Control of Tobacco Black Shank with Combinations of Systemic Fungicides and Nematicides or Fumigants. A. S. Csinos, Plant Pathologist, University of Georgia, Coastal Plain Experiment Station, USDA, ARS, Tifton, GA 31793. N. A. Minton, Research Nematologist, USDA, ARS, Tifton, GA 31793. Plant Dis. 67:204-207. Accepted for publication 18 June 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/PD-67-204.

In 1979, field plots were established in an area heavily infested with Phytophthora parasitica var. nicotianae and lightly infested with Meloidogyne incognita to compare fungi-specific systemic fungicides alone and with fumigant and nonfumigant nematicides/insecticides applied by several methods for control of tobacco black shank. Metalaxyl at 2.24 kg a.i./ha preplant incorporated reduced black shank when used alone or with a fumigant or nonfumigant nematicide, although disease control was greater when combinations were used. Regardless of the nematicide used, propamocarb, RE26940, or RE26745 did not decrease disease severity or increase yield compared with the control. Phenamiphos in 1979 and ethoprop-disulfoton in 1981 increased yield over the control and ethoprop in 1981 decreased disease index. Yields of plants in plots treated with EDB-C30 and EDB-C45 in 1979 and 1980 were greater than yields from untreated controls. Root-gall evaluations and numbers of M. incognita juveniles in the soil were erratic and differences among treatments were not significant (P = 0.05). Data indicated that metalaxyl tank mixed with nonfumigant nematicides or used in combination with fumigants or granular nematicides had no adverse effect on plant growth and increased disease control and yield.

Keyword(s): oomycete-specific fungicides, root-knot nematodes.