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cosmos & gooseberry sawfly questions
sanjy67
Posts: 1,007
hi, i have two questions to answer please 
1) fed up of picking od hundreds of dreaded sawfly grubs, so my question is twofold, do the grubs come up from the compost having been laid last year? and if so would it be a good idea to scrape off top layer and cover with a piece of corr matting cut to fit the base of the gooseberry (it's in a pot btw) would this a) stop them coming up and or stop the sawflies from laying eggs in the soil?
2) i have some cosmos seedlings i planted last week in a seed tray, they are already 3 inches with just their seedling leaves on. when i transplant them should i plant them up to their leaves as with tomatoes or will this rot the stems?
thanks in advance as usual
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Posts
Quite right about the sawfly larvae. The larvae drop off in the autumn and pupate in the soil, then emerge, mate and lay eggs on the leaves. The larvae then eat the leaves. All the leaves, in my experience!
Anything you can do to break the cycle will work, so yes - rake away the top couple of inches of soil and/or cover it with something impermeable to sawflies - coir matting would be good. You can also spray with garlic/oil emulsion which will at least discourage the little b*ggers if not actually kill them.
Don't know about planting Cosmos, but the usual rule is to plant at the same level.
When I initially pot on Cosmos seedlings, I do bury them an inch or so deeper. It stops them becoming so leggy.
When you don't even know who's in the team
S.Yorkshire/Derbyshire border
thanks everyone, i forgot i still had cosmo seeds hence why i have planted so late.
verdun, what do you use as mulch?