Re-use of seedling containers and Fusarium circinatum association with asymptomatic Pinus patula planting stock

Fusarium circinatum is a pathogen causing serious post-planting mortality of Pinus patula seedlings in southern Africa. Containerised planting stock that is asymptomatic but associated with F. circinatum in the nursery is thought to be the cause of this problem. The aim of this study was to determine if re-use of seedling containers could be a source of inoculum resulting in asymptomatic planting stock and increased post-planting mortality of P. patula. Two experiments were conducted in successive years comparing nursery cull of symptomatic seedlings, seedling growth, association of F. circinatum with asymptomatic seedlings and post-planting mortality for crops raised in re-used containers, with and without sanitation, and factory-new containers. Each experiment consisted of a nursery production trial followed by out-planting into pots to assess post-planting mortality. Our results show that re-use of containers without sanitation increases the cull of symptomatic seedlings, incidence of F. circinatum ass...