Dispersal of Liriomyza trifolii

The agromyzid fly Liriomyza trifolii , which has generally been considered as a secondary pest, could turn into a major international pest. Up to the seventies this leafminer occurred only in Caribbean countries, and southern and eastern USA. It then became resistant to several insecticides in Florida. Extensive transport of plant material between production areas has resulted in the establishment of this insect in many countries, despite chemical treatment before and after transport and quarantine procedures. The human-mediated dispersal of L. trifolii is described, phytosanitary and quarantine measures are reviewed and finally plant protection policy is discussed.