Cercospora beticola survives as stromata in infected crop residue. Spores produced on these survival structures serve as primary inoculum during the next cropping season. This study was conducted to determine how long C. beticola can survive at different soil depths, the mechanism of inoculum dispersal, and the primary infection site in sugar beet. Longevity of C. beticola was studied over a 3-year period under field conditions at Fargo, ND. C. beticola-infected leaves were placed at depths of 0, 10, and 20 cm and retrieved after 10, 22, and 34 months. Survival of C. beticola inoculum declined with time and soil depth. Inoculum left on the soil surface, 0 cm in depth, survived the longest (22 months) compared with that buried at 10 cm (10 months) and 20 cm (10 months). C. beticola dispersal from the primary source of inoculum was studied in the field for three growing seasons. Sugar beet plants were surrounded with plastic cages with and without ground cover, or exposed with and without ground cover. Significantly higher disease severity was observed on exposed plants than caged plants with or without ground cover, suggesting that wind was the major dispersal factor for C. beticola inoculum. The primary infection site by C. beticola was determined in a greenhouse study. Leaves, roots, and stems of healthy sugar beet plants were inoculated with C. beticola. Cercospora leaf spot symptoms were observed only on plants that were leaf inoculated, suggesting that the leaf was the primary infection site for C. beticola.
Purpose Serious non-AIDS (SNA) diseases are important causes of morbidity and mortality in the HAART era. We describe development of standard criteria for 12 SNA events for Endpoint Review Committee (ERC) use in START, a multicenter international HIV clinical trial. Methods SNA definitions were developed based upon the following: (1) criteria from a previous trial (SMART), (2) review of published literature, (3) an iterative consultation and review process with the ERC and other content experts, and (4) evaluation of draft SNA criteria using retrospectively collected reports in another trial (ESPRIT). Results Final criteria are presented for acute myocardial infarction, congestive heart failure, coronary artery disease requiring drug treatment, coronary revascularization, decompensated liver disease, deep vein thrombosis, diabetes mellitus, end-stage renal disease, non-AIDS cancer, peripheral arterial disease, pulmonary embolism, and stroke. Of 563 potential SNA events reported in ESPRIT and reviewed by an ERC, 72% met “confirmed” and 13% “probable” criteria. Twenty-eight percent of cases initially reviewed by the ERC required follow-up discussion (adjudication) before a final decision was reached. Conclusion HIV clinical trials that include SNA diseases as clinical outcomes should have standardized SNA definitions to optimize event reporting and validation and should have review by an experienced ERC with opportunities for adjudication.
Purpose-Describe processes and challenges for an Endpoint Review Committee (ERC) in determining and adjudicating underlying causes of death in HIV clinical trials.Method-Three randomized HIV trials (two evaluating interleukin-2 and one treatment interruption) enrolled 11,593 persons from 36 countries during 1999-2008. Three ERC members independently reviewed each death report and supporting source documentation to assign underlying cause of death; differences of opinion were adjudicated.
Management of Cercospora leaf spot, caused by Cercospora beticola, is necessary for the economic production of sugar beet (Beta vulgaris). The objectives of this study were to evaluate the impact of two relative humidity thresholds (87 and 90%) on the daily infection values (DIVs) used to determine when fungicide applications were required, to determine whether current Cercospora management recommendations for northern areas of Minnesota and North Dakota could be used by growers in the southern areas of these states, and to compare the utility of calendar-based fungicide applications with the Cercospora management model. Research was conducted in Breckenridge, MN and St. Thomas, ND in 2003 and 2004. Fungicide applications significantly (P = 0.05) reduced maximum disease severity (ymax) and area under the disease progress curve (AUDPC) when compared with the nontreated control at both locations during 2003 and 2004. Fungicides applied according to DIVs calculated at RH ≥ 87% or RH > 90% gave similar results. The mandatory second fungicide application 14 days after the first application for southern areas did not significantly decrease disease severity or AUDPC, or improve root yield or recoverable sucrose compared with treatments without the mandatory application. This research illustrates that a DIV calculated at RH ≥ 87% would result in similar timing of fungicide applications compared with DIVs calculated at RH > 90%. The results further show that the recommendation of fungicide applications at initial symptom and subsequent applications based on DIV and disease severity should be used for both northern and southern growers. Finally, this research showed that fungicide applications based on the Cercospora management model provided similar, effective disease control with fewer fungicide applications compared with calendar-based applications.
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