Assessing trap and lure effectiveness for the monitoring of Sirex noctilio

Abstract

1. Lure-baited traps are an important tool for monitoring the spread and establishment of the Sirex woodwasp Sirex noctilio. The utility of these traps, however, is limited in areas with low wasp populations due to the reliance on a plant volatile (kairomone) lure in the absence of an identified pheromone. Knowledge of the optimal trap type and deployment strategy is also lacking. 2. We tested the effectiveness of a putative pheromone in baited traps, by means of a series of field trials in South Africa over a three-year period. We also examined the influence of lure type, trap type and trap height on capture success. 3. The pheromone was found to be ineffective as an attractant under South African field conditions for both male and female wasps. Lure type, trap type and trap height were found to have little to no effect on female wasp catch. Given moderately strong responses to the blend in wind tunnel and laboratory conditions, we suggest possible aspects of the biology and life history of S. noctilio that may influence lure effectiveness. 4. The traditional black intercept panel traps with kairomone lure remains the best trap for S. noctilio, at least where populations are high.