Host Range Testing of a Previously
Tested Agent for Release into a New Country
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Cactoblastis cactorum, which not be appropriate
for introduction
into a country where cacti are important.
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The host range of a monophagous insect is independent of environment. It will remain monophagous in any environment. Therefore, once it has been conclusively proven that an insect is monophagous it is not necessary to test it again. For example, the salvinia weevil
Cyrtobagous salviniae is known, from laboratory and field studies, to attack only
Salvinia molesta and other closely related sympatric Salvinia
species. Other Salvinia species occurring elsewhere are not host plants. This insect is suitable for release in any country without further testing. If an insect is
oligophagous, it may be suitable for release in one environment but not another. For example,
Cactoblastis cactorum attacks several species of
Cactaceae. It is suitable for release in Australia where there are no native Cactaceae nor any beneficial introduced species. However, it may not be appropriate to introduce this insect into a country where Cactaceae are ecologically or environmentally important, without careful assessment of the risk. |
