Download or read book Interactive Effects of Plant plant Competition and an Introduced Biocontrol Agent on Yellow Starthistle Centaurea Solstitialis Seed Production written by Benjamin Robert Janes and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Yellow starthistle (YST) is an annual invasive weed throughout the western United States. Several efforts have been made to control YST population spread. One of the most notable of these was the introduction of a European weevil species, Eustenopis villosus, which parasitizes developing YST flower heads. Past studies have demonstrated that late-season forbs with growth patterns similar to YST can also suppress its growth in experimental plant communities. This study examined the effects of competitive interactions between tarweed species (a group of late-season forbs) and YST individuals through the period of YST flowering using log response ratios. The study also examined the interplay between these competitive interactions and the effects of E. villosus on YST individual seed production by statistically controlling for E. villosus infestation in a method similar to ANCOVA. E. villosus infestation generally interacted weakly and positively with plant competitive effects--YST individuals that grew larger and escaped plant competition were also able to escape the effects of E. villosus infestation to a degree, and were able to produce more seeds. However, stronger negative interactions were found between the effects of the strongest water competitors on YST seed production and E. villosus later in the flowering period. As the effects of plant competition for water manifested later during the flowering period, E. villosus infestation may have been effected by YST quality.
Download or read book Effects of Plant Competition and Soil Water Availability on Yellow Starthistle Centaurea Solstitialis L Growth Along a Slope Gradient written by Lee Eubank and published by . This book was released on 2005 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Defoliation on Yellow Starthistle Centaurea Solstitialis L Reproductive Capacity written by Stacy Schumacher and published by . This book was released on 2001 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yellow starthistle (Centaurea solstitialis L.) is an introduced Asteraceae that has become established on 10 million acres in the Pacific Northwest and California. This weed functions as an annual or short-lived perennial and depends on seeds for reproduction. Strategies of control that reduce plant fitness or lower seed production or viability may help limit the rate of spread of yellow starthistle. Previous work has shown that grazing and mowing can influence seed production. This study tested the hypothesis that proper timing and frequency of defoliation can reduce the number and viability of seeds produced. The study was conducted in Umatilla County, Oregon using a randomized block design with 4 replications of each of 4 defoliation treatments: (1) single defoliation at the bolting stage; (2) single defoliation at the bud stage; (3) two defoliations, once at the bolting stage and again at the bud stage; (4) non-defoliated control. Each of 4 blocks consisted of a 12 x 12 m area, with 16 plots measuring 3 x 3 m. Plants were defoliated at ground level using a gas-powered string-type mower. Response measurements were collected at the end of the growing season (September) following potential regrowth and included: (1) number of seedheads per plant; (2) number of seeds per seedhead; (3) number of seeds per plant; (4) number of seeds m−2, (5) seed viability (% germination rates). Supporting measurements included: seedhead diameter; plant height, number of branches per plant; pre-dawn xylem pressure; soil moisture; and documentation of 5 biological control insect species. A single defoliation at bolting resulted in fewer seeds per seedhead, and fewer seeds per plant than non-defoliated controls. A single defoliation at the floral bud stage or repeated defoliation (bolting and again at the bud stage) resulted in equally fewer seeds per plant and fewer seeds m−2 compared to non-defoliated controls. There was no statistical difference in percent germination of seeds among treatments. Defoliation had no effect on the infestation rates of seedheads by biological control insects. A second study examined nutrient content of yellow starthistle during 6 phenological stages from sites in Union, Baker and Umatilla Counties, Oregon during each of 2 years. Acid detergent fiber, lignin, cellulose and neutral detergent fiber contents increased through phenological development. Crude protein ranged from 16.7 to 5.0%. In Vitro dry matter digestibility ranged from 84.8% to 57.0%. Mineral nutrients P, K, CA, Mg, Mn, Fe, Cu, Zn, and Na were analyzed and determined to be adequate for maintenance needs of ewes.
