Occurrence of Fusarium on leach pine cells from the USDA Forest Service Nursery, Coeur d'Alene, Idaho

Three hundred fifty Leach pine cells used to grow containerized conifer seedlings at the USDA Forest Service\ud Nursery in Coeur d'Alene, Idaho, were sampled for Fusarium and Trichoderma colonization. Cells were either\ud sampled prior to or after cleaning. Cleaning reduced Fusarium colonization from 86 percent of the cells to about\ud 50 percent. Cells stored for several months still contained high levels of Fusarium inoculum. Most Fusarium\ud inoculum was concentrated at or near the bottom of cells. Cells with high Fusarium levels had corresponding low\ud levels of Trichoderma and vice versa. Ability of the Fusarium isolates from cells to cause seedling diseases is\ud unknown, but Fusarium-caused disease is common at the nursery