Pheromone-Trap Monitoring System for Pea Leaf Weevil, Sitona lineatus: Effects of Trap Type, Lure Type and Trap Placement within Fields

Abstract

The pea leaf weevil, Sitona lineatus, is an important pest of field peas and faba beans worldwide. Present sampling techniques that rely on detection of adult feeding damage are labor intensive, time consuming and require repeated sampling. Semiochemical-based pest monitoring systems could improve pea leaf weevil management. This study, which was conducted in the Golden Triangle region of Montana, tested several factors that potentially might affect capture rates of pheromone-baited traps, including trap and lure type and trap placement. Pheromone-baited pitfall and ramp traps caught significantly more adults than ground or delta traps, in all study areas. Pitfall traps baited with gray rubber septa captured significantly more adults than traps baited with membrane formulations or controls in both pea and lentil fields. In addition, pheromone-baited pitfall traps positioned in the southern part of pea fields captured relatively higher numbers of adults than those placed in northern parts of fields, although this difference was not significant. These findings can be used to improve adult weevil monitoring and should be taken into consideration when developing an integrated pest management program.

Keywords: crop; insect; lure; pheromone; pitfall trap; trap.

Figure 1

Montana State showing field sites: (1) trap type and placement and (2) lure type. Green and pink circles indicate field pea and lentil fields, respectively.

Figure 2

Trap types (pitfall, delta, ground and ramp traps) used to evaluate the most effective trap design in capturing the pea leaf weevil, Sitona lineatus.

Figure 3

Sitona lineatus adults captured by pitfall traps baited with pheromone at six experimental sites in the Golden Triangle, Montana.

Figure 4

Mean total captures per trap ± S.E. of Sitona lineatus adults in different traps in pea fields at southern, central and northern clusters of the Golden Triangle, Montana, from the first week of April to the end of July 2016. Mean values within bars bearing the same upper-case or lower-case letters in each cluster are not significantly different (Mann–Whitney U-tests followed by Bonferroni correction [α = 0.01]).

Figure 5

Mean total captures per pitfall trap ± S.E. of Sitona lineatus adults in pea and lentil fields at southern, central and northern clusters of the Golden Triangle, Montana, from the first week of April to the end of July, 2016. Mean values within bars bearing the same upper-case or lower-case letters in each cluster are not significantly different (Mann–Whitney U-tests followed by Bonferroni correction [α = 0.01]).