Using nematodes to get rid of sawfly

Tiffany Daneff / 20 September 2016

Tiffany Daneff marches into battle against the gooseberry sawfly armed with 10 million nematodes.

I thought it was all plain sailing from September, that the days of troublesome pests nibbling at the veg would be over, and that I could enjoy a nice relaxing Indian summer, feet up, reaping the harvest.

But, what this? While out picking yet another punnetful of raspberries for breakfast the other morning – and realising why it is that proper gardeners actually tie their raspberry canes into supports (you can reach the fruit without being soaked in dewy leaves/scratched etc) – I saw that something has stripped half the leaves from the gooseberry.

We are not talking just an unsightly nibble here and there. This is all out destruction, total stripping to the bone. No quarter.

The culprit is the gooseberry sawfly which also feasts on red and white currants. (Yes, we have those too.) And the best treatment, it seems, is to water on some nematodes.

What are nematodes?

Now, I have read about nematodes often enough, but I have never used them. I’m not sure why given the good reports. Nematodes, if you don’t know, are microscopic worms. By harnessing specific nematodes that predate on particular pests scientists have created biological protection systems that are easy to use and non toxic. They are even okay for organic gardeners. So what’s not to like?

I discovered that Nemasys Biological and Fruit Protection attacks the sawfly. Even better it targets ants (which are a real nuisance here) and leather jackets (which, for the first time have appeared in the lawn). So I ordered some online and a small plastic box containing 10 million nematodes duly arrived complete with instructions that they be put straight into the fridge. They look like a little yellow heap of sawdust and have a sell by date by which you must use them or they will, presumably, have perished.

So how to use them? First you make a stock solution which you then dilute and spray onto the affected areas. It does say on the packet that you must treat the leaves when the pest is present and although I can’t actually see the critters I can see the daily damage so I assume they are present.

It’s all quite straightforward – you just follow the very clear instructions - and the only frustration was the fact that there was way more solution than I needed and you can’t save it. Two more applications are required, at weekly intervals for which you need to open new boxes of nematodes. And that’s it. Nothing left to do but wait.

Find out more at

To fill in time I visited the Scarecrow Festival at Harpole at the weekend. It’s been a particularly bumper year for village fairs and fetes. Here are some snaps…..Much jollier than the pictures of the gooseberry I think you’ll agree.

Scarecrow festival

Note for the diary: Althorp Food and Drink Festival September 24 and 25

If you are in Northants on Saturday and Sunday 24th and 25th September head for the Althorp Food and Drink Festival. There will be lots of local producers, talks and demonstrations from the likes of chef and restaurateur Aldo Zilli, lovely Bake Off baker Martha Collinson and Italian pasta maker Carmela Hayes. And, my favourite, is the fab Richard Coles, our local priest and ex rocker, who’ll be talking about what it was like being on celebrity Masterchef, among other things. Worth going just for Richard!

Ticket start at £6.50 for adults, children aged 12 and under go free. There is also a ticket option for those also wanting to visit the house. To purchase tickets please visit the Althorp Food and Drink Festival website or call the booking office on 01604 770107.

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