Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2007
Publication Date: 11/15/2007
Citation: Abel, C.A., Adams, L.C., Stetina, S.R. 2007. Sweet Potato Yield Reduction Caused by Reniform Nematode in the Mississippi Delta. Plant Health Progress. 10:1094/PHP-2007-1115-01-RS. Interpretive Summary: In 2006, 38,700 ha of sweet potato were grown in the United States. Production of the crop is increasing in the Mississippi Delta, however, very dense populations of the reniform nematode may reduce yields. Three nematicides were applied to experimental plots which reduced reniform nematode numbers by over 2-fold. This reduction in reniform nematodes increasing overall sweet potato yield during each of the three years the research was conducted. The yield increase was the most pronounced for US #1 class sweet potatoes. This benefit is important because the US #1 sweet potatoes typically provide a 7.2-fold and 4.6-fold increase in profit when compared to Canner and Jumbo classes, respectively. This research demonstrated that reniform nematodes reduced total marketable yield and that this yield reduction had the greatest impact on production of the highest value sweet potato, the US #1, in all three years that we conducted the study. The three nematicides we tested were effective in controlling reniform nematodes and in improving sweet potato yield.
Technical Abstract: Very dense populations of the reniform nematode, Rotylenchulus reniformis Linford and Oliveira, can occur in the Mississippi Delta. Sweet potato is a new crop to this area and its production may be affected by high reniform nematode densities. In 2003, post-harvest soil samples revealed that nematicide treated plots had 1019.5' 257.2 reniform nematodes per 473 cm3 sample of soil compared to 2255.0 ' 383.3 for untreated plots. There were 5.3 kg more marketable sweet potato harvested from the nematicide treated plots compared to the control with the treated plots producing 2.6 kg more Canner class and 1.7 kg more US #1 class. In 2004, there were fewer nematodes in the nematicide treated plots and the difference in nematode levels resulted in an 5.0 kg increase in US #1 sweet potatoes. In 2005, two nematicides, K-PAM® and Temik®, were not different in their level of nematode control during the growing season, however, there was an increase in US #1 class sweet potatoes produced from the Temik® treated plots when compared to K-PAM®. Both nematicide treatments produced more US #1 sweet potatoes when compared to a Lorsban® control and an untreated control