ECONOMIC ANALYSIS OF CONTROLLING LEAFY SPURGE WITH SHEEP

Leafy spurge (Euphorbia esula L.), a widely established exotic, noxious, perennial weed, is a major threat to rangeland and wildland in the Upper Great Plains. Chemical, biological, and cultural control methods have limitations in their applicability and effectiveness in treating leafy spurge. However, many of the constraints prohibiting the use of herbicides, tillage, and biological controls do not apply to sheep grazing. Sheep grazing, while known to be effective in controlling leafy spurge since the 1930s, has lacked widespread adoption as a leafy spurge control. A deterministic, bioeconomic model, incorporating relationships between sheep grazing and leafy spurge control, grass recovery, and forage use by cattle, was developed to evaluate the economic viability of using sheep to control leafy spurge. Discounted annual control costs were compared to discounted annual control benefits over 5-year, 10-year, and 15-year periods. Various scenarios were developed depicting likely situations involving adopting a sheep enterprise or leasing sheep for leafy spurge control. Situational factors considered included fencing expenses, debt considerations, grazing values, infestation size, infestation canopy cover, rangeland productivity, and flock performance. Two levels of flock profitability, one based on a level of proficiency achieved by sheep ranches and one substantially lower than typically achieved in the sheep industry, represented best-case and worst-case situations, respectively. In the best-case situations, using sheep to control leafy spurge was economical in all of the control scenarios examined. However, in the worst-case situations, economics of using sheep to control leafy spurge were mixed across the scenarios examined. Leafy spurge control with poor sheep management, high fence expense, and unproductive rangeland generally was not economical. However, situations with low fencing costs, moderately productive rangeland, and poor sheep management resulted in less economic loss than no treatment. Although many of the key relationships tying leafy spurge control to grazing benefits remain unquantified, the economics of sheep grazing were positive across many of the scenarios evaluated in this study. Actual returns from leafy spurge control for most ranchers will likely fall between the two extremes examined. As a precaution, careful evaluation using site- and rancher-specific inputs would be recommended before implementing sheep grazing as a leafy spurge control method.Leafy Spurge, Weed Control, Sheep Grazing, Economics, Farm Management, Resource /Energy Economics and Policy,

PREDICTED FUTURE ECONOMIC IMPACTS OF BIOLOGICAL CONTROL OF LEAFY SPURGE IN THE UPPER MIDWEST

The Leafy Spurge Biological Control program was designed to use insects and plant diseases from the plant's original European habitat to control infestations in the United States. The widespread adoption of biological agents to combat leafy spurge and the initial success in reclaiming previously infested land has prompted an evaluation of the potential future economic benefits of the biological control of leafy spurge in the Upper Midwest. Based on expert opinion and historical data, leafy spurge in Montana, North Dakota, South Dakota, and Wyoming was projected to infest 1.85 million acres, of which, 65 percent was estimated to controlled with biological agents by 2025. Based on a survey of county weed board personnel, North Dakota and Wyoming are further advanced in the use of biological control than Montana and South Dakota. Recovery of rangeland outputs resulting from the biological control of leafy spurge was estimated to create $52.7 million in direct and secondary economic impacts. Biological control of leafy spurge on wildland was estimated to generate$5.6 million annually. By 2025, total economic impacts of the Leafy Spurge Biological Control Program were estimated at $58.4 million (1997 dollars) annually in the four-state region. An additional 876 full-time equivalent secondary jobs would be created as result of the program. Although the economic estimates generated are based on expert opinion and remain sensitive to assumptions regarding the future efficacy of the biological control of leafy spurge, initial evidence suggests the program will be an economic success regardless of the eventual level of control. The assessment of the economic value of the biological control of leafy spurge would benefit from incorporation of additional information as the overall understanding of the biological control process grows.biological control, leafy spurge, economic impacts, Upper Midwest, Resource /Energy Economics and Policy,

RANCH OPERATORS' PERCEPTIONS OF LEAFY SPURGE

A survey of 459 ranchers was conducted to evaluate managerial, institutional, and social factors that may affect the rate and extent of implementation of various leafy spurge (Euphorbia esula L.) controls in a five-county region in Montana, North Dakota, South Dakota, and Wyoming. Ranchers returned 187 questionnaires. Weeds were considered a greater problem for ranchers with leafy spurge than for those without leafy spurge; however, even among ranchers with leafy spurge, there was strong agreement that other ranching issues were of greater concern. Over 65 percent of the respondents indicated that weeds on their ranch were a `minor problem.' Leafy spurge was ranked as the most important weed. Nearly 60 percent of ranchers felt that using herbicides, biological agents, and grazing animals on leafy spurge were economical; however, only 25 percent of ranchers with leafy spurge felt those controls were `very effective.' A majority of ranchers with leafy spurge indicated plans to treat their infestations with herbicides and biological agents in the future. Reasons for not using various leafy spurge controls fell into environmental, educational, and financial categories. Ranchers depend heavily on their county extension agents and local weed control officers for information on weed control. Information on the effectiveness and economics of various controls was most requested by ranchers. The responses of ranchers to various statements on weed and range management indicated that ranchers, as a group, are generally very concerned about weeds in rangeland. Respondents generally felt it makes economic sense to control weeds in rangeland, and felt very strongly that not enough was being done to control weeds on public land. Ranchers realize the difficulty in controlling leafy spurge, but indicated they are still planning on fighting the weed in the future. Financial and educational constraints to adopting and using leafy spurge controls could be abated through university and governmental educational programs and through cost-share or other financial assistance.leafy spurge, control, rancher opinion, Farm Management, Resource /Energy Economics and Policy,

