Gooseberry Sawfly :(

[Penellype]

My gooseberry bush is being attacked relentlessly by sawflies. despite picking off as many catrerpillars as I can find every day, I feel I am fighting a losing battle.

The bush is only a year old. I need to pot it on into something bigger and have in mind a raised bed, which I could fit debris netting over after the bush has flowered. Does anyone have any experience of protecting gooseberries with debris netting, and if so, did it keep the sawflies out? Or are they simply small enough to squeeze through the holes?

[Jungle Jane]

Is the fruit being affected? I had sawfly larvae on my strawberry leaves but not in any of the strawberries. I've read they pupate in the soil,so would you need to sit the plant in water & rinse out the compost it's in? I'm thinking of moving my strawberry patch,but a sawfly will come & find them wherever they are & lay eggs in the leaves,I wonder if spraying the leaves with garlic would help? Never tried but need a cure too.

[Penellype]

They don't eat the fruit, but they do eat the leaves - ALL of the leaves, very quickly. The problem with this is that the following year the bush has not got the energy to make much fruit.

[Jungle Jane]

Rhs website says the sawfly has four generations from April onwards so in march if sprayed with garlic,maybe it would hide the scent from the sawfly like it does with aphids? It might confuse them too in the same way & they won't want to lay eggs on what they think is garlic (they ate most of my strawberry leaves,I've got a couple of runners in pots but noticed holes there too). Four generations would need repetitive sprays. I was concerned if you contained the bush with sawfly pupating in amongst the roots,they would be trapped in there?

[Penellype]

Yes that is my concern too - I'd have to play it by ear. I intend to mulch the area with weed suppressant fabric after planting which I hope will stop most of them pupating in the soil.

[mothhawk]

Sawflies are only about 1/4" long, so may get through debris netting. And the first adults emerge in April, so waiting till the gooseberries have flowered would be leaving protection too late unfortunately.

On the plus side, gooseberries are self-fertile and don't need a pollinator so you can keep them covered all year round.

On the minus side, as you have caterpillars already, the sawfly pupae may already be in your soil, as they have 3 or 4 breeding cycles a year.

I would dig it up, wash off all the soil, replant it somewhere else, surround it as closely as you can with weed membrane and cover that with grit or gravel, (so future larvae can't get in the soil) and maybe protect year long with enviromesh.

Having said all that, mine are underplanted with lavender and the sawfly don't seem able to find them, especially now it's flowering. I use lavender angustifolia which grows tall and at this time of year hides the bushes completely.

[roitelet]

Sorry to say but a systémique insecticide is the only answer. I don't like to use it but once every three years seems to do the trick. Use it before they flower at the first signs of damage and it will keep them under control. Or you could use it after the fruit has been picked if there is an infestation.

[Penellype]

Thanks for the answers. Thee plant is currently in a pot and needs repotting, so digging it up and washing off the soil isn't a problem. I think I will wait until late autumn when the leaves have fallen so that there is no danger of any latecomers remaining. I'd love to grow lavender, but I've tried 3 times and killed the plants within 6 months on each occasion. I guess they don't like a fully shaded bog!

I'd rather try the mesh before resorting to insecticide - my local garden centre sells some which is very fine and hopefully will be small enough to keep the critturs out. I didn't realize that gooseberries didn't need a pollinator.

I was going to plant a blackcurrant in the other half of the bed (both cordons) - could that be covered all year too?

[mothhawk]

....I was going to plant a blackcurrant in the other half of the bed (both cordons) - could that be covered all year too?

Yes, it's another self fertile plant, although, like gooseberries, bees will go from flower to flower, which probably improves the setting rate, rather than relying on the wind to shake the flowers about.

[Penellype]

Thanks, I'll have a go with the insect mesh and see what happens.

[chrisdb]

I had lots last year, but almost none this year so far. I'm not sure what the difference is, except that I have a much more mature ground-cover layer under and near the gooseberry bushes this year, including lots of herbs and a small but lively frog population.

I don't know much about what, if anything, eats gooseberry sawfly, so I don't know if I've just been lucky or if I've got some wild biological control of some sort.

EDIT: the other thing I have growing under the gooseberries are wild strawberries, which the birds love to steal. Maybe the same birds also like gooseberry sawfly eggs or larvae?

[Penellype]

Things have taken a turn for the worse this morning - I now have 2 varieties of sawfly . The earlier ones had green caterpillars with black heads which appeared one to a leaf and ate the leaves from the edges. These are reasonably easy to remove with tweezers, if you can see them. I was removing about 10-20 a day. This morning I have clusters of green caterpillars with black heads and black dots on the bodies, and there are about 20 to a leaf. I can't see how to get them off without removing the leaves, which will ultimately have the same effect as the caterpillars. I think I am going to try inspecting every leaf, then wrapping the bush in fleece to keep the blighters off.

This could take some time...

[Invicta]

Gooseberry sawfly

You don't need to cover Black Currants, unlike Red currants they are not affected by sawfly.

[Jungle Jane]

It's probably another generation of the sawfly then? Those 20 on the leaf would have spread like the others,good you found them where they just hatched. They can be squashed on the leaf,without removing the leaf? Leave the mess on there,let it be a warning to other sawfly (some bugs excrete fatty acids/smells when they're dead as a warning to others).

[Penellype]

It's probably another generation of the sawfly then? Those 20 on the leaf would have spread like the others,good you found them where they just hatched. They can be squashed on the leaf,without removing the leaf? Leave the mess on there,let it be a warning to other sawfly (some bugs excrete fatty acids/smells when they're dead as a warning to others).

Its a new generation alright but these are different coloured caterpillars. The analogy with cabbage white butterflies is striking - the green ones tend to be loners, while the spotty ones hunt in packs. What was left of the leaves was 90% caterpillar, so I nipped the leaves off and put the lot in the hotbin. I found lines of eggs along the ribs on the undersides of several leaves, and removed these too.

My fleece wrap didn't last long - its trying to blow a gale here. I went to the garden centre and got a pack of fleece pot covers, which fit nicely over the bush and have a drawstring at the bottom. I've pulled the string tight round the stem of the bush, so hopefully that will keep any more flies out, and if any caterpillars are left they will not be able to reach the soil to pupate. I may be living in cloud-cuckoo land here but I like to be optimistic . The fleece cover is green, so I hope enough light gets in, that seems to be the only issue.