Outgrade potato piles can be a source of blight. In this article AHDB specialists in the UK are discussing blight control methods in outgrade and waste piles as well as best practice and tips for tackling this issue.
Outgrade and waste piles – a source of blight
Blight control does not start in the crop. It starts much earlier. Left uncontrolled, outgrade and waste piles act as a reservoir for blight infection. With ever changing genotypes within the blight populations, outgrade piles and volunteers can be an unwanted host for blight and a source of infection for commercial crops. Infected plants produce millions of airborne spores which can travel for miles
Blight control methods in outgrade piles
- Best practice is to adopt a zero tolerance approach to sprouting and production of green foliage on outgrade piles by tackling it early; preferably covering with black plastic sheeting. Covering the pile and ensuring the edges are sealed will prevent the escape of spores and reduce the likelihood of wind getting under the sheet. .
- Where sheeting is not an option, any sprouted outgrades can be sprayed with glyphosate (read more resistance management advice) but this is high risk as work has shown that blight spores continue to be released during the slow haulm kill with this herbicide. Waste piles should also be kept low to increase any frost kill and reduce the risk of volunteers emerging from depth at a later day.
- A further non-chemical option for smaller piles is to