Seed-bed quality key to reducing slug seed hollowing this autumn
With seed beds yet to be made in this wet season for some winter wheat crops, growers are being told that they must take extra care so that seeds don't succumb to hollowing by slugs.
This is the first autumn without the insecticide seed treatment, Deter and while it was primarily used to protect cereal crops from barley yellow dwarf virus (BYDV), it also had a repellent effect against slugs around the treated seed.
With slugs thriving in the current seed-bed conditions, Hutchinsons' technical manager, Dick Neale, pointed out that seed hollowing was often the result of poor cloddy seed-beds, which growers using Deter could get away with. That is no longer the case.
“Now growers need to think about cultural methods, which includes addressing seed-bed quality. Slug control is about a good, friable seed-bed and good seed-to-soil contact to limit movement," he explained.
In direct drilling systems, there is still a 'seed-bed' where the tine or disc coulter had worked and Mr Neale added that if using tine drills, operators should ensure soil is adequately reconsolidated behind the tine to limit slug movement down the row.
Similarly, if using a disc-based direct drill, the slot opened up by the coulter should be closed to seed depth and not just on the surface. “Otherwise, slugs get in the crevice and will ust follow the seed down the row,” he said.
High risk situations arise in plough and deep non-inversion systems where a loose, cloddy structure is created on heavier soils allowing free movement of slugs through the profile and around seed. This was a situation where shallow, non-inversion tillage could help reduce pressure, damaging eggs and exposing adults and juveniles to predation on the surface.
“In shallow systems, you can get good tilth and a well consolidated seed-bed, that is brilliant for controlling slugs.”
In addition to cultural methods, agronomist, Antony Wade, advised monitoring with traps in stubbles or cultivated ground ahead of establishment and treating with a ferric phosphate-based pellet immediately after drilling if slug risk is identified.
“I have moved over [to ferric phosphate] from metaldehyde over the last two years and have been happy with its performance. There are also no concerns when using the product around watercourses. I would recommend going with a premium pasta-based type, as the pellets are much more resilient in wet conditions,” he said.
That durability may be needed, according to Certis' western regional technical manager, Geoffrey Bastard, who said a wet UK-wide forecast was likely to increase slug pressure considerably.
"Sluxx HP pellets contain an anti-mould agent, which will maintain palatability and protect the crop, even after periods of heavy or prolonged rainfall. Keep monitoring after initial applications, as follow up treatments will be needed where slug risk remains high,” he said.