Description

Abstract: A 3-year microplot study was initiated to characterize the population dynamics, reproduction potential, and survivorship of single or mixed populations of Meloidogyne arenaria race I (Mal) and race 2 (Ma2), as affected by crop rotations of peanut ‘Florigiant’ and M. incognita races I and 3-resistant ‘McNair 373’ and susceptible ‘Coker 37 I-Gold’ tobacco. Infection, reproduction, and root damage by Ma2 on peanut and by Malon resistant tobacco were limited in the first year. Infection, reproduction, and root-damage potentials on susceptible tobacco were similar for Ma I and Ma2. In the mixed (1:1) population, Mal was dominant on peanut and Ma2 was dominant on both tobacco cultivars. Crop rotation affected the population dynamics of different nematode races. For years 2 and 3, the low numbers of Mal and Ma2 from a previous-year poor host increased rapidly on suitable hosts. Mal had greater reproduction factors ([RF] = population density at harvest/population density at preplanting) than did Ma2 and Mal + Ma2 in second-year peanut plots following first-year resistant tobacco, and in third-year peanut plots following second-year tobacco. In mixed infestations, Mal predominated over Ma2 in previous-year peanut plots, whereas Ma2 predominated over Ma I in previous-year tobacco plots. Moderate damage on resistant tobacco was induced by Ma I in the second year. In the third year, moderate damage on peanut was associated with ‘Ma2’ from previous-year peanut plots. The resistant tobacco supported sufficient reproduction of Mal over 2 years to effect moderate damage and yield suppression to peanut in year 3. Key words: Arachis hypogaea, interaction, Meloidogyne arenaria, Nicotiana tabarum, parasitic fitness, peanut, population dynamics, reproduction potential, root-knot, rotation, tobacco.