Sawfly caterpillar - What to do?

[Jonny.D]

Had a look at the Gooseberry bush today and noticed a lot of damage and green caterpillars all over the place.




Shook the branches and killed as many as I saw.

Any advice on what to do next?

PS I'm in amazement that the ones that fell onto the ground were crawling back up the side of the pot.

[chrisdb]

I normally just pick them off and squash them between my fingers...

[cheops]

Although this is a bit late to help you with this bush - This is what I do. Because the sawfly eggs are laid together under a leaf when the eggs hatch they start eating that leaf and then spread out to the rest of the bush. I check daily and when I see a half eaten leaf I turn it over and sure enough there are many tiny caterpillars caterpillars just hatched. I remove and dispose of the leaf.
In your case I would spend a bit of time checking your bush and picking off any caterpillars. Shaking the bush does not get them all. Your bush will recover and any gooseberries will continue to ripen.

[MarkPelican]

Although it won't help this year, they pupate under the ground beneath the bush so hoe around under the bush to move the pupae up to the surface and the birds will eat them.

[chrisdb]

I've noticed a decrease in sawfly the last couple of years as the ground under the bushes has gotten cool and shaded by underplanted herbs and fruits. I regularly find frogs, toads and other wildlife down there. Not sure if something is eating / attacking the caterpillars or adults as they emerge or whether it's just luck.

[BUFFS]

I put some veg oil onto a good sized piece of cardboard that has been cut to fit around the main stem at soil level, and wide enough to cover below the branches, and then use a stick to really rattle the bush, the maggots drop onto the card but the oil stops them sliding off quickly, so the card is removed, flat as possible and laid on the lawn for ten minutes... after doing this 3/4 times before I now have a gang of birds twittering, waiting for me to move so they can dive in, and its like a rugby scrum, with them all shoulder to shoulder, hovering up all the offerings. the card can be used again, if you put more oil on and have anywhere to store it inbetween use...

[Jonny.D]

Thanks for all the tips

[4390evans]

Oh fab thread. I found my bush was obliterated the other day but there was no bugs etc it was literally over night!

[cheops]

Hi, 4390evans - sawfly larvae can completely defoliate a gooseberry and in such severe cases the production of gooseberries will be adversely affected the following year. However if you don't mind me saying so this can not be achieved by the larvae overnight. The sawfly will lay it eggs in a batch on the underside of a gooseberry leaf low down on the bush. This often means the hatched caterpillars are not noticed till they have caused havoc and have moved upwards on the bush to find more foliage. At this stage the caterpillars are large and have spread out all over the bush and now with numbers and bigger appetites they could NOW at this stage literally strip the bush of its remaining leaves overnight.
As I said earlier be prepared to check the underside of the leaves daily and you WILL spot a batch of eggs or a cluster of newly hatched caterpillars but whether eggs or caterpillars they are vulnerable as the removal of one leaf will destroy a whole community in one go.