Robert Carver, Overstreet, Charles
INVESTIGATOR: Overstreet, C.
Plant Pathology & Crop Physiol
LOUISIANA STATE UNIVERSITY
BATON ROUGE, LOUISIANA 70893
SITE-SPECIFIC MANAGEMENT OF SOUTHERN ROOT-KNOT AND RENIFORM NEMATODES IN COTTON
CLASSIFICATION HEADINGS: R212 . Pathogens and Nematodes Affecting Plants; S1710 . Upland cotton; F1120 . Nematology
NON-TECHNICAL SUMMARY: Plant-parasitic nematodes are major pests of cotton in the United States. Nematicides are currently one of the primary methods used to manage these pests. Although nematodes such as the Southern root-knot and reniform may be fairly widespread in cotton fields, there are often areas in many fields that would require different nematicide treatments. The rationale for this project is to be able to define these different areas in a field and apply the correct nematicide. Soil texture may play an important role in defining which areas of a field need treating. This project will also look at some of factors that might change the damage caused by nematodes and the areas of a field that would require treatment. These factors include the impact of rotations with another widely grown crop such as corn, nematicide types, and fertility levels across changing soil types. The results of this project should help producers better understand management of nematodes and correctly apply nematicides in an environmentally sound and effective manner.
OBJECTIVES: 1. Development of site-specific management strategies for Southern root-knot and reniform nematodes. 2. Evaluation of interfield factors that influence reniform or Southern root-knot nematode populations and impact on nematode management zones. Nematode management has changed drastically in cotton during the past decade due to the advent of seed treatment nematicides and current rotations with more economically viable crops such as corn. Because seed-treatment nematicides are only effective in fields with low populations of problem nematodes, additional treatments may be needed when nematode populations are at damaging populations. This research is aimed at better defining the areas of a field that may need this supplemental treatment with an additional nematicide. Since corn is a major rotation crop with cotton, it will impact population development of both the Southern root-knot and reniform nematodes. One- or two-year rotations with corn in fields with varying levels of soil texture should help with the understanding of population development of the nematodes in each of the different soil types. Management zones for nematodes can be adjusted with a greater understanding of the impact of this rotation. The use of seed-treatment nematicides and soil fumigant (Telone) will be evaluated in nematode-infested soils with varying levels of soil texture. This will help determine when to use different nematicides or combinations in soils that have textural changes within the same field. Soil fertility may have an impact on nematode damage and especially in different soil types. Management zones may be influenced by these interfield factors and change over time. Producers will benefit from this type of information for development of cost-effective methods of nematode management.
APPROACH: Objective 1. A series of four to six verification strips (12-24 rows wide) will be treated with Telone in a production field naturally infested with one of the major nematodes. The strips will be spaced so that the treated rows will maximize the soil textural differences within the field. The soil texture differences will be determined prior to planting using apparent electrical conductivity (EC) and will measured by the use of a Veris 3100 Soil EC Mapping System. Each field will have 4-7 soil types based upon EC. Nematode densities will be established at planting and again at harvest. Yield data will be collected using a yield monitor. The yield of the Telone strips in each of the soil types will be compared with untreated rows in the same soil type. The information about nematicide response, nematode densities, and soil texture will be used to develop management-zone strategies. Objective 2. Population development of nematodes, efficacy of nematicides, and fertility are several factors that may influence management zones. Several production fields will be monitored for the impact of rotation with corn and cotton on populations of either Southern root-knot or reniform nematodes across soil texture zones. The fields will be measured for soil texture using EC and divided into a series of 4-7 soil types. A series of sampling sites (4-6) will be established in each of the soil zones and monitored for population changes over time with corn grown in rotation with cotton for 1 or 2 years. The sampling sites will be geo-referenced and sampled for nematodes in the spring and fall. The results of the nematode sampling should provide information about population development in different soil zones and how it would impact the development of management zones. Nematicide trials will be conducted in nematode-infested cotton fields with varying soil texture to determine the efficacy of Telone, Avicta Complete Cotton, or combinations. The field will be mapped for EC, and a series of whole plots (6-8) will be based on soil texture. Each of the nematicide treatments will be replicated 4 times in each these whole plots. Nematode samples will be collected at planting and again at harvest. Yield, nematode populations, and soil texture will be used to determine the best nematicides for fields with varying soil types. Fertility studies will also be conducted in a field with natural infestation of Southern root-knot or reniform nematodes to determine how this might impact management zone designation. A low/high fertility regime will be established in a field with varying soil texture. The field will be measured for EC and divided into whole plots similar to the nematicide study. Each of the fertility regimes will be treated with and without Telone. The impact of fertility and nematicides will be determined across a range of soil textures.
