A sustainable approach to Phytophthora-infested landscape beds: the search for tolerant or resistant annuals and herbaceous perennials

Abstracts from the April 12-14, 2019 MASC Conferenc

Economic Analysis of Pruning Grafted Fresh-market Tomato Plants under Field Conditions in North Carolina

Grafted tomato (Solanum lycopersicum L.) plants have the potential to increase yield in the absence of soilborne disease; however, success is dependent on geographic location and rootstock–scion combination. Pruning axillary shoots on field-grown tomato plants is a standard practice for fresh-market production in the southeastern United States, although few studies have evaluated the effects of pruning grafted tomato plants. In this study, we evaluated six field grown tomato rootstock–scion combinations and their nongrafted counterparts, pruned or not pruned, over the course of 2 years at one location in North Carolina. Total yield, fruit size, variable cost of inputs, and net return data were analyzed. In both years of the study, cultivars Mountain Gem and Jolene had high yield of jumbo and extra-large fruit when grafted onto ‘Maxifort’ or ‘Beaufort’ rootstock. Yield was higher (P < 0.0001) for plants that were grafted and not pruned compared with nongrafted pruned plants (grower standard). Net return from the treatment where plants were grafted onto ‘Maxifort’ rootstock and not pruned was greater than that from the grower standard practice, although this was not the case in both years of the study. The variable cost of growing grafted plants that were not pruned was always greater than that of the grower standard practice due to the greater cost of transplants and labor associated with harvest. The results from this study emphasize the importance of evaluating a small number of prospective rootstock–scion combinations on-farm and considering the balance between higher input costs of the grafted plants and potential increased yields before planting an entire field

Variable Yield Responses among Grafted and Nongrafted Late blight–resistant Tomato (Solanum lycopersicum L.) Hybrids in North Carolina

Host resistance is an environmentally and economically sustainable disease management strategy that may be especially beneficial to small-scale and organic growers for whom other management tools such as synthetic pesticides are too costly or not permitted. In western North Carolina, the demand for vine-ripened tomatoes (Solanum lycopersicum L.) from local and organic farms has led to the development of cultivars bred for resistance to geographically relevant diseases, including late blight of tomato, which causes rapid defoliation and lesions on fruit. Grafting tomato plants has the potential to increase plant vigor and yield; however, this effect is known to be dependent on multiple factors, including scion and geographic location. In this study, we evaluated the yield response of one determinate (‘Mountain Gem’) and four indeterminate (‘Mountain Heritage’, ‘Mountain Girl’, ‘Mountain Rouge’, and ‘NC10291’) late blight–resistant tomato cultivars, grafted on tomato rootstock ‘Maxifort’ or nongrafted, on a commercial farm and at two research facilities in western North Carolina. Yield of marketable fruit from grafted plants was greater than that from nongrafted plants at one location (P = 0.008); however, yield response of each cultivar, grafted or not grafted, differed by location. Yield was consistently greater from ‘Mountain Gem’ plants than other cultivars, and grafted ‘Mountain Gem’ plants had greater yields later in the season at two locations than nongrafted plants. Because of the late planting date intended to expose cultivars to the late blight pathogen, the full yield potential of the indeterminate cultivars was not realized at all locations. Disease severity caused by Verticillium wilt (Verticillium dahliae Kleb., Verticillium albo-atrum Reinke & Berthold) was lowest for cultivar Mountain Heritage at two of three locations. Results from this study emphasize the importance of conducting evaluations of grafted tomato plants at multiple locations, including on farm, to optimize the benefits associated with their use

Environment and Sustainable Development

The book has been prepared and published with the support of the Norwegian Financial Mechanism Project LV0044 "Development of environmental science study content and study materials

Health-status outcomes with invasive or conservative care in coronary disease

BACKGROUND In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline