Thesis (M.S.)--University of Kentucky, 2000. / Title from document title page. Document formatted into pages; contains viii, 52 p. : ill. Includes abstract. Includes bibliographical references (p. 47-51).

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

No description available.

Cropping systems were: corn + atrazine + EPTC/dichlormid; corn + atrazine + metolachlor; corn + atrazine + bentazon; corn + EPTC/dichlormid intercropped with red clover as green manure or managed as forage crop in the following year; alfalfa + EPTC; soybean + metalachlor + metribuzin; sorghum as green manure followed by winter wheat; and spring barley + diclofop-methyl + bromoxynil. Control treatments were yellow nutsedge growing in a pure stand and complete yellow nutsedge control. After two growing seasons in experiment #1, the tuber population had decreased in all cropping systems. Yellow nutsedge was reduced to 9% of the initial population under perfect control while it tripled in the pure stand. After the first growing season in the second experiment, only corn intercropped with red clover significantly reduced yellow nutsedge population by 17%. When the systems were not treated with herbicides, the yellow nutsedge population increased between 41 to 180% in all cropping systems. There was a significant relation between yellow nutsedge, broadleaf weed and grass densities and yellow nutsedge tuber production. Corn was the most profitable cropping system. The least economically advantageous cropping system was barley.

No description available.

The success of biological weed control programs has been limited by a lack of understanding of the stress physiology of insect damage and pathogen development. This case study with the perennial weed, Cirsium arvense, (L.) Scop. evaluated the stress of five natural enemies. Attack by a seed head predator, Orellia ruficauda (F.) caused about 21.5% predation and may reduce seed dispersal. The stress of stem gall formation (Urophora cardui (L.)) is greatest when the gall occurs on young plants and on the mainshoot and defoliation simulation (Cassida rubiginosa Muller) is most effective at high levels on young plants. In nature, however, the latter two natural enemies are not synchronized with these susceptible stages, thereby reducing their effectiveness. Although Cleonus piger Scop., a root crown inhabitant, can result in plant death, regeneration of damaged vascular tissue can occur. Plants which emerge systemically infected with Puccinia punctiformis (Str.) Rohl. (rust) rarely survive the season. A matrix model simulating the effects on Canada thistle population dynamics by the natural enemies was applied.

No description available.

Colletotrichum coccodes (Wallr.) Hughes, a foliar pathogen of velvetleaf, is being developed as a bioherbicide. Formulation of living organisms for use as pest control products presents unique problems. This research has achieved the development of an adequate formulation of the pathogen by using kaolin clay or talcum powder (1:2.79 wt/wt) as the fillers to dry conidia. Formulated C. coccodes conidia stored at 4, 30C, or at room temperature in bags permeable to oxygen remained viable and able to infect velvetleaf plants at least six months in storage. Various reported germination stimulants increased germination of formulated conidia, although not significantly, whereas increasing concentrations of cutin resulted in subsequent decreases in germination and appressoria formation of fresh as well as formulated conidia. In controlled environment experiments, 14 day-old velvetleaf seedlings were severely diseased when stearic or oleic acids were added to conidia formulated in kaolin clay or talcum powder, respectively. Combinations of germination stimulants, cutinase and/or pectinase inducers did not significantly increase germination and appressoria formation of C. coccodes conidia. Germination of fresh and formulated conidia increased, although not significantly, with the addition of 1% sucrose.