Slug Control in OSR

A wet start to harvest could well increase the threat of slug damage on the establishment of OSR, especially at the cotyledon stage up to the four true leaves stage of the OSR plant.

Winter cereals will also be at risk from damage from slugs, especially winter wheat grown after OSR. Slugs can be attracted to the drilled seed when it has taken up water from the soil. The slugs will destroy the growing point and therefore kill the embryo. Slugs will be a threat to cereal crops up to tillering.

Due to the weather conditions, slug breeding would likely to have continued as the wet weather and cooler temperatures have been near or around the optimum breeding conditions at 17 degrees. Each slug can lay hundreds of eggs and the hungry juveniles will hatch in about 2 weeks after the eggs have been laid.

Trapping should be used to ascertain slug populations, and should be done by using a small amount of chicken layers mash covered by a plastic container around 25-30cm in diameter prior to any cultivations (as this can underestimate slug populations). Traps should be left over night and inspected in the morning before the sun heats up the trap allowing the slugs to leave the trap. Traps should be set in a W pattern across the field partially concentrating on known problematic areas 9 traps/ field and 13 traps if the field exceeds 20ha.

Threshold limits for OSR are 4 slugs/trap in standing cereals and 1/trap in cereal stubbles.

OSR variety’s low in glucosinolates can be more at risk from slug damage, so timely application of slug pellets is important for achieving the best control.

Using a good quality durum wheat ferric phosphate pellets can be more cost effective due to their superior attractiveness, ballistics/spreadability, palatability and persistence. Ferric phosphate works differently to metaldehyde due to it being a stomach poison which stops slugs feeding and the slugs often retreat under the soil surface and die between 3-6 days after application.

It is now a legal requirement to have all vehicle mounted pesticide application equipment tested by NSTS (National Sprayer Testing Scheme).

Don’t forget to use up any Metaldehyde slug pellets you have in stock this Autumn as the farm use up date is 31st March 2022.

You can contact our team today to discuss your pellet and agronomy requirements for slugs by calling 01243 755610 or emailing chems@bartholomews.co.uk