Mountain ash tree

The Ash leaf-cone roller is one of many of our crawling and flying visitors who stop by, usually for lunch, and then move on, leaving little damage behind. These guys are newcomers here and have been around since the end of the 90s.

The adult females lay their eggs on the newly forming leaves. They hatch and the tiny larvae feed inside the leaves. Later they migrate to new leaves using long threads. It is in their last stage that they roll the leaf and prepare to pupate. Inside they spin a cocoon and after completing their last stage the adult moths emerge. They are small moths with a wing span of just over a centimetre in width.

The Ash leaf-cone roller causes no harm to the host Trees. The trace of their passing is cosmetic only and should not cause alarm.

Why not spray to control this insect? Insecticide spraying is just not good for the world. Many times other beneficial insects are destroyed along with the targeted species, which causes greater overall environmental harm than the slight Tree damage. Also, protected inside their cones the larvae are pretty much spray proof. Many times after the adult moth flies away, the cocoon will eventually blow away and the leaves unfurl.

There are rare cases when spraying still seems to be the right answer. A heavy outbreak of yellow-headed saw fly is one, when it comes down to either spray or lose the Tree.

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