Suitability Ofanaitis Plagiata(geometridae) for Biocontrol Ofhypericum Perforatumin Dry Grassland of British Columbia

The suitability of a European mothAnaitis plagiata(L.) for the biological control of the weedHypericum perforatumL. in British Columbia is evaluated. It is concluded that the introduction of the moth is justified as it offers prospects of reducing the weed density without damage to economic plants.A.plagiatais preadapted to dry habitats and ecologically restricted to them. Its high fecundity and two generations a year should enable it to reach an effective population level rapidly and the early spring feeding by the overwintered larvae should damage the weed when it is most vulnerable. It was shown by feeding tests that the larvae are restricted to plants in the genusHypericum. Furthermore, all the known hosts of the genusAnaitisare restricted to the genusHypericumwhich indicates that the insect-host plant relationship is an old and highly stable one. Larval feeding was found to be partly in response to a chemical compound present in the cuticular waxes of the host plant.