Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 4 of 4

Full-Text Articles in Life Sciences

Exotic Weed Invasion Increases The Susceptibility Of Native Plants To Attack By A Biocontrol Herbivore, Tatyana A. Rand, Svata M. Louda Jun 2004

Exotic Weed Invasion Increases The Susceptibility Of Native Plants To Attack By A Biocontrol Herbivore, Tatyana A. Rand, Svata M. Louda

Faculty Publications in the Biological Sciences

Landscape change has great, yet infrequently measured, potential to influence the susceptibility of natural systems to invasive species impacts. We quantified attack by an invasive biological control weevil (Rhinocyllus conicus) on native thistles in relation to two types of landscape change: agricultural intensification and invasion by an exotic thistle, Carduus nutans, the original target of biological control. Weevil egg load was measured on native thistles in three landscape types: (1) agriculture dominated, (2) grassland dominated with exotic thistles, and, (3) grassland dominated without exotic thistles. We found no difference in egg load on native thistles within grassland landscapes without exotic ...


Local- Vs. Landscape-Scale Indirect Effects Of An Invasive Weed On Native Plants, Tatyana A. Rand, F. Leland Russell, Svata M. Louda Jan 2004

Local- Vs. Landscape-Scale Indirect Effects Of An Invasive Weed On Native Plants, Tatyana A. Rand, F. Leland Russell, Svata M. Louda

Svata M. Louda Publications

Insect-mediated indirect interactions between native plant species recently have been shown to be important determinants of plant performance in a number of ecological communities. However, the potential indirect effects of exotic plant invasion on native plant species are not well understood. We examined whether the presence or proximity of the targeted exotic weed, musk thistle, influences the magnitude of attack on native thistles by the introduced biological control, flowerhead weevil. At the local scale, we quantified weevil egg densities on heads of the native wavyleaf thistle growing at different distances (0 to 100 m) from patches of the exotic thistle ...


Impact Of Ceutorhynchus Litura Feeding On Root Carbohydrate Levels In Canada Thistle (Cirsium Arvense), Gary L. Hein, Robert G. Wilson Jan 2004

Impact Of Ceutorhynchus Litura Feeding On Root Carbohydrate Levels In Canada Thistle (Cirsium Arvense), Gary L. Hein, Robert G. Wilson

Faculty Publications: Department of Entomology

Canada thistle is a serious perennial weed found throughout the northern regions of the United States and Canada. The weevil, Ceutorhynchus litura (F.), was first released in Canada in 1965 as a potential biological control agent for Canada thistle; however, its impact as a control agent has been sporadic. The objective of this study was to characterize C. litura impacts on the carbohydrate profile in Canada thistle roots through the growing season and to evaluate the potential for this biological control agent in causing stress to Canada thistle. Field plots, infested with C. litura, were established and extensively sampled for ...


Habitat Manipulation Of The Apple Orchard Floor To Increase Ground-Dwelling Predators And Predation Of Cydia Pomonella (L.) (Lepidoptera: Tortricidae), Clarissa R. Mathews, Dale G. Bottrell, M. W. Brown Jan 2004

Habitat Manipulation Of The Apple Orchard Floor To Increase Ground-Dwelling Predators And Predation Of Cydia Pomonella (L.) (Lepidoptera: Tortricidae), Clarissa R. Mathews, Dale G. Bottrell, M. W. Brown

Publications from USDA-ARS / UNL Faculty

Augmenting generalist predator populations in new apple (Malus domestica Bork) plantings could potentially aid in the establishment of balanced orchard ecosystems that are less susceptible to pest outbreaks. Habitat can be an important factor in retaining predators in a system and can affect predator efficiency. We investigated the potential of increasing a complex of generalist ground-dwelling predators and enhancing biological control in a young 'Golden Delicious' apple orchard through ground habitat manipulation. We modified the orchard floor with four comparative habitat treatments: (1) detritus-rich compost mulch layer, (2) detritus-free synthetic mulch layer, (3) herbicide-treated vegetation thatch, and (4) bare soil ...