Author
ORTIZ, BRENDA - Auburn University | |
PERRY, CALVIN - University Of Georgia | |
SULLIVAN, DANA - Turf Scout,llc | |
LU, PING - University Of Georgia | |
KEMERAIT, ROBERT - University Of Georgia | |
Davis, Richard | |
SMITH, AMANDA - University Of Georgia | |
VELLIDIS, GEORGE - University Of Georgia | |
NICHOLS, ROBERT - Cotton, Inc |
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/3/2012 Publication Date: 6/18/2012 Citation: Ortiz, B.V., Perry, C., Sullivan, D., Lu, P., Kemerait, R., Davis, R.F., Smith, A., Vellidis, G., Nichols, R. 2012. Variable rate application of nematicides on cotton fields: A promising site-specific management strategy. Journal of Nematology. 44(1):31-39. Interpretive Summary: Field tests were conducted to determine if differences in response to nematicide application (i.e., root-knot nematode (RKN) population levels, cotton yield, and profitability) occurred among RKN management zones (MZ). The MZ were delineated using variables related to soil texture, including apparent soil electrical conductivity, elevation, slope, and changes in bare soil reflectance. Zones with coarser soil textures were designated as having greater risk for high RKN levels. Nematicide-treated plots were established within each zone, and the nematicides (aldicarb [Temik] and 1,3-dichloropropene [Telone II]) were applied at two rates (3.4 and 6.7 kg/ha for Temik, and 28 and 56 liter/ha for Telone II) to RKN MZ in commercial fields between 2007 and 2009. Analysis of RKN population levels showed that regardless of the zone there were no differences between Temik rates or between Telone II rates. Telone II provided better RKN control than did Temik in zones with more coarse-textured, sandy soil. In contrast, in low risk zones with relatively heavier textured soil compared to the high risk areas, the effects of Telone II and Temik were equal and application of any of the treatments provided sufficient control. In low RKN risk zones, a farmer would often have lost money if a high rate of Telone II was applied. This study showed that the effect of nematicide type and rate on RKN control and cotton yield varied across management zones (MZ) with the most expensive treatment likely to provide economic benefit only in zones with coarser soil texture. This study demonstrates the value of site specific application of nematicides based on management zones, although this approach will likely have the greatest benefit in fields with the greatest variability in soil texture. Technical Abstract: Field tests were conducted to determine if differences in response to nematicide application (i.e., root-knot nematode (RKN) population levels, cotton yield, and profitability) occurred among RKN management zones (MZ). The MZ were delineated using variables related to soil texture, including apparent soil electrical conductivity, elevation, slope, and changes in bare soil reflectance. Zones with coarser soil textures were designated as having greater risk for high RKN levels. Nematicide-treated plots (4 rows wide and 30 m long) were established in a randomized complete block design within each zone. The nematicides (aldicarb [Temik] and 1,3-dichloropropene [Telone II]) were applied at two rates (3.4 and 6.7 kg/ha for Temik, and 28 and 56 liter/ha for Telone II) to RKN MZ in commercial fields between 2007 and 2009. A consolidated analysis of RKN population levels by treatment within zones showed that regardless of the zone there were no differences between Temik rates or between Telone II rates. The result across zones showed that Telone II provided better RKN control than did Temik in zones with more coarse-textured, sandy soil. In contrast, in low risk zones with relatively heavier textured soil compared to the high risk areas, the effects of Telone II and Temik were equal and application of any of the treatments provided sufficient control. In low RKN risk zones, a farmer would often have lost money if a high rate of Telone II was applied. This study showed that the effect of nematicide type and rate on RKN control and cotton yield varied across management zones (MZ) with the most expensive treatment likely to provide economic benefit only in zones with coarser soil texture. This study demonstrates the value of site specific application of nematicides based on management zones, although this approach will likely have the greatest benefit in fields with the greatest variability in soil texture. |