Download or read book Environmental Site Conditions and Habitat Characteristics Influence Biocontrol Insects of Yellow Starthistle Centaurea Solstitialis in Washington USA written by Steven Edward Woodley and published by . This book was released on 2018 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is comprised of three separate field studies which took place in eastern Washington State and occurred between 2014 through 2017. The first, a 2-year (2014-2015) field study quantified the effect of environmental factors on the overwintered Eustenopus villosus (Boheman) and Larinus curtus (Hochhut) adults in relation to the phenology of Centaurea solstitialis L. (Asteraceae: Cardueae). Results suggested that the appearance and increase in frequency of the overwintered E. villosus and L. curtus adults was likely a function of warming temperatures. Both species' decline in frequency was likely a function of the weevils completing their life cycle in synchrony with the phenological advancement of C. solstitialis and decline of abundant breeding and foraging sites (buds and flowers). The second 2-year field study (2014-2015) examined percent infestation of E. villosus and L. curtus and the species percent seed consumption in Washington compared to studies in California and Greece to determine if differences in macroclimates influence the efficacy of the species. Findings suggested that differences in macroclimates does not appear to influence either species percent infestation or seed consumption. The third, a one-year field study (2017) examined the influence of physical environmental conditions and habitat characteristics on the composition of colonization by biocontrol insects of C. solstitialis biocontrol insects. In addition, this research examined whether different colonization by C. solstitialis biocontrol insects at a site created differences in the percent of C. solstitialis flowerheads infested and seed consumption in the southeastern corner of Washington. Results indicate that different environmental conditions and habitat characteristics which create the effective environment for the insects and reflected by the different plant associations and C. solstitialis seed production between sites, influence the composition of colonization by C. solstitialis biocontrol insects. Different effective environments create opportunity for physiological selection by biological insects of C. solstitialis . In addition, consumptive competition, seasonal emergence, and/or the timing of ovipositing by the overwintering generations may also play a significant role in the composition of colonization. Sequentially, differences in the composition of colonization create differences in the efficacy of control C. solstitialis by biocontrol insects.
Download or read book The Response of Yellow Starthistle and the Insect Biological Control Agents Eustenopus Villosus and Chaetorellia Succinea to the Rust Puccinia Jaceae Var Solstitialis written by Jon M. O'Brien and published by . This book was released on 2008 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Species Diversity and Soil Water Dynamics on the Invasion by Yellow Starthistle Centaurea Solstitialis Into Established California Central Valley Plant Communities written by Stephen Looysen Young and published by . This book was released on 2007 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Yellow Starthistle written by Carri Beth Benefield and published by . This book was released on 1998 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multispecies Interactions and Demography of the Invasive Thistle Centaurea Solstitialis in California written by Sarah M. Swope and published by . This book was released on 2009 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biology and Biological Control Agents of Yellow Starthistle written by Cynthia Jette and published by . This book was released on 1999 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Yellow Starthistle Biology and Control written by C.D. Thomsen and published by UCANR Publications. This book was released on 1996 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Population level Compensation Foils Effects of Massive Seed Loss Caused by Biocontrol Agents written by Julie Garren and published by . This book was released on 2006 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Yellow Starthistle Centaurea Solstitialis written by John Theodore Rusmore and published by . This book was released on 1998 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enhanced Biological Control of Yellow Starthistle and Tumbleweed Russian Thistle written by Lincoln Smith and published by . This book was released on 2006 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis of the Distribution of Seed Head Insects on Yellow Starthistle Centaurea Solstitialis written by Rosalie Ann Yacoub and published by . This book was released on 2005 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Ecology and Management of Yellow Starthistle in Annual and Perennial Grassland Communities written by Stephen Frederick Enloe and published by . This book was released on 2002 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hybridization Between Yellow Starthistle Centaurea Solstitialis and Meadow Knapweed Centaurea X Moncktonii written by John Miskella and published by . This book was released on 2014 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Centaurea solstitialis L. (yellow starthistle) and C. x moncktonii Britt. (meadow knapweed) are members of the genus Centaurea in the Asteraceae family. Both species have become serious management concerns as invasive species in North America, often displacing native vegetation and costing land managers millions of dollars to eradicate. Seven plants were found in southwestern Oregon that appear to be hybrids between C. solstitialis and C. x moncktonii. These plants were identified as hybrids based on bract shape, flower color, and the presence of the putative parent species at the same sites. Hybridization between these two species may present potential management problems, such as the hybrids developing into a viable species or gene flow between the parent species. Meadow knapweed originated through hybridization and colonized a larger range than either of its parent species. If hybrids produce viable pollen or fertile seed, backcrossing with one of the parent species could transfer alleles from one parent species to the other. Hybrids have the potential to transgress parent species for some traits and show increased fitness relative to the parent species. The putative C. solstitialis x C. moncktonii hybrids were identified based primarily on intermediate morphological traits. To test the hypothesis that these species can produce hybrids, controlled crosses between yellow starthistle and meadow knapweed were attempted. These crosses produced thirty hybrids that fit the morphological description used by Roché and Susanna (2010) to identify plants as C. solstitialis x C. moncktonii hybrids. The hybrids generated from the controlled crosses germinated from seeds that came from yellow starthistle plants. Genome size, measured using flow cytometry, and four quantifiable morphological characters were measured on the putative hybrids, hybrids generated through controlled crossing, and the parent species. When the group means were compared, there was no significant difference between the putative hybrids and the hybrids generated through controlled crossing for any of the characters. Both putative and artificial hybrids were backcrossed with the parent species to determine the likelihood of backcrossing. Backcrossing did occur, with the hybrids serving as both maternal parent and pollen parent at very low rates (
Download or read book Integrated Management of Yellow Starthistle Centaurea Solstitialis at Fort Hunter Liggett Monterey County California written by Jessica Renee Miller and published by . This book was released on 2003 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
