Description

Abstract: A 3-year microplOl study was conducted to characterize the interaction between Me/oidogyne arenaria. race 1 (MA I) and M. hapla (MH), as affected by the five peanut genotypes: Florigiant, NC 7, NC 6, NC Ac 18416, and NC Ac 18016. The interactive effects on infection (total parasitic forms per root unit) and reproduction potentials of each nematode species and crop damage were determined. As a single population, MA I had greater infection capacity and caused more crop

damage than did MH, but both species had similar reproduction potentials. In mixed infestations, MA I was more competitive than MH, as reflected by incidence of infection. Infection and reproduction potentials, and crop-damage capabilities of the mixed populations were similar to those of MAl alone. All peanut genotypes were susceptible to infection by both nematodes. NC 6 was less susceptible to damage by MA I and the mixed populations than other genotypes. A nematode treatment x genotype interaction was detected for root infection and crop damage, but not for population density or reproduction. With high preplant nematode levels (Pi), the populations

reached their peak by midseason, whereas those with low Pi peaked after midseason. Crop damage in the second and third years was correlated with Pi level.