KEYWORDS: nematodes; site specific; crop damage; equipment; management; populations; reniform nematode; rootknot nematode; soil texture; fertility; nematicides; rotation; management zones; electrical conductivity
PROGRESS: 2010/01 TO 2010/12
OUTPUTS: There were seven outputs. There were two presentations at professional conferences, the Society of Nematologist and 3rd Conference on Precision Crop Protection. Information about this project was also presented to producers and industry members at field days held at the Northeast Research Station in Louisiana and Milan No-Till Crop Production field day in Tennessee. A fact sheet was also developed for producers on sampling strategies for plant-parasitic nematodes incorporating apparent electrical conductivity for zone development. PARTICIPANTS: Dr. Roberto Barbosa, Department of Biological & Agricultural Engineering, assisted in research of this project. Dennis Burns and Ralph Frazier, county agents, assisted in the research and outreach components of this project. Deborah Xavier and Manjula Kularathna, graduate assistants, helped with the research projects. TARGET AUDIENCES: Target audiences for this project include other scientists, crop producers, consultants, county agents, and industry members. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
IMPACT: 2010/01 TO 2010/12
The use of apparent electrical conductivity (ECa) is being evaluated as a method of developing management zones for plant-parasitic nematodes in cotton. Damage and incidence of the Southern root-knot nematode decreases as soil texture changes from the coarse-textured soils to fine-textured soils. Reniform nematode causes damage and incidence over a broader range of soil textures extending from coarse to fine-textured soils. These differences in soil textures can be successfully identified using ECa as measured by the Veris Soil EC Mapping Systems. Production fields of cotton can be divided into soil management zones based on ECa that relates to incidence and damage potential of either Southern root-knot or reniform nematodes. Nematicide selection and application for each management zone will depend upon damage potential of either nematode species. Outcome is that there will be considerable savings in chemical costs and increased profitability with proper applications of nematicides.
PUBLICATIONS (not previously reported): 2010/01 TO 2010/12
1. Muller, J. D., T. L. Kirkpatrick, C. Overstreet, R. F. Davis, W. S. Monfort, A. Khalilian, W. G. Henderson, Jr. 2010. Nematode management zones based on soil texture. Page 138 in Proc. 3rd Conference on Precision Crop Protection. Bonn, Germany.
2. Overstreet, C. 2010. Looking at better ways to managing nematodes in cotton. Page 15 to 17 in Proc. Thirteenth Annual National Conservation Systems Cotton & Rice Conference. Alexandria, LA.
3. Overstreet, C., E. C. McGawley, M. Wolcott, D. Burns, E. Burris, and G. B. Padgett. 2010. Using verification strips to define nematicide response areas to the Southern root-knot and reniform nematodes in cotton in the Alluvial soils of the mid-South, USA. Page 144 in Proc. 3rd Conference on Precision Crop Protection. Bonn, Germany.
4. Overstreet, C., E.C. McGawley, C. Hollier, D. Ferrin, and R. Singh. 2010. Strategies for sampling plant-parasitic nematodes in field crops. LSU AgCenter Pub. 3143, 4 pages.
Name: Overstreet, C.