Potential for suppressing Diprion similis(Hymenoptera: Diprionidae) with pheromone trapping: a population model.
In connection with the possible use of pheromone trapping for the control of Diprion similis(Htg.) on pines in the United States, a mathematical model based on one of several described by E.F. Knipling & J.U. McGuire, Jr. [cf. RAE/A 56, 1359] was developed, to assess the feasibility of population suppression with traps baited with the sex pheromone produced by virgin females. Departure from existing models resulted chiefly from the arrhenotokous nature of the sawfly. The model predicts alternating generations which undergo first a large shift in the sex ratio but no population reduction, followed by a large decrease in population size with a moderating sex ratio. Four generations of intensive trapping would theoretically be sufficient to eliminate the sawfly from an isolated area.