Some microconidia are also produced within rotting tissue. White cottony masses on the diseased tissue are spores and mycelia of the fungus. These spores are blown or splashed to nearby plants or other healthy tissue. For many orchid plants such as dendrobium, new shoots are formed below the canopy of the older leaves. Thus fungal spores formed on older shoots easily splash or drip on young shoots emerging from the base of the plant.
Young shoots are very susceptible to infection and rapid disease development.
Likewise, fragile young plants in community pots are extremely susceptible to this fungus and many are killed. Since growers commonly salvage all plants that survive, the Fusarium will persist on mature plants and cause leaf, sheath, shoot, and flower rots. These plants serve as sources of inoculum, and disease spread within a greenhouse is insured by overhead watering. Insects, snails, and slugs also move spores from diseased to healthy plants. Fusarium will survive in diseased plant tissue for many months and spores will also survive in potting media and in the immediate environment of the diseased plants.