ARS | Publication request: On-Going Performance of Vineyard Replant Trials Initiated in 1998-2000.

Submitted to: Proceedings of Methyl Bromide Alternatives Conference
Publication Type: Proceedings/Symposium
Publication Acceptance Date: November 6, 2001
Publication Date: November 6, 2001
Citation: SCHNEIDER, S.M., AJWA, H.A., TROUT, T.J., BROWNE, G.T., SIMS, J. ON-GOING PERFORMANCE OF VINEYARD REPLANT TRIALS INITIATED IN 1998-2000.. PROCEEDINGS OF METHYL BROMIDE ALTERNATIVES CONFERENCE. 2002.

Interpretive Summary: "Replant disorder" is a general term for the lack of vigor in a newly replanted vineyard as compared to vines planted in "non-vineyard" soil. Fumigation with methyl bromide prior to replanting can alleviate the problem, but the on-going methyl bromide phase-out is impacting cost and availability of this control strategy. Field trials to evaluate potential alternatives for perennial crops must determine efficacy of pathogen control not only at the time of planting the new vineyard, but must assess the on-going performance of the methyl bromide alternatives during the early growth and fruiting years. Three years after treatment and re-planting of a 65-year old vineyard infested with plant parasitic nematode populations, drip-applied 1,3-D and shank-applied iodomethane continue to give control of the rootknot and citrus nematode populations that is equivalent to that obtained with methyl bromide. The Harmony rootstock continues to support only minimal populations of the rootknot nematode, even in the untreated plots, but supports higher populations of the citrus nematode than either Thompson Seedless or Teleki 5C. Iodomethane and the 1,3-D appear to be good alternatives to methyl bromide for vineyard replant when both rootknot and citrus nematode are present, at least for the first 3 years after establishment of a replanted vineyard. If only rootknot nematode is present, the Harmony rootstock is a good alternative - alone or in combination with chemical controls, but citrus nematode populations will increase on Harmony if it is used without any chemical control.

Technical Abstract: "Replant disorder" is a general term for the lack of vigor in a newly replanted vineyard as compared to vines planted in "non-vineyard" soil. Fumigation with methyl bromide prior to replanting can alleviate the problem, but the methyl bromide phase-out is impacting cost and availability of this control strategy. Field trials to evaluate potential alternatives for perennial crops must determine efficacy of pathogen control not only at the time of planting the new vineyard, but must assess the on-going performance of the methyl bromide alternatives during the early growth and fruiting years. Three years after treatment, nematode control in plots treated with drip-applied 1,3-D and shank-injected iodomethane is comparable to plots treated with methyl bromide for all grape cultivar/rootstock combinations tested. Nematode populations in the one-year fallow and fallow+cover crop treatments were not different from the untreated control. The Harmony rootstock supported lower populations of the rootknot nematode, but higher populations of the citrus nematode than the other rootstocks. Vine growth was greatest in the chemical treatments. Yield of Thompson Seedless grapes was greatest in the chemical treatments. The shank-injected iodomethane and drip-applied 1,3-D appear to be promising alternatives to methyl bromide for vineyard replant up to 3 years after treatment.