Fusarium dry rot of potatoes

Page last updated: Tuesday, 8 November 2016 - 11:40am

Please note: This content may be out of date and is currently under review.

Management

Techniques that can be used to minimise dry rot infection are listed in the table below. The main aim is to prevent infection by minimising damage to tubers.

Where seed tubers are cut, infection can be minimised by ensuring seed pieces are kept under conditions that promote rapid healing.

Several active ingredients are registered in Western Australia for control of fusarium dry rot. Consult your local agricultural supplier for currently registered products. Resistance to some active ingredients used in WA has developed overseas so it is important to follow fungicide resistance guidelines to prevent this happening here.

Ways to minimise fusarium dry rot infection
Growth stage	Symptoms	Management
Pre-plant	Dry rot present in seed	Use clean seed. Grade out infected tubers. If cutting seed, sterilise the knife after every bin/box/bag to prevent spread to healthy tubers. Clean shed equipment. Apply registered fungicides to cut seed. Maintain long crop rotations to prevent build up in the soil. Bring tubers out of coolstore and to room temperature slowly to minimise potential damage at planting. Do not store cut seed for longer than 10 days and keep temperatures below 16°C.
Planting		Plant when seed and soil temperatures are within 5°C of each other. Plant seed in sufficiently moist soil to promote quick emergence and wound healing. Avoid irrigation before emergence to prevent seed piece breakdown.
Growing crop	Non-emergence, wilting/yellowing (chlorosis)	Do not overwater. Monitor and record areas of fusarium wilt and be aware of these during harvest as they will have large amounts of spores.
Harvest/grading	Large amount of mechanical damage	Make sure tubers have good skin set before harvest. Slow the harvester/grader speed to minimise damage. Avoid harvesting in wet conditions. Do not leave tubers in direct sunlight or at high temperatures. Dry tubers as soon as possible after harvest to aid in soil removal from the tubers. Apply post-harvest fungicides adequately.
Coolstore	Rot occurring in bins	Cure the seed appropriately before coolstore. Maintain adequate airflow throughout the coolstore to prevent carbon dioxide build-up. Cool seed gradually to prevent condensation build-up on the seed surface. Maintain and clean the shed and storage area regularly. If rot occurs, separate infected seed from healthy seed.

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