Research indicates that cotton yield on light soils within the alluvial flood plain of the Lower Mississippi delta may be increased by using chemical fumigation applications of Telone II and/or seed treatments to control infestations of plant parasitic nematodes. There is a documented interaction with fumigation and nitrogen and therefore a need to further understand the performance of site- specific treatment strategies for nitrogen (N) and fumigation treatments. In a small plot test conducted at the Northeast Research Station on Commerce silt loam soil, thrips population resurgence was significantly higher in plots treated with Avicta Complete PAK (ACP) Plus 120 lb N as compared to the non-treated plots Plus 120 lb N at 33 days after planting. Plant stand was significantly lower in the non- treated, and node of 1st square was significantly increased in plots treated with Telone II plus 80 lb N. GPS point data was interpolated using Inverse Distance Weighting (IDW) which made root mean square (RMS) values available as additional measures of yield variation. Root-knot nematode counts extracted from soil samples taken in June revealed that the highest level of control was with the Telone II fumigation treatment. Nematode populations were clumped and variable regardless of treatment and populations were higher in the non-treated. The high N strategy of 120 lb N plus ACP seed treatment out yielded Telone II plus ACP plus the low N strategy of 80 lb N. Yields were significantly better in both nematicide treatments as compared to the non-treated plus high N strategy. When treatment polygons were merged into a single field, histogram analysis indicated

yield ranged from 1029 – 1808 lbs lint. Yield for 74 of 96 data points was 1500 lbs or greater. When the yield features were linked in Arc GIS 9.1, it was observed that high yields corresponded to nematode treatments and low yields corresponded to the non-treated. RMS values were 61.3, 56.6 and 215.6 respectively, for the treatments.

In 2007 an embedded field trial was conducted on a 33 acre field consisting of Dundee silt loam and transitioning to Tensas clay, for the purpose of developing a variable- rate treatment prescription for that farm. Test treatments included three Nitrogen rates (80, 115, 135 lb actual N) applied with and without Telone II. The entire test area was treated with Avicta Complete PAK. Histogram analysis for the 39 acre test field indicated yield ranged from 480 – 1808 lb lint per acre, with an average for the field of 1316 lbs of lint per acre. Moran’s I index was found to be 0.05 and Z score = 169.5 standard deviations, indicating significant spatial autocorrelation. After consolidation and processing of the data by the GIS specialist, the data were sent to the Department of Experimental Statistics at LSU for analysis. Linear mixed models analysis of covariance incorporating spatial components was used to analyze the data and make treatment comparisons within the various field management zones defined by ECa zone, drainage area zone, nematode density zone, and elevation. The statistical models were developed using SAS® software. Once this was done, open source software developed by LSU’s Department of Experimental Statistics was used to apply several potential producer preferences to the results of the statistical analysis, resulting in multiple prescription options suitable for site-specific treatments of Telone II and/or selected nitrogen (N) strategies. The treatment prescriptions were provided to the researchers and agricultural producer in graphical format for visual inspection, and in .csv file format for importing into variable-rate application equipment.