Unseen sawflies!

Question ...

I have just found my favourite yellow, scented aquilegias stripped of their leaves! I seem to recall hearing about an aquilegia sawfly or something which could do this. I have cut the plant stems down and searched for pests in the surrounding soil, but found nothing recognisable. Anything I can do to prevent recurrence/break this pest's cycle/help the plants for next year? I also have the solomon seal leaf eating grub thing which will arrive any time now. I watch for it and pick it off, though it usually wins by stealth. Again, can I stop the cycle? Where do they go after the feast?

Answer ...

Both aquilegia and Solomon's Seal sawflies can strip plants of their leaves in no time. Their behaviour is similar, so is the treatment.

Adult sawflies lay small batches of eggs on the underside of leaves in late spring. When the larva hatch, they feed voraciously on the leaves for a while, before dropping to the soil and pupating around the base of the plant. The best way to deal with them is to keep a close watch on the plant and remove the larvae as soon as you notice leaf damage has started. It is essential to break the life cycle. Hoe around the base of the plant to expose larvae for birds to eat. Derris will kill sawfly larvae, but if you resort to this treatment, take care to use it after dusk, when bees and other beneficial creatures are safely out of harm's way.

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