Invasion of white clover roots by fungi and other soil microorganisms

Root invasion of 10–to 30–day–old white clover seedlings by microorganisms from two Manawatu soils was studied by isolation methods and microscopy. Endoparasitic nematodes (Heterodera trifolii Goffart and Pratylenchus sp.) were common in all roots. Roots heavily infected with H. trifolii were stunted. The internal root microflora of young seedlings included Rhizobium trifolii Dangeard, 1926, mycorrhizal fungi, actinomycetes, oomycetes, unidentified thalli within epidermal cells, Fusarium oxysporum Schlecht., Cylindrocarpon destructans (Zins.) Scholten, Codinaea fertilis Hughes & Kendrick, Phoma chrysanthemicola Hollos, Ceratobasidium cornigerum (Bourd.) Rogers, Bimuria novae‐zelandiae D. Hawksw., Chea & Sheridan, sterile dark mycelium, and species of Fusarium, Penicillium, Chrysosporium , and Chaetomium . These organisms were also the main rhizoplane flora. Non‐mycorrhizal fungi formed only limited infections and probably caused little root damage. Techniques used here seem promising for further studies on the range and importance of root‐invading organisms in other pasture soils.