Sweet Potato Yield Reduction Caused by Reniform Nematode in the Mississippi Delta

Abstract

A study was conducted to determine the effect of variable reniform nematode, Rotylenchulus reniformis Linford and Oliveira, population densities on sweet potato production. In 2003, post-harvest soil samples revealed that nematicide-treated plots had 1019 ± 257.2 reniform nematodes per 500 cm3 sample of soil compared to 2255 ± 383.3 for untreated plots. There were 1057 kg/ha more marketable sweet potato harvested from the nematicide-treated plots compared to the control. In 2004, there were fewer nematodes in the nematicide-treated plots at pre-planting, mid-season, and pre-harvest, with the most pronounced difference occurring at mid-season with 927 nematodes per 500 cm3 sample of soil in the nematicide untreated plots compared to 140 for the treated plots. The difference in nematode levels resulted in a 996-kg/ha increase in US #1 sweet potatoes harvested from nematicide-treated plots compared to the untreated plots. 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. Accepted for publication 13 September 2007. Published 15 November 2007.