Steve writes
Hi, I have noticed that some of the plants I have been growing from
seed that I planted out, or are in pots outside, appear to have had
their stems shreaded, basically the leaves break away from the plant.
There are no other obvious signs of the leaves being eaten, just that
the stems. I can't work out if it's cold weather, slugs or aphids
(both of which are a problem in my garden). They tend to be plants in
the early stages of growth, not established ones but it's making a
serious dent in my collection!

Slugs typically eat the stems of seedlings, basically rasping away from
one side.
--
Kay