IMPEDIMENTS TO CONTROLLING LEAFY SPURGE IN THE NORTHERN GREAT PLAINS

Leafy spurge is an invasive noxious weed, which by definition means it is inordinately difficult to control. The objective of this report is to present the results of focus group meetings and personal interviews with ranchers, local decision makers, and public land managers to discover strategies to improve leafy spurge management. Participants in the interviews and focus group meetings managed property in Fallon, Carter, and Wibaux Counties of Montana; Golden Valley, Bowman, Billings, and Slope Counties of North Dakota; Harding County of South Dakota; and Crook County of Wyoming. Ranchers and local decision makers believe that leafy spurge control must become more proactive rather than reactive; current strategies are largely reactive. Interviews with ranchers and local decision makers revealed that a considerable gap in understanding how to control leafy spurge exists between researchers and those attempting to combat the weed. Interviewers often mentioned that they have been unable to eradicate leafy spurge, which indicates that the current mind set of ranchers and land managers needs to change to one focusing more on controlling and managing leafy spurge rather than eradication. Specific recommendations would include 1) reducing the current levels of herbicide application rates - which are often two to three times higher than rates recommended by weed scientists, 2) must appreciate that herbicides are but one tool in the battle against leafy spurge, 3) must understand that in many cases eradication of leafy spurge will not be possible - the goal should be trying to control it, and 4) rangeland rental rates need to reflect current levels of weed infestations. Records of weed infestations (e.g., acreage, location, rate of spread, attempts at control) on public lands are woefully inadequate. Cooperation between ranchers, county weed boards, and public land agencies could be improved to enhance the effectiveness of existing control programs. Weed control regardless of land ownership is important for ranchers, absentee landowners, and public agencies to effectively control leafy spurge. In general, ranchers and land managers need to generate a broader base of support for control of leafy spurge, since the weed attacks the entire ecosystem and is not just an agricultural problem.leafy spurge management, ranchers, county weed boards, public land managers, policy makers, Farm Management, Production Economics,

PERCEPTIONS OF LEAFY SPURGE AND EVALUATION OF THE TEAM LEAFY SPURGE PROJECT, BY PUBLIC LAND MANAGERS, LOCAL DECISION MAKERS, AND RANCH OPERATORS

Leafy spurge is an exotic, noxious, perennial weed which is widely established in the north central United States and is an especially serious problem in the northern Great Plains (Bangsund et al. 1999). In 1997, the Agriculture Research Service and Animal Plant Health Inspection Service, U.S. Department of Agriculture, initiated a major Integrated Pest Management (IPM) research and demonstration project to develop and demonstrate ecologically based IPM strategies that can produce effective, affordable leafy spurge control. In 1998 and 1999, a survey of ranchers and public land managers was conducted to evaluate managerial, institutional, and social factors that might affect the rate and extent of implementation of various control strategies. In 2001, a second survey of the same ranchers and public land managers was conducted to (1) assess any changes in land managers' perceptions of weed problems, control alternatives, and related issues, and (2) evaluate the impact of the TEAM Leafy Spurge project on the respondent's weed control practices. The impacts of noxious weeds on grazing operations, specifically leafy spurge, are not abating, and ranchers seem more aware than ever of the severity of the problem. A slightly larger percentage of respondents in 2001 view leafy spurge as a major problem and the most serious problem for grazing operations than in 1998 and 1999. Heightened awareness among landowners may also be linked to TEAM Leafy Spurge's efforts to inform landowners of the problem and offer affordable, effective weed management techniques. While the use of biological control methods, specifically flea beetles, has grown, herbicides continue to be the control practice of choice. While slightly fewer respondents reported using herbicides in 2001 than in 1998 and 1999, the vast majority of landowners plan to continue to use herbicides. Over 50 percent of respondents are using biological control, and over 76 percent of respondents indicated flea beetles were either somewhat or very effective in controlling leafy spurge. Nearly half of the respondents had heard of TEAM Leafy Spurge, and all TEAM Leafy Spurge demonstration sites, events, and publications were favorably rated. A large majority of the respondents agreed that the program had been effective in demonstrating and communicating leafy spurge treatment and control options. Based on the results of the 2001 survey, it would appear that the program has indeed made progress in communicating the type of information landowners need to address what continues to be a significant issue for grazing operations in the Midwest.leafy spurge, noxious weeds, weed management, rancher opinion, Land Economics/Use,

