The spores of the fungus can enter the tree through these wounds and establish an infection. Once inside the tree, O. novo-ulmi grows in the water-conducting vessels of the tree, blocking the flow of water and nutrients, which eventually leads to wilting, yellowing of leaves, and tree death. The fungus also produces toxic compounds that further contribute to the damage to the tree's vascular system and overall health.
This process begins when the spores of the fungus enter the tree through these openings and initiate an infection. As a result, O. novo-ulmi grows within the water-transporting tissues of the tree, disrupting the flow of water and nutrients, which ultimately leads to leaf wilting, discoloration, and tree mortality. The fungus also releases toxic chemicals that exacerbate the damage to the tree's vascular system and overall health.