August Pest of the Month: Fusarium species in production nurseries

Fusarium species provide a major challenge to successful nursery production, particularly the special host adapted forms of Fusarium oxysporum which cause vascular wilts.

These are very strong pathogens capable of causing devastating losses. Plants systemically infected with Fusarium wilt pathogens cannot be cured and must be destroyed as soon as possible.

Symptoms caused by Fusarium wilt and other species of Fusarium include wilt, dieback, root rot, crown rot, cutting rot, damping off and sometimes even leaf spots.

Fusarium wilt of basil (left) and healthy plant (right).

Diseases caused by species of Fusarium can be indistinguishable from other pathogens and therefore it is important to have symptomatic plants tested to identify what has caused the problem. Since plants cannot be cured, management must focus on breaking the lifecycle and preventing future infestations.

Most preventative measures involve a high level of nursery hygiene, growing resistant varieties, where possible, managing nutrient levels, propagative material and other nursery inputs (e.g. water, media etc).

For more information on the biology, Fusarium species host range, symptoms and management of Fusarium refer to the updated factsheet. Other factsheets that may assist include those on preventing disease, managing disease transmission, and the soil borne disease management plan.

Remember, all production nurseries receive 6 free diagnostic samples per year until the end of 2025 through Grow Help Australia through a nursery levy funded project (NY20000).