Thesis
Describing the natural history and control of two defoliators (Orthosia hibisci Guen e and Gluphisia septentrionis Walker) in Pacific Northwest hybrid poplars
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/100786
Abstract
Two important lepidopteran defoliators, Orthosia hibisci Guenée and Gluphisia septentrionis Walker, attack hybrid poplars in the Pacific Northwest. These pests cause severe defoliation; and hundreds of hectares have been sprayed with either indoxacarb or diflubenzuron to control them the past three years. The lack of information about their natural history in the region has limited the implementation of an integrated pest management program for these defoliators. Male O. hibisci (Lepidoptera: Noctuidae) moths were monitored using sex pheromone (Z9-14:Z11-14 aldehyde) baited traps. Trap captures indicated O. hibisci flies from February to June. Experiments with this sex pheromone showed that trap design played an important role in capturing male moths. It was also observed that a mating disruption technique for this pest did not provide promising results to influence O. hibisci population in the targeted areas. The second pest, G. septentrionis (Lepidoptera: Notodontidae), is the most damaging lepidopteran defoliator in the poplar system. Light trapping indicated that it flies from April to September, with a peak in June and another in August. Laboratory rearing indicated that the summer Gluphisia life cycle takes approximately 36 to 47 days. It was also determined that the last instar larva is the most damaging stage and consumes approximately 95% of a poplar leaf in a day. For the first time, Gluphisia was successfully monitored using sex pheromone (Z11, E13-16 aldehyde) baited traps. Gluphisia male moth captures were significantly increased when traps were baited with 5 mg of the sex pheromone. Field observations indicated that there was an active beneficial insect fauna diminishing both Orthosia and Gluphisia populations. These biological control agents are: Trichogramma sp. (Hymenoptera: Trichogrammatidae), Eulophus orgyiae Fitch (Hymenoptera: Eulophidae), a predator bug (Hemiptera: Pentatomidae), and a parasitic fly (Diptera: Tachinidae). Orthosia and Gluphisia still represent a major threat for poplar production in the Pacific Northwest. Research on their natural history has provided valuable information to predict when the most damaging stages will be present in the system. Pheromone work also showed that trap design, pheromone delivery system and pheromone load influenced male moth captures. Further research on beneficial insects in the system is needed.
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Details
- Title
- Describing the natural history and control of two defoliators (Orthosia hibisci Guen e and Gluphisia septentrionis Walker) in Pacific Northwest hybrid poplars
- Creators
- Alejandro Ivan Del Pozo-Valdivia
- Contributors
- John J. Brown (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525164401842
- Language
- English
- Resource Type
- Thesis