Morphological Comparison of Meloidogyne Males by Scanning Electron Microscopy


  • W. A. Rohde
  • A. W. Johnson
  • C. C. Dowlet
  • N. C. Glaze


Field plots of Tifton loamy sand were treated with methyl bromide, DD-MENCS, or ethoprop for control of root-knot nematodes, Meloidogyne incognita, in a multiple cropping system of turnips, field corn, and southern peas. Annual applications of methyl bromide and DD-MENCS in November or December suppressed nematode numbers to very low levels through September, but numbers increased in the following October, November, and/or December. No benefit was found from ethoprop applied to DD-MENCS-treated plots before the planting of each crop. Nematode numbers were not significantly suppressed by ethoprop alone. Concentrations of ethoprop in the 0-15-cm soil layer were near 6 [mu]g/g at application but were 1[mu]g/g of soil 5 days later on corn and southern peas and 30 days later on turnips. Ethoprop concentrations of 4.6 to 5.6 [mu]g/g of soil are too low for adequate control of root-knot nematodes on field corn and southern peas in multiple cropping systems. Stepwise regression analyses indicated that 81% and 36% of the variations in concentration of ethoprop in the soil were attributable to the amount of water that the plots received when the maximum soil temperature ranged from 10 C to 19 C and from 31 C to 41 C, respectively, and that 11% was attributable to the maximum soil temperature within the temperature range of 17 C to 33 C. Key Words: Nematode control, dissipation of ethoprop, multiple-cropping, Meloidogyne incognita.