Potatoes Update – Mid August 2020

Pests

The weather has been favouring slugs this season and it is worth doing some test digs to see if there is any sign of slug or wireworm damage to tubers. Wireworm damage tends to be small holes penetrating the tuber whereas slug damage tends to be more irregular shaped holes. Unfortunately nothing can be done for wireworm apart from lifting the crop as soon as it is practical to do so, as damage will only get worse the longer the crop is in the ground. For slug both ferric phosphate and metaldehyde are effective molluscicides and can be used to try to reduce slug damage but the optimum timing (just before crops meet across the rows) is now passed. If planning to use a metaldehyde product note the guidelines issued by the Metaldehyde Stewardship Group and in particular the requirement for a 10 metre buffer zone to the edge of the field where no metaldehyde pellets should be applied. The best timings now available are after these has been some rain which will draw slugs up onto the surface and after burn down, again when there has been some rain.