Butterflies are nice in the garden but caterpillars can cause havoc. Brassicas like Cabbages, Brussel Sprouts, and Broccoli are particularly prone to attack from Cabbage White caterpillars as you can see from my veg plot above.
Prevention and Cure for Caterpillar Damage
- Encourage the caterpillar’s natural enemies, such as wasps and birds for an environmentally sound and least cost method of dealing with caterpillar problems.
- Picking off caterpillars one by one together with any eggs is satisfying but a bit tedious if you have a lot of plants.
- Spray with soft soapy water and drop any caterpillars you have picked into soap water.
- I could have used a systemic insecticide if the EU allows and I wanted food with a residue of chemicals but that was not for me.
- A contact insecticide relies on hitting the creatures before they have done the damage and is still chemically based.
- Netting the brassicas would be a sensible prevention measure. I do that to prevent pigeons eating the young plants.
- Buy a biological control like Trichogramma wasps.They will act as parasites on the caterpillars.
- Accept that you will get some damage for the joy you get from buttterflies.
And dont forget the neem oil! It means a bit of chewd leaves but once the azadirachtin chemical in the neem hits the caterpillars they lose all appetite . Definitely a good thing.
When I was growing up an old lady in our road used to pay the local children to pick catepillars off her cabbages. I think we used to get 5p which was a lot in those days…..
I have some brussell sprouts that are now about 2 feet high and they’re still netted against the birds. It has duped me into thinking they don’t need any attention but I noticed yesterday they have white fly (not sure about caterpillars). If I remove the netting to deal with the insects is it OK to leave it off now or will birds still go for them (the leafs are tough but the budlike sprouts might tempt me if I was a bird!). You’re thoughts greatly appreciated
Im growing sprouts and i am completely over run with caterpillars. I really dont mind them eating the leaves but will this effect the sprouts? Will they eventually start to eat them or burrow themselves in the sprout leaving me to eat it? Im a novice at this and this is our first yr of growing fruit and veg so any help would be appreciated
Best not to use insecticide now you are close to eating them. Pick off the caterpillars and put on the compost heap.
If there are still butterflies or moths laying more eggs you could cover the plants with horticultural fleece.
Looking at the advice (following my purple sprouting being dessimated by caterpillars!) I’m going to try the Trichogramma wasps next year, plus netting. I’m guessing that the soapy water treatment would also kill my wasps? Has anyone got any experience on this?