Influence of Glomus fasciculatum and Meloidogyne hapla on Allium cepa in Organic Soils

摘要

The influence of Meloidogyne hapla and Glomus fasciculatum on Allium cepa (onion) grown in organic soil was evaluated under greenhouse conditions. In the absence of G. fasciculatum, M. hapla significantly retarded the growth of A. cepa cv. Krummery Special and MSU 8155 × 826, but had no detrimental influence on Downing Yellow Globe, Spartan Banner, or Spartan Sleeper. All five cultivars maintained populations of M. hapla, Final root population densities of M. hapla associated with Spartan Banner, Krummery Special, MSU 8155 × 826, and Spartan Sleeper were significantly greater than those recovered from Downing Yellow Globe. Final root population densities of M. hapla were directly proportional to the initial population densities. Root colonization of onion by G. fasciculatum significantly enhanced the growth and development of Downing Yellow Globe. The rate of increase of A. cepa growth and the final spore density were directly proportional to the initial spore density of G. fasciculatum. Final population densities of M. hapla in the presence of G. fasciculatum were generally greater than in the absence of the fungus. After 15 weeks, A. cepa plants grown in the presence of both M. hapla and G. fasciculatum were significantly larger than those grown in the presence of only M. hapla.