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hi im relatively new to greenhouse gardening, i have just found tiny transparent caterpillars with black heads on my tomatoe pots. does anyone have a clue what they are and wot to do with them? jo

thanks for your help guys!


Obviously no-one knows! If you ever find out from Mr Google or anyone, it would be interesting to know :- )


jo, most immature (baby) caterpillars are usually close to transparent with black heads. In short, get rid of them. No caterpillar in the vicinity of tomato plants will ever have good intentions.


Probably of the moth family. Control by squashing them - simples.


Hi thanks everyone. have spoken to RHS this morning and think they are fungus gnat larvae, millions of them so not possible to just squash them unfortunately! 


An organic contact spray like pyrethrum will knock them over but you'll have to keep a close eye out for their return.

oh thanks so much, is that ok with veg do u know?


Yes, it's derived from Chrysanthemums. You wouldn't use it on baby seedlings - well, you wouldn't spray most things on baby seedlings. With crops, you can harvest the day after spraying. Washing the crop, obviously.

It only works on contact with the pest, it's not systemic - meaning it doesn't penetrate the plant and stay there for a lasting effect. Which means you have to respray if the pests return, if it rains, etc.

Or, if you want to make your own spray, the garlic spray is the classic home gardener's weapon against caterpillars and the like. There are literally dozens of recipes. I make a combined garlic/chilli spray. I toss a head of garlic, a couple of hot chillies, a couple of squirts of washing-up detergent, a glug of oil and 4 or 5 cups of water into a blender. Blitz, strain out all the solids, then add another cup of water. Pour it into a spray bottle with an adjustable nozzle, label it, and attack your pests. Again, it's only a contact spray. It doesn't have residual properties.

It's a bit pongy, but it works!

How long would your spray keep for while still being effective.


I make enough to last about six months before making more. It's still effective after six months.

you are amazing you lot! i got the pyrethrum spray and have also made the garlic chilli spray. im armed and ready for action!! thanks so much everyone x


Goodoh. Don't forget they're contact sprays. You have to hit the critters with the stuff and hit them again if they return. Neither spray has any residual effect.

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