Progress 10/01/03 to 09/30/09

Outputs
OUTPUTS: There were three major objectives of the project that determined the yield loss caused by the rusts of wheat, sheath blight disease of rice and brown rust of sugarcane. Those objectives have been met and the results will be discussed in the Outcome/Impacts section that follows. The objectives were researched over the life of the project using the prescribed techniques set forth in the original proposal. Techniques were similar for each project objective measuring yield losses over the life of the crop. The results have been analysed statistically and have been or will be presented within days of this report. For example, the results of the brown rust of sugarcane have been presented internationally at the International Symposium for Pest Management in Glasgow, Scotland, UK in 2008, regionally at the American Society of Sugarcane Technologists and statewide at two Extension-Research training meetings and 15 sugarcane field days. Additionally the results have been published in Plant Disease, a journal of the American Phytopathological Society (APS). The wheat rust results have been presented at the Mid-South Association of Wheat Scientists annual meeting in Olive Branch, MS, in five Extension agent training sessions and at two regional small grain field days held at research stations in Alexandria and Winnsboro during 2008 and 2009, respectively. These results will be published soon in abstract form and have been presented to the faculty and students of the Department of Plant Pathology and Crop Physiology, LSU AgCenter in a Fall, 2009 seminar. A draft of the results for publication in Plant Disease will soon be complete and ready for internal review and submission to the journal. The results of the rice sheath blight yield loss study will be presented at the Southern Division, APS on February 8, 2010, but have been presented to Extension Agents and rice producers eight times in agent training and field day settings. The manuscript for journal publication will be completed soon. PARTICIPANTS: Dr. Jeff Hoy, Sugarcane Plant Pathologist, Department of Plant Pathology and Crop Physiology, LSU AgCenter. Jeff's role was to assist with scouting sugarcane to determine the best possible location to do the research on brown rust of sugarcane. Additionally, he helped with the fungicide application and data analysis. Dr. Donald Groth, Rice Plant Pathologist, Rice Research Station, LSU AgCenter, Crowley, LA. Dr. Groth provided the plot space and planted the rice test for the research. At season's end he had the test harvested. Dr. Boyd Padget, Plant Pathologist, Macon Ridge Research Center, LSU AgCenter, Winnsboro, LA. Boyd's role was to plant and harvest the wheat test at his off-campus location each year of the project. Dr. Steve Harrison, Wheat Breeder, School of Plant, Environment and Soil Systems, LSU AgCenter. Steve provided plot space, planted and harvested the test. The results of this work have provided information used in local regional, national and international presentations. Training, field day presentations, extension publications and professional journal articles have resulted from this work. Section 18 (FIFRA) opportunities have been pursued as an offshoot of this research. Growers are now better able to make educated decisions about disease management needs for their crops, encouraging appropriate management techniques and judicious use of fungicides when needed. TARGET AUDIENCES: The target audiences for this work were: sugarcane, rice and wheat growers in Louisiana and surrounding areas, Extension Agents, crop consultants, graduate students, plant pathology faculty, plant pathology research and extension workers, epidemiologists, crop loss assessment enthusiasts, risk management professionals, crop insurance industry, and commodity traders. PROJECT MODIFICATIONS: Due to project termination, no modifications are necessary.

