Sustainable management of the cereal leaf beetle, Oulema melanopus (Coleoptera: Chrysomelidae), a new invasive insect pest of cereal crops in western Canada

• Author / Creator

  Kher, Swaroop V

• The cereal leaf beetle, Oulema melanopus (L.) (Coleoptera: Chrysomelidae) is a new invasive insect pest of cereals in western Canada, and has expanded its geographic range significantly throughout the region. Its establishment has economic implications for grain production, trade and export. Biological control with its principal larval parasitoid, Tetrastichus julis (Walker) (Hymenoptera: Eulophidae), introduced from Europe has been the most successful management strategy in North America. In southern Alberta, the parasitoid has established naturally along with the beetle and provides an opportunity for integration of biological control with other management tactics. My investigation focused on tritrophic interactions between the cereal host plants, O. melanopus and T. julis. I investigated life histories and host preferences of O. melanopus and T. julis, their spatio-temporal distribution dynamics, and explored host-plant resistance mechanisms in exotic wheat genotypes to discern interrelations between these species.
  My studies on developmental patterns of O. melanopus on potential cereal hosts in western Canada (oat, wheat, barley, corn, rye and triticale) indicated that the preferences for these hosts and their utilization differed within the fundamental host range of O. melanopus. Prolonged developmental times and low survivorship on a local cultivar of oat, Waldern, indicated a potential avenue for designing strategies such as trap cropping. My studies on the biology of T. julis indicated that T. julis females prefer advanced larval instars for parasitization; such a selection lead to higher clutch size, and improved fitness. Under field
  conditions, the relationship of O. melanopus and T. julis indicated a tightly coupled host-natural enemy system. Tetrastichus julis exhibited strong density dependence. Host plant characteristics influenced field dynamics of O. melanopus which in turn influenced T. julis distribution.
  Three of the six central Asian wheat genotypes tested (NN-100, NN-78 and NN-27) were less attractive for O. melanopus oviposition and feeding and further trials on biology and fitness of the beetle suggested prolonged development and low fitness on these genotypes. This indicated presence of both antixenosis and antibiosis mechanisms. The resistant lines identified can act as effective genotypes for breeding explorations in North America.

• Subjects / Keywords

  • Sustainable management
  • Antibiosis
  • Cereal leaf beetle
  • Biology
  • Antixenosis

• Graduation date

  Spring 2014

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R31Z4207J

• 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.