RANCH OPERATORS' PERCEPTIONS OF LEAFY SPURGE MANAGEMENT AND EVALUATION OF THE TEAM LEAFY SPURGE PROJECT

Leafy spurge is an exotic, noxious, perennial weed which is widely established in the north central United States and is an especially serious problem in the northern Great Plains (Bangsund et al. 1999). In 1997, the Agriculture Research Service and the Animal and Plant Health Inspection Service, U.S. Department of Agriculture, initiated a major Integrated Pest Management (IPM) research and demonstration project to develop and demonstrate ecologically based IPM strategies that can produce effective, affordable leafy spurge control. In 1998 and 1999, a survey of ranchers and public land managers was conducted to evaluate managerial, institutional, and social factors that might affect the rate and extent of implementation of various control strategies. In 2001, a second survey of the same ranchers and public land managers was conducted to (1) assess any changes in land managers' perceptions of weed problems, control alternatives, and related issues, and (2) evaluate the impact of the TEAM Leafy Spurge project on the respondent's weed control practices. The impacts of noxious weeds on grazing operations, specifically leafy spurge, are not abating, and ranchers seem more aware than ever of the severity of the problem. A slightly larger percentage of respondents in 2001 view leafy spurge as a major problem and the most serious problem for grazing operations than in 1998 and 1999. Heightened awareness among landowners may also be linked to TEAM Leafy Spurge's efforts to inform landowners of the problem and offer affordable, effective weed management techniques. While the use of biological control methods, specifically flea beetles, has grown, herbicides continue to be the control practice of choice. While slightly fewer respondents reported using herbicides in 2001 than in 1998 and 1999, the vast majority of landowners plan to continue to use herbicides. Over 50 percent of respondents are using biological control and over 76 percent of respondents indicated flea beetles were either somewhat or very effective in controlling leafy spurge. Nearly half of the respondents had heard of TEAM Leafy Spurge, and all TEAM Leafy Spurge demonstration sites, events, and publications were favorably rated. A large majority of the respondents agreed that the program had been effective in demonstrating and communicating leafy spurge treatment and control options. Based on the results of the 2001 survey, it would appear that the program has indeed made progress in communicating the type of information landowners need to address what continues to be a significant issue for grazing operations in the Midwest.leafy spurge, noxious weeds, weed management, rancher opinion, Crop Production/Industries,

ASSESSMENT OF THE EXTENT AND SUCCESS OF LEAFY SPURGE BIOLOGICAL CONTROL AGENTS

Leafy spurge is an exotic, noxious, perennial weed which is widely established in the north central United States and is an especially serious problem in the northern Great Plains. In 1997, the Agricultural Research Service and the Animal and Plant Health Inspection Service of the U.S. Department of Agriculture (USDA), initiated a major Integrated Pest Management (IPM) research and demonstration project, TEAM Leafy Spurge (TLS), to develop and demonstrate ecologically based IPM strategies that can produce effective, affordable leafy spurge control. A key component of the project was to expand the use of biological control (biocontrol) agents, specifically flea beetles. To assess the level of insect establishment and the level of current and perceived future control of leafy spurge, a mail survey was conducted of 468 individuals who obtained biocontrol agents (insects) at TLS-sponsored events, as well as County Weed Boards in North Dakota, South Dakota, Montana, and Wyoming. Respondents reported basic information about the number and characteristics of release sites, characteristics of leafy spurge stands, as well as the level of control to date and perceived level of eventual control. Substantial numbers of landowners and County Weed Boards have utilized biocontrol agents as part of their leafy spurge control efforts, as well as collected flea beetles from release sites for redistribution. Respondents indicated biocontrol efforts are affecting at least some level of control and, in some cases, reported substantial reductions in spurge stands.leafy spurge, biological control, Apthona lacertosa/czwalinae, flea beetle, noxious weeds, weed management, Resource /Energy Economics and Policy,

Control of flower development in Arabidopsis thaliana by APETALA1 and interacting genes