Impacts
Yield losses due to brown rust in sugarcane have been defined during the course of the project as significant although the brown rust epidemic was described as moderate. Losses of nearly 1300 pounds of sugar per acre were measured in yield loss studies. Variety shifts from highly susceptible to less susceptible have reduced the overall impact to the industry, yet individual susceptible varieties that still have desired cultural advantages are grown. Due to the culture of sugarcane (three- to four-year growing cycles) growers are not able to shift varieties quickly thus resulting in a significant percentage of susceptible germplasm growing in production fields. Fungicide use is being considered with the submission of a Section 18 exemption of FIFRA to the Environmental Protection Agency. Wheat leaf rust yield loss measurements were used in the continued development and refining of a disease management guide and decision aid for growers. Losses over the life of the project were 26.1 bushels per acre or a loss of 46.4 percent for the susceptible, moderate yielding variety McCormick and 19.1 bushels per acre or a loss of 26.1 percent for the intermediately susceptible, higher yielding variety AGS 2000. It was determined that the decision aid developed from this project proved acceptable but continued refining was necessary. Rice sheath blight yield loss results have continued to aid in better management of the disease for growers. Results were included in the revision of the rice pathology section of the Louisiana Rice Production Handbook. Yield loss estimates are made annually but accurate measurements were not determined until this study. Fungicides were used a tool to influence sheath blight development in small plots. Applications were made with the aid of CO2 - pressurized sprayers delivering 93L/ha of solution at various times to halt or delay disease development to determine the affect of disease development on yield at different growth stages. Early disease development on enclosed canopy rice reduced yield greater than epidemics that were halted until late stages of crop development. Yield losses ranged from 7.83% for heading stage development (late developing disease), 16.65% for boot stage development (intermediate developing disease) to 28.63% for green ring stage development (early developing disease).

Publications

• Groth, D. E., Rush, M. C. and Hollier, C. A. 2009. Disease management. Pages 72-92 in: Louisiana Rice Production Handbook. Louisiana State University Agricultural Center. 128 pages.
• Hollier, C.A. and J.W. Hoy. 2008. The influence of brown rust (Puccinia melanocephala) on sugarcane yield. Phytopathology 98:S211.
• Hoy, J. and Hollier, C.A. 2009. Effect of brown rust on yield of sugarcane in Louisiana. Plant Dis. 93:1171-1174.
• Padgett, G.B., Harrison, S.A., Colyer, P, Mascagni, H.J. and Hollier, C.A. 2006. Managing stripe rust in Louisiana. Louisiana Agriculture 49 (4): 15-16.
• Hollier, C.A. and J.W. Hoy. 2007. Yield losses due to brown rust (Puccinia melanocephala) in sugarcane. Congress Proceedings 2:808-809. XVI International Plant Protection Congress, Glasgow, UK.
• Hollier, C.A. and D.E. Groth. 2010. Yield loss associated with sheath blight disease of rice. Absr. Plant Disease: 94:000.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Based on work from this project, yield losses due to brown rust disease of sugarcane were determined. These results specifically measure yield and quality losses whereas previously losses were estimated by "educated" guesses. Additionally, previous loss estimates were inaccurate determining that yield reduction due to brown rust was "negligible." These results differ. It has been determined that the results will benefit growers and agri-business community within Louisiana. Specific techniques and procedures of the project have been used in other research yield loss projects, have been used for developing Section 18 (of FIFRA) petitions for Headline fungicide and have been shared with growers by presentations at seven field days and three grower meetings. Currently, one refereed article is in review and other updates may be found through extension online. PARTICIPANTS: Dr. Jeff Hoy, Professor, Plant Pathology, Department of Plant Pathology and Crop Physiology. Dr. Hoy assisted in the research component of this project. TARGET AUDIENCES: Target audiences for this project were the growers and agribusiness professionals associated with sugarcane. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Brown rust can cause severe epidemics in susceptible sugarcane cultivars during spring and early summer in Louisiana. Therefore, the effect of the disease on yield was evaluated in field experiments conducted during five growing seasons. A combination of three fungicides, azoxystrobin, propiconazole, and tebuconzole, applied bi-weekly during the spring epidemic period kept brown rust severity low (< 5%), and plots receiving repeated fungicide applications provided an estimate of attainable yield for comparison with rust infected plots. Reductions in stalk weight, cane tonnage, and total sucrose yield were associated with brown rust infection. When brown rust severity was only moderate, a similar trend towards lower cane tonnage and total sucrose yield in rust affected plots was evident. Brown rust caused a reduction in cane tonnage of 16-17% and a total sucrose yield reduction of 22% in cultivar LCP 85-384. Comparisons of the yields obtained from plots in which brown rust was controlled early versus late in the epidemic suggested that the impact of the disease is greatest during the late epidemic period when stem elongation has begun.

