Biological Control and the Reproductive Mode of Weeds

Abstract

(1) The genetic structure of agricultural plant populations has long been recognized as an important factor in their vulnerability or resistance to disease and pest attack. However, in the biological control of weedy plants, the potential significance of the population genetic structure of the target species appears to have been severely underestimated. (2) An examination of the degree of control achieved in eighty-one different control attempts demonstrated a significant correlation between the degree of control achieved and the predominant mode of reproduction of the target plant; asexually reproducing species were effectively controlled significantly more often than sexually reproducing ones. (3) It is argued from this result that the genetic structure of the target species has important implications with respect to the selection of species to be controlled using biological agents.