Author
Davis, Richard | |
KOENNING, S - NC STATE UNIVERSITY | |
KEMERAIT, R - UNIVERSITY OF GEORGIA | |
CUMMINGS, T - COOP EXTN SERVICE |
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/27/2002 Publication Date: 3/1/2003 Citation: Davis, R.F., Koenning, S.R., Kemerait, R.C., Cummings, T.D. 2003. Rotylenchulus reniformis management in cotton with crop rotation. Journal of Nematology. 35(1):58-64. Interpretive Summary: The reniform nematode, Rotylenchulus reniformis, is found throughout the southern United States and has a wide host range that includes cotton and many vegetable and field crops. Highly infested fields are found in cotton fields from Georgia to Texas, and yield losses can be 30-40%. Management options are limited to increased use of current rotation crops, new applications of underutilized rotation crops, and nematicides. The use of crop rotation with resistant host plants for reniform nematode management has received relatively little attention. Our objective was to compare the effects of reniform-resistant soybean and corn on nematode population densities and subsequent cotton yield when grown in rotation with cotton. Continuous cotton with various nematicide regimes also was evaluated. One-year rotations to corn or resistant soybean resulted in statistically lower nematode levels than those found in cotton at three out of four test sites, and levels were numerically lower at the fourth location. However, the effect of rotation on nematode populations was undetectable by mid-season when cotton was grown the following year. Cotton yield following a one-year rotation to resistant soybean increased numerically at all test locations compared to continuous cotton, and yield following corn increased numerically in three locations. The optimum application rate for aldicarb, the nematicide tested in this study, was found to be lower than the rate often used by farmers. Supplemental applications of the nematicide made 30-40 days after planting resulted in yield increases insufficient to re-coup the cost of application in three of the four years. Technical Abstract: One-year crop rotations with corn or highly resistant soybean were evaluated at four locations for their effect on Rotylenchulus reniformis population levels and yield of a subsequent cotton crop. Four nematicide (aldicarb) regimes were included at two of the locations, and rotation with reniform-susceptible soybean was included at the other two locations. One-year rotations to corn or resistant soybean resulted in lower R. reniformis population levels than those found in cotton at three test sites, and levels were numerically lower at the fourth location. However, the effect of rotation on nematode populations was undetectable by mid-season when cotton was grown the following year. Cotton yield following a one-year rotation to resistant soybean increased numerically at all test locations compared to continuous cotton, and yield following corn increased numerically in three locations. The optimum application rate for aldicarb in this study was 0.84 kg a.i./ha in-furrow. Side-dress applications of aldicarb resulted in yield increases insufficient to re-coup the cost of application in three of the four years. |