Publications

• No publications reported this period

Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: The project generated outputs in the form of presentations at grower meetings and regional and international professional society meetings. Abstracts of the professional society meeting have been published and are available to users worldwide. The output information has been used to help growers understand the overall impact of disease on yield. Shifts in management practices have been encouraged. PARTICIPANTS: LSU AgCenter Collaborators: Sugarcane brown rust yield loss: J.W. Hoy, sugarcane pathologist Extension Agents and commercial sugarcane growers. Wheat rust yield loss: G.B. Padgett, agronomy crops pathologist P. Colyer, agronomy crops pathologist S. Harrison, small grains breeder Rice sheath blight yield loss: D.E. Groth, rice pathologist TARGET AUDIENCES: Professional plant pathologists and agronomists, Extension agricultural agents, crop consultants, agribusiness professionals.

Impacts
Yield losses due to brown rust in sugarcane were defined during the 2007 growing year as significant although the brown rust epidemic was described as moderate. Losses of nearly 1300 pounds of sugar per acre were measured in yield loss studies. Variety shifts from highly susceptible to less susceptible have reduced the overall impact to the industry, yet individual susceptible varieties that still have desired cultural advantages are grown. Due to the culture of sugarcane (three- to four-year growing cycles) growers are not able to shift varieties quickly thus resulting in a significant percentage of susceptible germplasm growing in production fields. Fungicide use is being considered with the submission of a Section 18 exemption of FIFRA to the Environmental Protection Agency. Wheat leaf rust yield loss measurements were used in the continued development and refining of a disease management guide and decision aid for growers. Losses during 2007 were less than in the previous five years, so the decision aid proved acceptible but continued refining is necessary. Rice sheath blight yield loss results have continued to aid in better management of the disease for growers. Results are being included in the revision of the rice pathology section of the Rice Production Handbook.

Publications

• Hollier, C.A. and J.W. Hoy. 2007. Yield losses due to brown rust (Puccinia melanocephala) in sugarcane. Proceeding of the XVI International Plant Protection Congress vol.2:808-809. Glasgow, Scotland, UK

Progress 01/01/06 to 12/31/06

Outputs
A study of sugarcane yield loss associated with sugarcane common rust was begun in 2004 and continued in 2005 and 2006. This study used a mixture of fungicides applied at two-week intervals and at varying periods within the rust production timeframe giving protection of some plots early, early to midrange, midrange, midrange to late and late. Data were taken on all yield components of sugarcane. These included stalk counts, stalk height, stalk weight, tons of sugarcane produced per acre, fiber weight and the amount of sugar produced per ton of sugarcane. Stalk counts, stalk height, fiber weights and sugar per ton were not significantly different either year. Stalk weight and tons of sugarcane produced per acre were significantly different among the treatments. From the unsprayed check (the lowest yield) to the highest yielding treatments, the difference was five (5) tons of sugarcane per acre. Sugar per acre produced for those same treatments differed by approximately 2000 pounds per acre in 2004, 994 pounds per acre in 2005 and 1174 pounds in 2006. The test was performed at two locations each year. The study will continue in the spring, summer and fall of 2007. The rice yield loss study began in 2005. This study determined the quantity and quality impacts of the fungal-induced disease, sheath blight. A mixture of fungicides was applied at two week intervals and at varying periods within the sheath blight development stages giving protection of some plots early, early to midrange, midrange, midrange to late and late. Data were taken on all yield components of rice. The first year's data indicate yield difference greater between the healthy and severely blighted rice when sheath blight was evident during the mid to latter rice reproductive stages. Yield losses of 7% were measured representing 476 pounds. Although this difference is significant, greater differences were anticipated. Due to a six week drought during the season, reduced disease development was realized. Wheat yield loss studies began during the 2004-2005 season. Those studies were continued in 2005-2006 and are planted for the 2006-2007 season. As with the above-described studies, a combination of fungicides was used to determine yield losses. Yield loss due to stripe rust development was 7% and test weight was reduced 4%. Leaf rust severity was very low.

