I have used GG's Nemaslug for several years and they have been very effective in keeping slugs and snails under control in my borders. This time I bought Nemasys ant nematodes too, but was surprised to find when opening the packet that they do not actually kill the pests (unlike the slug type), which I don't think was clear on the website. They are simply a deterrent, to persuade the ants to move their nest elsewhere, which is not very helpful in a big garden. And then you have to ensure the ant's nests are moist before application, and remain moist for 2 weeks after application. I ordered the nematodes for when a rainy period was forecast, but they arrived after it had passed the Met Office forecast was a bit off). It's too early to say whether they have been effective, but if they are as good as Nemaslug I'll be happy. That said, the packet delivered by Royal Mail was hot to the touch when pushed through the letterbox - presumably from sitting in hot vans for hours - and both products need to be cool (you have to store them in the fridge until you use them) - so I hope they were still alive when I applied them.