Effective control of slugs is a not a complicated science, but it is easy to overlook the factors that make it achievable.
The success of any strategy is largely determined by two factors: environmental conditions at the time of application and the type of pellet used. There is very little that as a grower you can do to influence the former, but there is no reason for not mitigating the environmental pressures of the latter by selecting the best pellet available.
Think of pellet performance as the difference between a two-wheel drive and a four-wheel drive tractor. In easy conditions the two-wheel drive machine will probably manage just fine, but when conditions deteriorate the extra performance of a four-wheel drive tractor is clear. The same is true of slug pellets: TDS is the ‘four-wheel drive, dual-wheeled’ slug pellet and it outperforms all others in tough conditions.
There are four characteristics that determine pellet performance: ballistics, palatability, field persistence and palatability. As the European leader in slug pellet technology we know a few things about these attributes and breed (yes, we actually breed) about 30,000 slugs a year to test pellet performance and efficacy levels.
Two of these characteristics – attractiveness and palatability – are determined by the quality of the bait used to deliver the active substance: metaldehyde. This is why TDS (enhanced wet process) pellets use durum wheat flour rather than ground wheat which is commonly used in dry process types.
Slugs are discerning eaters so it is no surprise that they find durum wheat flour more appetising than ground wheat. Using a tastier pellet also ensures the slug ingests sufficient of the active substance to cause death whereas poor quality pellets tend to leave a nasty taste in the mouth and result in the slug showing less interest in pellets the next time they are encountered – a behaviour characteristic experts have termed ‘bait shyness’.
The remaining characteristics – ballistics and persistence – are largely determined by pellet size. If you think about it this makes great sense: which can you throw further, a table-tennis ball or a cricket ball? Which erodes faster ice-cubes or crushed ice? When put like that it seems so obvious, but the common factor in both these examples is mass, importantly the ratio of mass to surface area.
To achieve a consistent spread across the ground a pellet needs adequate mass. The smaller the pellet the less its mass and the less energy that can be imparted to propel it. This is why larger pellets spread better and why a cricket ball can be thrown further and with greater accuracy than a table-tennis ball.
Persistence is the term used to describe how long a pellet will endure in the field environment before breaking down. As with the ice-cube example above, the greater the surface area the faster the rate of erosion. This is why the preoccupation with excessive baiting points is one of the big myths of our time.
As a grower you will be seeking to achieve effective control with a single application. Ensuring this requires using a pellet designed to last several weeks. Smaller pellets are simply not capable of withstanding the environmental rigours that exist at the time of application.
It might seem advantageous to have many pellets per square metre, but ensuring sufficient baiting points to deliver effective control has to be balanced with the need to give lasting protection, in some cases up to several weeks. Independent trials have shown that just 30 pellets per square metre is sufficient to deliver effective control.
TDS pellets are the standard by which all others are judged so do not be misled into thinking smaller is better. Chose TDS, because size matters.