Fusarium wilt of cucumber

Fusarium wilt of cucumber is caused by the fungus Fusarium oxysporum f.sp cucumerinum. It has been present in Australia for decades, but the first case in the Northern Territory was discovered in 2017. It is a soil borne disease which infects through the roots of cucumber plants, spreading up through the stem and causing the customary wilt and dieback. It is specific to cucumbers and can spread through the movement of contaminated soil, infected plants and plant material as well as through the air.

Symptoms

In seedlings, seed rot and dampening off can occur. Symptoms in older plants include wilting lower leaves during the day, with some recovery in the evening. With time, the wilting spreads to the entire plant.

Infected plants can show signs of leaf yellowing and when cut the vascular tissues in the roots and lower portions of the stem may appear yellow or tan. In severe cases, dried tan brown lesions may form on one side of the stem, extending from the base of the plant. Under humid conditions, spore masses can form at the base of the infected stem.

Management

As with many other Fusarium wilts, no viable chemical controls are available.

Control relies on good farm hygiene and prevention. Maintain on-farm biosecurity practices to prevent the introduction of this fungus onto your property (see the Come Clean, Go Clean factsheet on the DPIR website).

• Source clean seeds and planting material.
• Prevent the movement of soil and infected plant material onto or around your property.
• Clean and disinfect machinery, tools and equipment that have been in contact with infected plants or contaminated soil before moving to unaffected areas.
• Ensure visitors disinfect their shoes and vehicles.
• Plants showing symptoms should be reported to the Department of Primary Industry and Resources Plant Pathology laboratory.

If you see similar symptoms, please contact the Department of Primary Industry and Resources

Plant Pathology Laboratory

Phone: 8999 2218 OR

Phone: Biosecurity Hotline on 1800 084 881

Email: Plant.Pathology@nt.gov.au