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Stop slug populations in their tracks

Producers are being urged to beware of the threat posed by juvenile slugs, and be prepared for a rapid explosion in pest numbers should wetter weather prevail whilst establishing crops are still vulnerable to attack.

Slug egg hatch

Producers are being urged to beware of the threat posed by juvenile slugs, and be prepared for a rapid explosion in pest numbers should wetter weather prevail whilst establishing crops are still vulnerable to attack.

Agrovista agronomist, Tim Bullock, explains that slugs are hermaphrodites, and targeting juveniles before populations grow exponentially, is key to achieving control. “Slugs can lay up to 500 eggs over a period of several weeks, laying batches of 10 to 50 eggs at a time. When the weather is right, slug populations can explode following egg hatch.

“The younger the better when it comes to controlling slugs,” advises Tim, “As it can have a dramatic impact on the future population of the slugs.”

Ferric phosphate has been proven to be an effective control for slugs of all ages. In trials, for slugs up to a week old, over an eight day period following pellets being applied, ferric phosphate kept slug damage down to a manageable level of 10 to 15%, whereas in the absence of treatment, slug damage escalated to 90% during this timescale.

Up until now the weather has not been conducive to mass slug hatch and a proportion of eggs are in a dormant state, comments Tim. “As soon as we have some rain and the soil profile becomes more favourable to slugs, growers need to be aware that egg hatch could cause a sudden spike in slug numbers.”

“Close monitoring of freshly drilled crops is a must,” he adds. “Put slug traps out with untreated grain, banana skins or chicken feed, and check them early in the morning for slug numbers. If not checked early, slugs will start to move down into the soil profile and it will be hard to gauge numbers,” he warns. 

“We always recommend growers are very reactive when it comes to slug control and establishing wheat, barley or oat crops that are not yet at the two or three leaf stage.” He adds, “That’s why slug traps are vital to help growers be aware of the full picture.

“Derrex, a 3% ferric phosphate, is our pellet of choice as there is no environmental or buffer zone restrictions. This allows for effective slug control where there is demand, without causing concerns around metaldehyde exceedances.

“Ferric phosphate is highly palatable to young slugs, and Derrex has been proven to help control population spikes following egg hatch by being an extremely effective treatment for juvenile slugs. This can help limit slug damage to crops at this vulnerable time, when any damage from slugs is too much,” concludes Tim.