Integrating Matriconditioning and Fungicidal Treatment of Table Beet Seed to Improve Stand Establishment and Yield
- Anwar A. Khan ,
- George S. Abawi and
- James D. Maguire
Preplant conditioning with solid carriers, termed matriconditioning, has proved effective in improving early emergence of vegetable seeds in laboratory studies. The objective of this study was to combine the advantages of matriconditioning with effective fungicide treatments to further improve emergence and yield in table beet (Beta vulgaris L. cv. Ruby Queen). Of the various carriers used, Micro-Cel E (a synthetic calcium silicate) was found to be more effective than expanded vermiculite or Agro-Lig (a Leonardite shale). The conditioning mixture consisted of 1 part seed to 0.2 part Micro-Cel E to 1.15 part water (or fungicide suspension) by weight. Seeds were conditioned for 7 d at 15 °C. Although washing after conditioning improved the early emergence, air-drying of conditioned seeds, with or without washing, was essential for obtaining maximum stand. A combined treatment of conditioning and metalaxyl [(N-(2,6-dimethylphenyl)-N-(methoxyacetyl) alanine methyl ester] + tolclofos-methyl (O-2,6-dichloro-4-methylphenyl O,O-dimethyl phosphorothioate) was more effective than the conditioning or fungicide seed treatment alone in improving stand and in reducing seedling mortality at 22 to 25 °C in soil infested with soilborne pathogen, Rhizoctonia solani Kuhn. In noninfested soil, conditioning with metalaxyl + thiram (tetramethylthiuram disulfide) was most effective. At 15 °C, conditioning in combination with metalaxyl + tolclofos-methyl or metalaxyl + thiram induced earlier emergence and produced larger stands than did conditioning or fungicide treatment alone. In a filed trial planted on 1 May 1990, conditioning combined with metalaxyl + tolclofos-methyl or metalaxyl + thiram produced a larger stand than did conditioning or fungicide treatment alone. In a field trial planted on 21 June 1990 and artificially infested with mycelial suspensions of R. solani and Pythium ultimum Trow, conditioning combined with metalaxyl + tolclofos-methyl or metalaxyl + thiram reduced the early emergence time and increased the marketable root yield over that of conditioning or fungicide treatment alone. Root disease incidence was reduced maximally when conditioning was combined with metalaxyl + tolclofos-methyl, to a lesser extent by fungicides alone, and none by conditioning alone.
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