Mutations in the APETALA1 gene disturb two phases of flower development, flower meristem specification and floral organ specification. These effects become manifest as a partial conversion of flowers into inflorescence shoots and a disruption of sepal and petal development. We describe the changes in an allelic series of nine apetala1 mutants and show that the two functions of APETALA1 are separable. We have also studied the interaction between APETALA1 and other floral genes by examining the phenotypes of multiply mutant plants and by in situ hybridization using probes for several floral control genes. The results suggest that the products of APETALA1 and another gene, LEAFY, are required to ensure that primordia arising on the flanks of the inflorescence apex adopt a floral fate, as opposed to becoming an inflorescence shoot. APETALA1 and LEAFY have distinct as well as overlapping functions and they appear to reinforce each other's action. CAULIFLOWER is a newly discovered gene which positively regulates both APETALA1 and LEAFY expression. All functions of CAULIFLOWER are redundant with those of APETALA1. APETALA2 also has an early function in reinforcing the action of APETALA1 and LEAFY, especially if the activity of either is compromised by mutation. After the identity of a flower primordium is specified, APETALA1 interacts with APETALA2 in controlling the development of the outer two whorls of floral organs

Genetic resources collections of leafy vegetables (lettuce, spinach, chicory, artichoke, asparagus, lamb’s lettuce, rhubarb and rocket salad): composition and gaps

Lettuce, spinach and chicory are generally considered the main leafy vegetables, while a fourth group denoted by ‘minor leafy vegetables’ includes, amongst others, rocket salad, lamb’s lettuce, asparagus, artichoke and rhubarb. Except in the case of lettuce, central crop databases of leafy vegetables were lacking until recently. Here we report on the update of the international Lactuca database and the development of three new central crop databases for each of the other leafy vegetable crop groups. Requests for passport data of accessions available to the user community were addressed to all known European collection holders and to the main collection holders located outside Europe. Altogether, passport data of 17,530 accessions from a total of 129 collections were collected. The four separate databases were made available on line via a common entry page accessible at http://documents.plant.wur.nl/cgn/pgr/LVintro/. Based on a literature study, an analysis of the gene pool structure of the crops was performed and an inventory was made of the distribution areas of the species involved. The results of these surveys were related to the contents of the newly established databases in order to identify the main collection gaps. Priorities are presented for future germplasm acquisition aimed at improving the coverage of the crop gene pools in ex situ collections

Origins of neotropical leafy Hepaticae

The neotropical hepatic flora, predominantly constituted by members of the Jungermanniales and Metzgeriales, includes a disproportionate number of genera which are endemic (over 38) and a number which evidently originated here but have shown slight and in a geological sense, modern dispersal by solitary species. Endemism is confined almost to the Jungermanniales; it is to a large degree of a unique sort: confined to highly apomorphic derivatives, often extremely reduced, sometimes confervoid or thalloid (aside from 'normal' sexual branches). These endemics are derivatives of basically cool-Gondwanalandic suborders, chiefly Lepidoziineae and Cephaloziineae which, in the Antipodes today include a wide range of plesiomorphic taxa. The highest proportion of endemic genera, often stenotypic (1-3 species each) occurs in the upper montane zone: from upper Andean forest to páramo, to the edge of permanent snow and ice; a smaller number occurs at upper elevations of the Guyana Shield, but more occur in the riverine systems that dissect this shield. The taxa found there (i.a., Zoopsidella, Pteropsiella, Schusterolejeunea, Cephalantholejeunea) are among the most apomorphic of all hepatics. The amount of endemism is shown to be higher than in any comparable region of the globe. It is assumed that this is owing to: (a) isolation, exceeding 40 m.y. and probably exceeding 60 m.y.; (b) continuous tectonic activity, preserving the 'raw' and 'pioneer' habitats which are necessary for the survival of 'fugitive', 'shuttle' and other types of pioneer taxa; (c) the antiquity of the Guyana Shield and its riverine system; (d) creation of striking ecological gradients, many biotic islands; (e) fluctuation in extent and degree of isolation of these 'islands', leading to (f) rapid evolution due to genetic drift and perhaps enhanced selection pressures. It is concluded that part of the complexity of the flora is due to preservation of some elements on the old Guyana Shield but most is due to relatively rapid evolution during Tertiary times. A final contributing element has been the fact that movement of the South American plate has been primarily from east to west, so that the relevant land area has not been rafted into regions with very different climatic parameters: the degree of extinction seen in, e.g., India and Australia is not evident here. It is concluded that the amount of endemism seen, and its extreme kinds, 'need' in excess of the 40-60 m.y. time span which seems available. In particular, the large number of high elevation endemics, some (such as Ruizanthus) very isolated, cannot be satisfactorily explained by assuming their evolution in the few million years available since alpine regions were created by the rise of the Andes. It is almost necessary to conclude that limited 'pre-Andes' must have existed and that the ancestors of the isolated taxa seen today in alpine loci in Colombia and Venezuela originated elsewhere. The other side of the outlined scenario is that with the near-total isolation of tropical America until the Andes were elevated, and until the Pliocene connection to North America arose, one would expect to see few and scattered intruders from cool-Gondwanalandic areas and from Laurasia. The modern flora reflects exactly this