3 November 2019

Customer Question – Caterpillars

Q. “For the previous few years a tree in my garden is completely destroyed shortly after it gets its leaves. By May it has lost all of its leaves. Last year I noticed the culprit was a very small caterpillar – see picture below. On every single leaf was hundreds of these tiny (1-2mm) caterpillars. I think it might be sawfly (which I believe I saw the adult flies towards the end of May). I have attached two pictures form last year, one is where they were still eating the leaves, the second one is the aftermath where the larvae were much bigger and the leaves destroyed. First of all is my identification of them as sawfly larvae correct? Second of all, is there any kind of biological control (e.g. nematode) that I could use this year if it happens again?” from Robert

A. Thanks for the message and any small caterpillar like this is going to be a variety of sawfly and the good news is the Nemasys Fruit and Vegetable Protection nematode is very effective against all species of sawfly. It is sprayed on 3 times at 7 day intervals when the caterpillars are 1st spotted which is normally in mid-May. As your garden is normally stripped in May I would aim to treat weekly from late April through to the end of May and then re-apply as needed from then on. How big an area do you need to do – each pack treats up to 60 sqm. The programme of applications is going to be best as it is a perishable product, so if you work out how many packs you need each week, we could then send you fortnightly deliveries (enough for 2 weeks each time) from late April to the end of May? Let me know what you think and if you want me to work out a programme? Kind regards Jon @ Green Gardener