Date of Graduation

5-2014

Document Type

Thesis

Degree Name

Master of Science in Plant Pathology (MS)

Degree Level

Graduate

Department

Plant Pathology

Advisor/Mentor

Kirkpatrick, Terrence L.

Committee Member

Slaton, Nathan A.

Second Committee Member

Rothrock, Craig S.

Third Committee Member

Rupe, John C.

Keywords

Cotton; Fertilizer; Fumigation; Nematology; Reniform; Root-knot

Abstract

The use of soil fumigation for nematode management in cotton (Gossypium hirsutum) has become increasingly popular in recent years in the absence of effective resistant cultivars. While soil fumigation is relatively expensive, lint yields have consistently been improved to make this practice profitable in fields with severe nematode pressure. Growers in southern Arkansas have observed changes in cotton growth patterns when severely infested fields are fumigated. The most noticeable change has been excessive (rank) growth resulting in an increased need for growth regulators, especially where the nitrogen fertilization exceeds standard recommendations. Field studies were conducted between 2007 and 2010 to determine if these changes in crop growth are related to nematode control or nitrogen fertilizer rates alone or in combination. Large plot studies were conducted in a field with a history of root-knot nematode (2007) or reniform nematode pressure in (2008 - 2009) consisting of twelve row strips that had received Telone II® (1,3-dichloropropene) paired with equivalent sized strips that received no fumigation. Within these strips five nitrogen rates (34, 101, 123, 146, and 224 kg N/ha) were applied in 30 m long plots. In 2009 and 2010, microplot studies were also conducted in the reniform location. Six row strips that had received Telone II® at 28 l/ha were paired with equivalent sized strips that received no fumigation. Within each strip, three nitrogen rates (0, 101, 146 kg N/ha) were applied in 3 m long plots. Results show yearly variability due to nematicide application and suggest that maintaining fertility is beneficial whether or not nematodes are controlled. Excess growth above normal cotton parameters was not observed due to the inputs.

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