My Solomon's seal plants have been defoliated by some nasty grey grubs,

What are they, and how can I prevent similar damage next year?

The grubs were the larvae of the Solomon's seal sawfly, an insect that can be very destructive.

The grubs remain just below the soil surface during the winter, and pupate in Spring emerging in May and June for egg-laying.

It may be possible to reduce attacks by carefully digging around the plant roots with a hand fork to expose the grubs,which will be eaten by birds.

To control the problem, spray the top and underside of the leaves with an insecticide containing fatty acids at the first sign of attack normally from May onwards.