2010 Product Evaluation for Reniform Nematode Suppression

1. 2010 Product Evaluation for Reniform Nematode Suppression in Mississippi Delta Sweetpotato Production Larry C. Adams and Randall G. Luttrell USDA-ARS, SIMRU Stoneville, MS Objective Evaluate five nematicide products for suppression of the reinform nematode species, Rotylenchulusreniformis, in sweetpotatoes, Ipomoea batatas, grown in the Mississippi Delta during the 2010 season. Each product was applied and incorporated into the sweetpotato beds approximately two weeks before transplanting and each treatment was duplicated for three foliar applications of Vydate SL to be applied at fourteen day intervals. Included in this study are yield results of applications of a liquid carbon product, Carbon Boost, and a soil inoculant product, SC 27, applied during transplanting with the nematicide product Nemout. Materials and Methods Research Plot Design Sweetpotato plots were replicated four times with four rows x 25’. Recommended herbicides and nematicide treatments were applied before transplanting. Covington variety sweetpotato slips were transplanted using a two row transplanter at 12” spacing on 5/26/2010. Plots were harvested on 9/15/2010 at 111 days after transplanting. Insect Sampling Sweep Net samples were taken weekly using a 15” sweep net with 100 sweeps at intervals of 25. Insect populations were recorded and treatments applied as needed. Nematicide Treatments Applied on 5/12/10 Untreated Vydate SL @ 128 oz/A 3 weeks before transplanting Telone II @ 6 Gal/A 3 weeks before transplanting K-Pam @ 8 Gal/A 3 weeks before transplanting TRT 1 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervals TRT 2 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervals TRT 3 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervals TRT 4 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervals NemOut@ .6 lbs/A 3 weeks before transplanting with SC27 @ 10 oz NemOut@ .9 lbs/A 3 weeks before transplanting with SC27 @ 10 oz 11) NemOut @ .6 lbs/A 3 weeks before transplanting with Carbon Boost S @ 8 oz/A Carbon Boost S @ 8 oz/A in transplant water Foliar Treatments of VydateSL @ 64 oz/A 6/14/10 6/28/10 7/12/10 Insecticide Treatments Belt @ 3 oz/ A was applied to all plots on 8/05/10 Herbicide Treatments Valor @ 2.5 oz/A was applied pre-plant to all plots on 5/12/10 Command ME @ 2.66 pts/A plus Dual Magnum @ 10 oz/A was applied on 6/8/2010 Select @ 12 oz/A was applied to all plots on 7/02/10 Soil Sample Dates Pre-Transplant – 4/22/2010, Mid-Season – 7/19/2010 & Pre-Harvest – 9/13/2010 Fertilizer 30 units of ammonium nitrate was applied to all plots on 5/7/2010 Irrigation 6/16/2010, 6/25/2010, 7/15/2010 & 8/05/2010 Summary Growing conditions during the 2010 growing season were optimal. Early planting dates and ideal harvest days produced crops with slightly above average yields across the Mid-South. All treatments were irrigated four times and pesticide applications for insect and weed control were applied as needed throughout the season. The reniform nematode samples pulled during mid-season showed that the treatments Telone II, K-Pam, Telone II/Vydate, K-Pam/Vydate,Nemout .6/SC 27 and Nemout .9/SC 27 were maintaining the population under the spring threshold. The pre-harvest samples showed Telone II, Telone II/Vydate and K-Pam/Vydate continued to suppress the reniform nematode throughout the growing season. A significant yield increase of US#1 sweetpotatoes was recorded in the Telone II, K-Pam, Telone II/Vydate, K-Pam/Vydate and Nemout .9/SC 27 treatments when compared to the untreated control (P = 0.0002). Statistically no significant differences were recorded from the US#2 grade and only the K-Pam treatment showed a significant difference in the Jumbo yield (P = 0.1971). The Telone II, K-Pam and Telone II/Vydate treatments showeda significant difference for total marketable yield (P = 0.0157). Although K-Pam/Vydate and Nemout .9/SC 27 treatments yielded very well for total marketable they were not significantly different from the untreated control. The Nemout .6/SC 27, Nemout .6/Carbon Boost and the Carbon Boost treatments were not significantly different from the untreated control. Nematicide Treatments Foliar Vydate Treatment Acknowledgement We thank Chris Johnson, Owen Houston and Phil Powell, USDA, ARS, SIMRU, for their assistance in field plot preparation and maintenance, Dr. Salliana Stetina, USDA, ARS, CGPRU, Pathologist, for processing soil reniform nematode samples and Debbie Boykin, USDA, ARS, Statistician, for assistance with the statistical analysis of the yield data in this study. Untreated Control