outside interference

It is almost impossible to guarantee the security of a release site, although some sites are obviously more risky than others. Loss of valuable release sites can result from various human activities including herbicide spraying, mechanical clearing and vandalism. Some of these problems may theoretically be avoided by consulting local governments, land-owners and local workers during formulation of plans or later during project operations.

The quality of plants at the site

In many cases, mass rearing of agents will have occurred on ideal plants grown under sheltered conditions, eg. glasshouses, and protected from the rigours of other herbivore species and environmental extremes. Sometimes it is possible to identify areas within a weed population where plants appear significantly healthier. Where this is likely to have resulted from better nutrition of the plant, the agents may have a greater chance of establishing.

How progress of the project is to be monitored

Within this framework, it is obviously best to be able to control, or at least influence, the decisions about which release sites should have highest priority status.

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