As autumn drilling follows a very wet period, slugs and their managementshould be a major consideration for wheat growers this autumn.
The wet weather in late July through August and into early Septemberwill have been very favourable for slugs, says Dr David Glen of StylomaResearch.
The main pest species, the grey field slug (Deroceras reticulatum)breeds rapidly when weather is wet at this time, so there will be lots of smalljuveniles ready to attack autumn sown crops. Weight for weight they tend to kill more wheat seeds than largerindividuals which find it harder to move through the seedbed, advises Dr Glen.The damage risk also depends on the weather from now on, further rainfall willaffect slug activity and survival together with the ability of farmers toproduce fine, firm seedbeds.
Slugs are a concern for Philip Huxtable, Director of Arable Productionof the JSR Farming Group based at Southburn, near Driffield, E Yorks. Alongwith spring crops and 400 ha of environmental schemes they grow over 2800 ha ofautumn sown crops. As a LEAF demonstration farm they take great care to ensurethat they minimise the environmental impact of their farming operation. At JSRwe take a managed approach to slug control to ensure we stay within themetaldehyde stewardship guidelines, he says. The moisture is a bonus as faras getting crops away, but the slug risk needs to be managed.
Despite the wet weather and the consequential lack of dust cloudsbehind the drill, we are achieving good seedbeds at the moment. Fine seedbeds help to inhibit slug movementand, along with the use of Redigo Deter (prothioconazole + clothianidin), allowthe crop to get off to a good fast establishment. We use Redigo Deter on allour wheat and barley to help control a range of pests and diseases, especiallyBYDV and grain hollowing by slugs in wheat. Its use also helps us to manage our heavy autumn workload, as it reducesthe number of times we spray or apply slug pellets.
Once the crop is established, we set up traps to monitor slug activityand treat with pellets as appropriate, switching products if necessary toensure we stay within metaldehyde use guidelines.
Peter Stacey of Bayer CropScience confirms that prevention of grainhollowing of wheat by slugs is one of the many reasons that Redigo Deter is apopular choice for both early and later sown crops. The later drilled cropscan be just as much at risk of damage from pests and diseases as early drilledfirst wheats and the slower growth means any attack can cause greater damage than forfast-growing, earlier sown crops.