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The small brown or green caterpillars roll the leaf edges
together and spin fin web of silken threads to hold the leaf in its
coiled position. The caterpillars can then feed
on the leaf tissue and the protective covering makes it difficult to
control by spraying. Sometimes known as the
Summer Fruit moth, but there is also another moth that bears this common
name. The moth is light brown in colour - almost orange at times, and is
active during May-June. With two generations
each year, the first eggs are laid in May-June - normally in batches of
50-100 in a circular cluster. The eggs are normally transparent, so it
is possible to see the development stage of the larvae - caterpillar -
inside the egg. The black head of the caterpillar is normally visible
just after eggs are laid.
The caterpillars that hatch, then feed on the leaves -
often spinning them together into a roll for protection. The
caterpillars also attack the fruit of apples and pears , causing
considerable damage. The best way of control is to pick off the affected
leaves. The caterpillar will either be visible , or hidden inside the
leaf.
Tortrix Moth inside protective web, ready
to emerge in September, then continue laying further eggs which will
then overwinter as larvae in cracks and crevices of bark.
The caterpillars when mature, will reach up to 20mm in
length, and reach this stage quite quickly from the egg stage - usually
in just two to three weeks. The caterpillar then pupates into a cocoon
inside a rolled/spun leaf, which then emerges into the second generation
in the year during August-September.
The later batch of larvae, from the August-September
moth generation tend to overwinter in a bark crevice, or fork of branch
- ready to emerge the following May-June to start the process all over
again.
It can be a severe pest of Apples, but also attacks
Pears. Pheromone are sometimes used commercially to trap the flying
moths, but not with a great deal of success.
Provado Systemic will do the trick - as will
Bifenthrin if used as a contact insecticide. |
