2010 Product Evaluation for Reniform Nematode Suppressionin Mississippi Delta Sweetpotato Production

Larry C. Adams and Randall G. LuttrellUSDA-ARS, SIMRU

Stoneville, MS

Objective

Evaluate five nematicide products for suppression of the reinform nematode species, Rotylenchulus reniformis, 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 DesignSweetpotato 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 SamplingSweep 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 5/12/10UntreatedVydate SL @ 128 oz/A 3 weeks before transplantingTelone II @ 6 Gal/A 3 weeks before transplantingK-Pam @ 8 Gal/A 3 weeks before transplantingTRT 1 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervalsTRT 2 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervalsTRT 3 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervalsTRT 4 with 3 foliar applications of Vydate SL @ 64oz./A – 14 day intervalsNemOut @ .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/ACarbon Boost S @ 8 oz/A in transplant water

Foliar Treatments of Vydate SL @ 64 oz/A6/14/106/28/107/12/10 Insecticide TreatmentsBelt @ 3 oz/ A was applied to all plots on 8/05/10

Herbicide TreatmentsValor @ 2.5 oz/A was applied pre-plant to all plots on 5/12/10Command ME @ 2.66 pts/A plus Dual Magnum @ 10 oz/A was applied on 6/8/2010Select @ 12 oz/A was applied to all plots on 7/02/10

Soil Sample DatesPre-Transplant – 4/22/2010, Mid-Season – 7/19/2010 & Pre-Harvest – 9/13/2010 Fertilizer30 units of ammonium nitrate was applied to all plots on 5/7/2010

Irrigation6/16/2010, 6/25/2010, 7/15/2010 & 8/05/2010

2010 Seasonal Reniform Nematode Counts

0250050007500

1000012500150001750020000225002500027500 Untrt

VydateTelone IIK-PamUntrt/VydateVydate/VydateTelone II/VydateK-Pam/VydateNemout .6/SC 27Nemout .9/SC 27Nemout .6/C. BoostC. Boost

# Ren

iform

Nem

atod

es/P

int o

f Soi

l

Larry AdamsUSDA-ARS, SIMRUStoneville, MS

Mid SeasonCount

Pre-HarvestCount

Fall Threshold – 5000/Pint Spring Threshold – 2000/Pint

2010 Reniform Nematode Study Yield

0

100

200

300

400

500

600 UntrtVydateTelone IIK-PamUntrt/VydateVydate/VydateTelone II/VydateK-Pam/VydateNemout .6/SC 27Nemout .9/SC 27Nemout .6/C. BoostC. Boost

Larry AdamsUSDA-ARS, SIMRUStoneville, MS

US#1 50 Lb. Bushels/Acre

331*ef

510a

418bc

379cdef

375cdef

479ab

409bcd

370cdef

422bc 405

bcde

335def

* Means Followed By The Same Letter Are Not Significantly Different

327f

2010 Reniform Nematode Study Yield

0

20

40

60

80

100

120

US#2 Jumbo

UntrtVydateTelone IIK-PamUntrt/VydateVydate/VydateTelone II/VydateK-Pam/VydateNemout .6/SC 27Nemout .9/SC 27Nemout .6/C. BoostC. Boost

Larry AdamsUSDA-ARS,SIMRUStoneville, MS

CWT

No Significant Difference K-Pam Treatment Significantly Different

2010 Reniform Nematode Study Yield

05000

1000015000200002500030000350004000045000 Untrt

VydateTelone IIK-PamUntrt/VydateVydate/VydateTelone II/VydateK-Pam/VydateNemout .6/SC 27Nemout .9/SC 27Nemout .6/C. BoostC. Boost

Larry AdamsUSDA-ARS, SIMRUStoneville, MS

Lbs. Total Yield/Acre

* Means Followed By The Same Letter Are Not Significantly Different

c* c

aba

bcbc

ab

abc

bc

abc

c c

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 showed a 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.

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.

NematicideTreatments

Foliar VydateTreatment

UntreatedControl