Impacts
Overall impact of this study is yet to be determined because of limited data collected. Results of these studies will help producers in making informed disease management decisions.

Publications

• No publications reported this period

Progress 01/01/05 to 12/31/05

Outputs
A study of sugarcane yield loss associated with sugarcane common rust was begun in 2004 and continued in 2005. This study used a mixture of fungicides applied at two week intervals and at varying periods within the rust production timeframe giving protection of some plots early, early to midrange, midrange, midrange to late and late. Data were taken on all yield components of sugarcane. These included stalk counts, stalk height measurements, stalk weight, tons of sugarcane produced per acre, fiber weight and the amount of sugar produced per ton of sugarcane. Stalk counts, stalk height measurements, fiber weights and sugar per ton were not significantly different either year. Stalk weight and tons of sugarcane produced per acre were significantly different among the treatments. From the unsprayed check (the lowest yield) to the highest yielding treatments, the difference was seven (7) tons of sugarcane per acre. Sugar per ton of cane produced for those same treatments differed by approximately 2000 pounds per acre in 2004 and 994 pounds per acre in 2005. The test was performed in two locations each year. The study will continue in the spring, summer and fall of 2006. The rice yield loss study began in 2005. This study was (is) to determine the quantity and quality impacts of the fungal-induced disease, sheath blight. This study used a mixture of fungicides applied at two week intervals and at varying periods within the sheath blight development stages giving protection of some plots early, early to midrange, midrange, midrange to late and late. Data were taken on all yield components of rice. The first year's data indicate yield difference greater between the healthy and severely blighted rice when sheath blight was evident during the mid to latter rice reproductive stages. Yield losses of 8% were measured representing 520 pounds. Although this difference is significant, greater differences were anticipated. Due to a six week drought during the season, reduced disease development was realized. Wheat yield loss studies began during the 2004-2005 season. Yield losses due to stripe rust development were calculated at 7% in the experimental plots. As with the above-described studies a combination of fungicides were used to determine yield losses. Quality losses were also seen reducing the quality, measured as test weight, by 4%. Leaf rust severity was very low.

Impacts
Overall impact of this study is yet to be determined because of limited data collected. The expected impact of these studies will help producers in making informed disease management decisions because they will have more information to use in the decision making process. After the 2006 data are collected, and more certain results are known, the data will be used to give input on impact of these agricultral commodities.

Publications

• No publications reported this period

Progress 01/01/04 to 12/31/04

Outputs
A study of sugarcane yield loss associated with sugarcane common rust was begun in 2004. This study used a mixture of fungicides applied at two week intervals and at varying periods within the rust production timeframe giving protection of some plots early, early to midrange, midrange, midrange to late and late. Data were taken on all yield components of sugarcane. These included stalk counts, stalk height measurements, stalk weight, tons of sugarcane produced per acre, fiber weight and the amount of sugar produced per ton of sugarcane. Stalk counts, stalk height measurements, fiber weights and sugar per ton were not significantly different. Stalk weight and tons of sugarcane produced per acre were significantly different among the treatments. From the unsprayed check (the lowest yield) to the highest yielding treatments, the difference was seven (7) tons of sugarcane per acre. Sugar per ton of cane produced for those same treatments differed by approximately 2000 pounds. The test was performed in two locations. The study will continue in the spring, summer and fall of 2005. Rice and wheat yield loss studies are set to begin this cropping season.

Impacts
Overall impact of this study is yet to be determined because of limited data collected.

Publications

• No publications reported this period