Effect of Glomus fasciculatum on the Growth of Asparagus and the Incidence of Fusarium Root Rot

Abstract

Asparagus (Asparagus officinalis L.) seedlings inoculated with the sicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum (Thaxt. sensu Gerd.) Gerd. & Trappe (GF) d Fusarium oxysporum (Schlect.) Snyd. & Hans. (FO) were grown under field and greenhouse conditions. In the fi, shoot volumes of GF-inoculated plants were greater than nonGF plants from the 3rd through the 13th month of growth. By the 14th month, GF-inoculated plants grown in high-P soils had significantly lower disease ratings than nonGF plants grown in low-P soils, and rhizosphere populations of FO were lowest in high-P soils, regardless of VAM status. In greenhouse studies, FO inoculation of VAM-infected asparagus plants reduced GF root colonization levels under well-watered (0 MPa), but not under water stress, conditions (- 1.5 MPa). Well-watered plants inoculated with both FO and GF were less diseased and sustained lower rhizosphere populations of FO than plants inoculated with FO alone. The differences in FO populations and disease ratings in these studies were apparently unrelated to final plant tissue P levels.