Crop Loss Assessment (Plant Disease Losses)

ACCESSION NO: 0199362 SUBFILE: CRIS
PROJ NO: LAB93680 AGENCY: CSREES LA.B
PROJ TYPE: HATCH PROJ STATUS: NEW
START: 01 OCT 2003 TERM: 30 SEP 2008 FY: 2004

INVESTIGATOR: Hollier, C. A.

PERFORMING INSTITUTION:
Plant Pathology & Crop Physiology
Louisiana State University
Baton Rouge, Louisiana 70803

NON-TECHNICAL SUMMARY: Plant diseases cause yield losses in field crops. This project will determine the yield loss associated with sheath blight of rice, common rust of sugarcane and leaf rust of wheat.

OBJECTIVES: The objectives of this project are: (1) to determine the potential yield loss due to common rust in sugarcane, (2) to determine yield losses due to leaf rust of wheat and (3) to determine the impact of sheath blight of rice on yield.

APPROACH: The first sugarcane yield loss measurement technique to be used sugarcane is the single plant method in which plants are identified and marked for evaluation. Disease is assessed once on a large number of individual plants with a variety of disease severities. Yield is determined at maturity, collected and grouped by disease levels to obtain a mean yield for that group. General data collected will include: current and past cropping history and disease history. Yield components will be measured. Disease ratings will be expressed as a percentage of leaf area covered for the whole plant. Another technique is the use of conventional replicated field experiments in which fungicides are used to prevent, delay or stop epidemics. The test will be conducted in commercial fields where common rust is found because of natural infection. The test will be a randomized complete block design replicated four times. Each plot will be three rows X 25 feet. The applications will delay epidemics at various intervals to provide information on the effect of the initiation of epidemics at certain crop development stages. Disease development data are taken at intervals during the study to calculate disease progress. Standard yield and quality information will be taken at harvest. Another technique is the use of surveys to be accomplished in many commercial fields. The surveys will be done using GPS-equipped handheld computers, on which information about location (latitude, longitude), field characteristics and disease information will be recorded. Once the yield loss information is collected and has been analyzed, an economic analysis will be done. The wheat leaf rust study will be conducted at three locations: the Ben Hur facility, the Dean Lee Research Station and the Macon Ridge Station. All plots will be set up identically at each location, with three varieties replicated four times. Border rows will be included to remove interplot interference. The plots will be seven drill rows X 25 feet in a randomized complete block design. The yield loss techniques to be used will be the same as those used in the sugarcane study. Likewise, the information concerning the field and cropping history will be collected. The wheat leaf rust yield loss studies will be conducted by collecting mature heads and evaluating yield components. Small plot tests will be harvested with a small plot combine and large commercial fields will be harvested with commercial harvesting equipment. The disease rating will be expressed as the leaf area covered of the flag and flag-1 leaves of each plant. Sheath blight yield loss studies will be conducted at the Rice Research Station. The yield loss techniques described above will be used for this research, too. For on-station replicated plots, two varieties will be planted and inoculated with R. solani. Fungicide applications to alter the expression of epidemics will be applied in a randomized complete block design with four replications. Plot size will be seven drill rows X 25 feet. Disease ratings will be taken at periodic growth stages during the crop year to determine sheath blight development. Quantity and quality measurements of yield will be determined.

PROGRESS: 2004/01 TO 2004/12
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 mid-range, mid-range, mid-range 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 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.

IMPACT: 2004/01 TO 2004/12
Overall impact of this study is yet to be determined because of limited data collected.

PUBLICATIONS: 2004/01 TO 2004/12
No publications reported this period

PROJECT CONTACT:
Name: Boethel, D. J.
Phone: 225-578-4182
Fax: 225-578-4225
E-mail: dboethel@agcenter.lsu.edu  

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