Evaluation of variable rate nematicide applications using precision farming methods to manage Meloidogyne incognita on cotton

R. E. Baird, J. R. Rich, D. Waters


Three field trials were conducted on a farm in southwest Georgia, U.S.A., comparing standard single rate to variable rate applications of 1,3-dichloroproprene O,3-D) and aldicarb on the growth of cotton and soil population densities of Me!oidogyne incognita. A 40 ha field was subdivided into 0.4 ha grid areas by using a global positioning system (GPS). Soil samples for nematode analyses were obtained from each grid area, and maps depicting the range of M. incognita second stage juvenile (2) population densities were created. Variable rates of l,3-D and aldicarb were applied using prototype equipment designed to enable site specific applications based on nematode densities which varied among the field plots. During the two growing seasons, plant stands and M. incognita J2 population densities generally did not differ among the treatments. The variable rate aldicarb applications did not show yield or economic advantages over the use of standard single rate applications of this nematicide. Variable rate applications of 1,3-D, however, produced either similar or significantly greater yields than the single uniform rate applications. The cost of soil sampling and analysis needed with variable rate application of 1,3-D was offset by the savings obtained from reduced total chemical usage in both years. The lower chemical input costs and environmental benefits of variable rate l,3-D application can be recommended for M. incognita control on Georgia cotton farms.

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