Tuesday, September 11, 2007

Comparison of Early and Normal Planting Dates for Suppression of Reniform Nematode Populations

Dr. Salliana R. Stetina1, Dr. Gabriel L. Sciumbato2, Dr. William T. Pettigrew1, and Dr. William T. Molin3. (1) USDA ARS Crop Genetics and Production Research Unit, PO Box 345, Stoneville, MS 38776, (2) Mississippi State University Delta Resarch and Extension Center, PO Box 197, Stoneville, MS 38776, (3) USDA ARS Southern Weed Science Research Unit, PO Box 350, Stoneville, MS 38776

The reniform nematode (Rotylenchulus reniformis Linford & Oliveira) causes significant yield losses in cotton (Gossypium hirsutum L.) in the southeastern United States. In this region, management relies primarily on the use of nematicides, which are expensive and often give inconsistent results. Alternative management options are needed to limit losses. The objective of this research was to determine if nematode population suppression and associated yield benefits would result from planting cotton a month earlier than normal, when cooler soil temperatures limit nematode activity.  Early (April 1) and normal (May 1) planted cotton plots were established in fields naturally infested with reniform nematode. At 5 weeks after planting (three trials) and at the end of the season (four additional trials), reniform nematode populations in plots planted early did not differ significantly from those in plots planted at the normal time. In only one trial did cotton planted early yield higher than cotton planted at the normal time. The yield benefits derived from early planting, when present, do not result from a reduction in the reniform nematode population.