As the key slug control timing in many potato crops approaches growers are urged to select a durable slug pellet, lengthening effective control once canopies close. Although dry conditions have prevailed for much of spring, the preceding mild winter beforehand would have maintained slug populations, according to independent potato specialist Martyn Cox.
Although dry on top, he says ridges have mostly remained moist at depth up to this point and there is potential for keeled slugs – the main threat to potato crops – to move up the profile once irrigation starts.
“Just because there’s been little rain, don’t think the slug risk isn’t there. As with any pest, risk assessment is key when deciding on pellet treatment. We usually apply at mid row closure and top up regularly where necessary,” he explains.
Mr Cox says his growers have managed slugs well with ferric phosphate pellets since other active substance options have been withdrawn, but there are clear differences between product formulations that should be taken into consideration.
Pellets that don’t spread well are a no-no and those same pellets tend to break down much faster after application, particularly in moist conditions typically found under irrigated potato canopies.
“Pellets must hold together well to get the baiting points where they need to be, and offer any decent period of activity,” he explains.
The durability of Sluxx HP is well proven in irrigated trials, but new work in Germany has added to the product’s credentials for use in spring crops like potatoes, according to Certis technical specialist Harry Raley.
In a caged arena experiment carried out by European research organisation EcoCare in 2021, the reduction in feeding achieved with Sluxx HP and a competitor at 10C and 20C was tested. It showed that both wet processed pasta-based pellets performed well at 10C, but at 20C feeding was reduced by Sluxx HP by 85% after eight days, compared to just 3% with the alternative pellet.