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Slug control solution for potatoes

Reliable slug control is vital for potato growers; damage to yield and product quality is a risk growers can’t ignore.

Reliable slug control is vital for potato growers; damage to yield and product quality is a risk growers can’t ignore. 

Tuber hollowing can render crops unmarketable, explains Alan Horgan, Certis’ Technical Officer. “There are extremely small margins for error when it comes to slug damage in potatoes due to demands made by processors.

“Growers need to consider the field and crop history when managing their slug control as with potatoes it is particularly important that the slugs are killed whilst they remain on the surface, before they have chance to start feeding on the tubers,” adds Alan.

“Potato growers also have the added challenge of the impending loss of methiocarb, which is historically the most popular slug pellet control choice for this sector. Ferric phosphate is a very real option for potato growers and can fill the gap left by methiocarb, but many growers are understandably nervous as it is a relative newcomer,” he adds. “Nevertheless it does tick all the boxes and meets the demands made on a potato slug control solution, but with the added benefit of having a very low environmental impact ," explains Alan.

“More and more growers are turning to ferric phosphate in light of restrictions placed upon metaldehyde and the imminent loss of methiocarb; the other two main slug pellet options.”

There are also zero buffer zones when applying Sluxx (ferric phosphate) which does make it an attractive choice for potato growers, points out Alan.  “Growers are able to treat their high value crops right to the field boundaries, while the flexible dose rate of up to 7kg per hectare and a total of 28kg per hectare per crop also allows growers to treat based on the slug populations that season.”

Alan does point out that growers need to be aware of the different mode of action presented by ferric phosphate. “Monitor your slug populations and the crop risk based on field trap results. Whilst Sluxx doesn’t present you with many visible dead slugs, you will see an immediate cessation in feeding post application.” 

Case Study

Graham McEwan, of A M McEwan Farms, who farms 850 hectares in Arbroath has been using ferric phosphate across all of his crops, from winter wheat, to oilseed rape and 304 hectares of potatoes.

“We have used Sluxx for over six years, following a recommendation from our agronomist,” he comments. “We first turned to ferric phosphate due to a desire for a more effective environmental option, whilst from a management point of view we also wanted to reduce the amount of packaging to aid filling the spreader.”

Of our 12 varieties, Maris Piper is the most susceptible in terms of slug damage, explains Graham. “We apply slug pellets little and often; less than the recommended label rate, but we are still seeing excellent slug control, even on the high risk varieties.

“Every second blight spray, at 14 day intervals, we apply Sluxx at a rate of 2.5kg per hectare,” adds Graham. ”This suits our management system and we are able to target the slugs on the surface before they damage the tubers.

“We start applying slug pellets pre canopy closure right through to desiccation, and even though we are applying pellets every two weeks for up to five applications, we are only using a maximum rate per crop of 10 to 14kg per hectare. This is nowhere near the recommended total label rate of 28kg per hectare per crop.

“We know Sluxx is reliable and working hard when we see the sudden drop in slug activity and the cessation of feeding following application, but unlike methiocarb and metaldehyde you don’t see dead slugs on the surface or excessive slime trails,” notes Graham.

Ferric phosphate has a different mode of action, which requires growers to adapt their monitoring, as slugs retreat underground to die. “It’s a different way of working for many farmers,” he says.

“Our confidence in the product developed as our experience with Sluxx grew over the first two seasons we used it.” Graham concludes, “I would recommend growers try it and see for themselves.”