This section is from the book "Commercial Gardening Vol3", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Small dull-red caterpillars are often found in the centre of the stalk of the trusses of Apple blossom, and even in the leaf spurs.
These larvae cause the shoots to "flag ", and then gradually turn brown and die. These are Pith Moth larvae, and they often do much harm to bush trees.
The moths belong to the Tineinae. They have long, thin wings, edged with long fringes. The fore wings are black and rusty brown, and on the inner border some broken white marks. In B. vinolentella the head is black, in B. Itellerella it is white.
The moths appear in July and August; where they lay their eggs we do not know. The young larvae appear to live on the under side of the leaves in the autumn, and then make their way under the skin of the shoots near the base of a bud. In this position they form brown blisterlike areas, which have a small opening into them. In spring they work up into the bud, and live there, finally tunnelling the stalk, where they change to an ochraceous and mahogany-coloured pupa in early July.