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ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #227363
Title: Cotton Yield Response to Variable Rate Nematicides According to Risk Zones

Author
item ORTIZ, B - UGA
item PERRY, C - UGA
item Sullivan, Dana
item KEMERAIT, B - UGA
item Davis, Richard
item VELLIDIS, G - UGA
item RUCKER, K - UGA

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2008
Publication Date: 9/1/2008
Citation: Ortiz, B.V., Perry, C., Sullivan, D.G., Kemerait, B., Davis, R.F., Vellidis, G., Rucker, K. 2008. Cotton Yield Response to Variable Rate Nematicides According to Risk Zones. ASABE Annual International Meeting. Paper 081026.

Interpretive Summary: Cotton (Gossypium hirsutum L.) lint yield losses by southern root-knot nematode [Meloidogyne incognita] (RKN) have increased during the last 20 years. Site-specific management (SSM) of nematicides is a promising method to reduce yield losses, increase profitability and reduce adverse environmental impacts due to the over-application of agrochemicals. The impact of nematicide type and amount on RKN population density and lint yield were compared across previously determined nematode risk zones in farmer fields during the 2007 growing season. Nematode risk zones consist of areas having a similar soil texture and landscape elevation and were comprised of high, moderate and low risk areas. Within each risk zone treatments were randomly distributed and replicated a minimum of four times in plots (16 rows by 100 feet long). Plot data collected during the growing season consisted of RKN population density, soil water content, plant height, root galling, and final yield. Comparing treatment results across management zones, Telone provided better nematode control compared to Temik in high risk zones, which were comprised of more coarse-textured soil. However, in low risk zones, which were comprised of relatively heavier textured soil compared to the high risk areas, the application of Temik provided sufficient nematicide control. The results from this study clearly showed that nematode control and final yield varied with respect to the nematicide type and rate across management zones (MZ). These results are promising and support the idea of variable rate nematicide applications based on nematode risk zones.

Technical Abstract: Cotton (Gossypium hirsutum L.) lint yield losses by southern root-knot nematode [Meloidogyne incognita] (RKN) have increased during the last 20 years. Site-specific management (SSM) of nematicides is a promising method to reduce yield losses, increase profitability and reduce adverse environmental impacts associated with excess allocations of agrochemicals. The impact of nematicide type and amount on RKN population density and lint yield were compared across previously determined nematode risk zones in farmer fields during the 2007 growing season. Nematode risk zones were delineated in 2006 using fuzzy clustering of elevation and slope of the terrain, normalized difference vegetation index (NDVI) calculated from a bare soil spectral reflectance, and apparent soil electrical conductivity [shallow (ECa-shallow) and deep (ECa-deep)]. Four different treatments of nematicides were randomly allocated among blocks that spanned the entire length of the fields. Test plots (16 rows by 100 feet long) including the four treatments were also randomly selected within each zone to collect RKN population density, soil water content, plant height, root galling, and final yield. In general, there were no benefits associated with a high rate of Telone (6 gal ac-1) versus a lower rate of 3 gal ac-1. Similarly, the higher Temik rate of 6 lbs ac-1 did not provide additional nematicide control compared to the low rate (3 lbs ac-1). Comparing treatment results across management zones, Telone provided better nematode control compared to Temik in high risk zones, comprised of more coarse-textured, sandy soil. However, in low risk zones, which were comprised of relatively heavier textured soil compared to the high risk areas, the application of Temik would provide sufficient nematicide control. The results from this study clearly showed that nematode control and final yield varied with respect to the nematicide type and rate across management zones (MZ). These results are promising and support the idea of variable rate nematicide applications based on nematode risk zones.