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<div>Anthracnose crown rot of strawberry, caused by <i>Colletotrichum acutatum</i> (<i>Ca</i>), is an important disease in California nursery transplant and fruit production. In nursery plant multiplication, the disease can increase in wet years or with overhead irrigation and may reach epidemic levels when infected plants are moved to fields for fruit production. Cyprodinil/fludioxonil and azoxystrobin are currently registered as pre-plant dips of bare-root transplants. Additional management options are needed because of phytotoxicity concerns with cyprodinil/fludioxonil if roots are over-exposed to the treatment and presence of QoI resistance in <i>Ca</i> populations. The broad-spectrum biofungicide natamycin, never reported to develop resistance in filamentous fungi, was evaluated for its in vitro toxicity and as a dip treatment. Mean EC₅₀ values for mycelial growth of 45 QoI-sensitive and 29 -resistant <i>Ca</i> isolates were 0.996 and 0.902 mg/liter, respectively. Dipping transplants inoculated with QoI-sensitive or –resistant <i>Ca</i> for 5 minutes in 500 or 1000 mg/liter natamycin reduced plant mortality in the field by 58 to 95% as compared to the control (42% or 72% mean mortality for cultivars Fronteras and Monterey, respectively). Fludioxonil/cyprodinil reduced mortality by 86 to 100%. Azoxystrobin was only effective against QoI-sensitive isolates, reducing mortality by 80 to 92%. Based on this work, registration of natamycin as a dip treatment of strawberry transplants is in progress.</div>