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Melinda A. Miller-Butler, Barbara J. Smith, Kenneth J. Curry, and Eugene K. Blythe

anthracnose-resistant germplasm by Miller-Butler et al. (2018) . Disease severity refers to the amount of plant tissue that is diseased (necrotic) and may be expressed as the percentage of plant area destroyed by a pathogen. Percentage or numerical disease

Open access

Craig J. Frey, Xin Zhao, Jeffrey K. Brecht, Dustin M. Huff, and Zachary E. Black

microclimate conditions, and 2) determine the high tunnel and grafting effects on plant foliar disease severity and RKN infestation in an organic tomato production system. Materials and Methods Plant material. The organic tomato trial was performed during

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Rodulfo O. Pacumbaba Jr. and Caula A. Beyl

CD-ROM technology, scanners, and image capture software have enabled an alternate approach to determining disease severity. When estimating disease damage, information on disease severity may be as important as information on disease incidence. Disease incidence is the proportion of leaves infected on each tree; disease severity is the number of lesions or amount of tissue damage per tree. The Mielke and Langdon scale was used to determine the incidence of dogwood anthracnose on dogwoods under physiological stress; the CD-ROM system was used to determine the severity of the disease. Dogwood seedlings were exposed to four shade and three water levels for 12 weeks. Leaf images were stored on a photo-CD for image analysis. Water availability at 100% water-holding capacity significantly increased disease severity on dogwood leaves inoculated in vitro. The system allowed detection of a significant effect of water availability on susceptibility of the leaf to dogwood anthracnose that was not detected when incidence of infection was evaluated on a whole-plant basis

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A.D. Brede

A field study was conducted to evaluate the effect of tall fescue (Festuca arundinacea Schreb.) cultivar, seeding rate, N fertilization rate, and cutting height on the severity of dollar spot (Lanzia and Moellerodiscus spp.) disease incidence. All possible two-factor interactions among these four management factors were statistically significant when averaged over the 2 years of study. Disease severity tended to be lowest at low fescue seeding rate (2100 pure-live seeds/m*) at the lower (19 mm) height of cut. `Mustang', the turf-type cultivar with improved density, was more susceptible to dollar spot than `Kentucky-31', the common-type cultivar.

Open access

Luis A. Rivera-Burgos, Emily Silverman, Nebahat Sari, and Todd C. Wehner

for resistance to GSB ( Gusmini et al., 2005 ). The scale has been used in genetic analyses of large numbers of plants tested in multiple environments ( Gusmini et al., 2017 ). Another method of measuring disease severity involves the area under the

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Stephen N. Wegulo and Miguel Vilchez

day the cultivars were transplanted and served as a source of inoculum. Average disease severity on these plants at the time they were placed around the benches was 3 on a scale of 0 to 5 (0 = no symptoms; 1 = 1% to 20% of foliage covered with powdery

Open access

Andre Luiz Biscaia Ribeiro da Silva, Joara Secchi Candian, Elizanilda Ramalho do Rego, Timothy Coolong, and Bhabesh Dutta

et al., 2004 ). The AUDPC, which characterizes the progress of cabbage BR, was calculated from disease severity ratings taken on 0, 7, 14, 21, 28, 35, 58, 64, and 69 DPI in Fall 2018 and 0, 6, 13, 20, 27, 34, 41, and 49 DPI in Spring 2019. The AUDPC

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Sharon M. Tusiime, Gail R. Nonnecke, Dorothy M. Masinde, and Helen H. Jensen

, staking, and mulching and their impact on yield, disease severity, and gross margin. Evaluating horticultural practices for sustainable tomato production will enable small-landholder farmers to benefit from increased farm income and personal consumption

Free access

Yunwen Wang, Huangjun Lu, Richard N. Raid, Gregg S. Nuessly, and Georgy Faroutine

scored for disease incidence and severity. The disease incidence was calculated by the percent of infected plant among all plants in each row. The disease severity of a plant was evaluated using the 0–4 rating system as reported by Bull et al. (2007

Open access

Subhankar Mandal and Christopher S. Cramer

FBR disease incidence ( Lopez and Cramer, 2002 , 2004 ), and resistance or tolerance to pink root disease ( Phoma terrestris E.M. Hans.), which is positively correlated with FBR disease severity ( Cramer, 2000 ). An FBR-tolerant control, ‘Serrana