Classic biological control can be a powerful option for those tasked with managing biological invasions; however, some biocontrol releases lead to non-target attack – feeding, damage or development on species other than the target species. The cinnabar moth, Tyria jacobaeae L. (Lepidoptera: Erebidae) was introduced to Western Oregon as a...
Non-target effects are one of the greatest potential risks of weed biological control programs, and understanding non-target effects of biological control at the population level is crucial for predicting when they will occur and altering the perception of biological control as a whole. In this thesis, we assessed the ecological...
While current theories describing the insect-plant interaction
have emphasized the biochemical aspects of the relationship,
morphological components can also play a significant role in
determining which plants or tissues are susceptible to insect attack.
Xylem sap on which spittlebugs feed may lack many of the plant
compounds responsible for host...
Hand-defoliation was evaluated for its ability to
simulate herbivory by cinnabar moth larvae, Tyria
jacobaeae (L.) (Arctiidae) on the weed tansy ragwort,
Senecio jacobaea L. (Asteraceae). The evaluation was done
on a field population of flowering ragwort, for three
different timings (early, middle, and late season) of
damage.
In the...
I conducted field and laboratory studies to determine the impact of the cinnabar moth, Tvria jacobaeae L., on the native perennial herb, Senecio triangularis Hook. The cinnabar moth was introduced into Oregon in 1960 to control the noxious weed Senecio jacobaea L. and is now well established on both the...
Field experiments were done to test the relative
effectiveness of single and multiple biological control
agents in reducing weed populations using two insects, the
cinnabar moth, Tvria iacobaeae (L.), and the ragwort flea
beetle, Lonqitarsus iacobaeae (Waterhouse). These two
insects were released for biological control of the biennial weed tansy...
I used field experiments to study how plants in two grassland communities colonized
soil mounds made by the Camas pocket gopher, Thomomys bulbivorus (Richardson). I
identified potential mound colonizers in each source of colonization (buried propagule bank,
seed rain, and established vegetation) and then measured species specific rates of
colonization...
I conducted field studies to determine the effect of insect herbivory and
intraspecific plant competition on ragwort Senecio jacobaea. The objectives were to
determine the patterns and causes in the distribution of the ragwort flea beetle
Longitarsus jacobaeae foraging among varying densities of ragwort, to measure the
behavioral and numerical...
In the first part of this study we monitored the development of biological control
of purple loosestrife Lythrum salicaria over a six-year period at Morgan Lake in western
Oregon. In 1992, two beetles, Galerucella pusilla and G. calmariensis (Coleoptera:
Chrysomelidae), were released to control the wetland weed at this test...
The cinnabar moth, Tyria jacobaeae (L.) (Lepidoptera:Arctiidae), was released in 1959 to control the grassland weed tansy ragwort, Senecio jacobaea L. (Asteraceae), despite evidence that caterpillars of this species can feed on native plants within the genera Senecio and Packera. Previous studies confirmed the moth's ability to develop on the...