Optimization of semiochemical monitoring for pea leaf weevil, Sitona lineatus (Coleoptera: Curculionidae), in the Prairie Provinces

  • Author / Creator
    St.Onge, Amanda J
  • The pea leaf weevil, Sitona lineatus Linnaeus (Coleoptera: Curculionidae) is an invasive pest of increasing concern to pulse producers in the Canadian Prairie Provinces. Pea leaf weevil larvae cause damage to field pea (Pisum sativum) and faba bean (Vicia faba) crops by feeding on root nodules which contain nitrogen-fixing Rhizobium bacteria. Larval feeding reduces the nitrogen balance of the pea and bean crops, causing a reduction in the number and quality of pods, as well as reducing the amount of fixed nitrogen available in the soil for future crops. Larval feeding is difficult to monitor but adult weevils are active aboveground, particularly during spring and fall dispersal to reproductive or overwintering sites, respectively. Both sexes of adults are attracted to semiochemicals, including the male-produced aggregation pheromone (4-methyl-3,5-heptanedione) and host plant volatiles ((Z)-3-hexenol, (Z)-3-hexenyl acetate, and linalool). The purpose of this research is to develop an optimal semiochemical trap, which reliably attracts and retains PLW, is related to PLW activity in fields, is cost effective, and can be used for monitoring pea leaf weevil in field pea crops in the Canadian Prairie Provinces. Different combinations of semiochemicals at various release rates were tested in pitfall traps positioned at the edge of pea crops in southern Alberta. Weevils were attracted to aggregation pheromone lures in both the spring and fall activity periods; the addition of host plant volatiles to the pheromone lure sometimes enhanced weevil captures, especially in the fall. Of the various trap types tested to capture and retain weevils including various cone traps, sticky traps, unitraps, and pitfall traps, the pitfall traps were the most successful. A secondary objective of this research was to investigate seasonal plasticity in pea leaf weevil response to semiochemicals. Male and female pea leaf weevil adults were tested individually in a 4-way olfactometer for their response to four natural odour sources: 1) five male pea leaf weevils; 2) five male pea leaf weevils on pea plants; 3) pea plants; or 4) a blank control. Weevils in three physiological states were tested in the olfactometer: newly eclosed, recently overwintered, and reproductively active. The response of pea leaf weevils in the olfactometer bioassays did not differ with weevil physiological state or sex. Weevils of all physiological states and both sexes responded preferentially to odours released by male pea leaf weevils. The semiochemical traps developed here can be used to determine the presence of pea leaf weevil in its expanded range. These semiochemical traps are also useful to monitor the arrival of pea leaf weevil into a pea crop at the start of the season, to better time the application of foliar insecticides. Further research relating captures of PLW in the fall to weevil damage in the upcoming spring would provide pea producers with a method to predict upcoming damage.

  • Subjects / Keywords
  • Graduation date
    2017-11:Fall 2017
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Department of Biological Sciences
  • Specialization
    • Ecology
  • Supervisor / co-supervisor and their department(s)
    • Evenden, Maya (Biological Sciences)
    • Cárcamo, Hector (Agriculture and Agrifood Canada)
  • Examining committee members and their departments
    • Erbilgin, Nadir (Agricultural, Life & Environmental Sciences)
    • Keddie, Andrew (Biological Sciences)