Have you ever heard of the Frost Moth? The insects are particularly easy to spot when they are in the caterpillar stage: the winter moth makes a cat’s hump when it moves.
But the nice-looking little caterpillar doesn’t come alone – and it can become a nuisance. Light green to brownish caterpillars hatch in spring, which are very voracious. They puncture the leaves from April to May, often only the skeleton remains.
The young fruits of the fruit trees also fall victim to them. But there is a way to make that difficult for the little animals. Therefore, it is best for hobby gardeners to attach glue rings around their fruit trees in the garden in autumn.
The glue rings keep the females of this species from laying eggs in autumn. They cannot fly and so they migrate up the trunk into the treetops in the coming months. There they expect the flying males to mate and lay their eggs.
The Bavarian Garden Academy advises that the approximately hand-wide papers, which have been provided with a special glue, are best placed around the main trunk below the crown branch.
But also posts for supporting the tree crown should be “glued” because they can serve as a bridge for the winter moth. The catch traps are best attached around the time of the first cold nights in autumn.
There must be no loopholes for the moths. Especially on older trees with gnarled bark, the area around which the paper comes must be smoothed out as much as possible. In addition, the catch rings are well lashed with cords at the top and bottom.
A disadvantage of this method of pest control: the buffet of caterpillars caught attracts birds whose beaks can stick together from pecking. It is best to offer the birds an alternative in the garden, such as a bird feeder.
The Garden Academy advises removing the glue rings by the beginning of March at the latest. Then other beneficial insects such as ladybugs and earwigs become active again and are in danger of ending up in the traps as well.
Nevertheless, this method has advantages: It is non-toxic and therefore comparatively environmentally friendly – and according to the garden experts from Bavaria also a very effective measure against the winter moth. Larger tree crowns could only be treated with sprays in an extremely laborious and inadequate manner.
As already mentioned, the great weakness of paper glue rings is that they cannot adapt perfectly to every tree bark. For example, older apple trees can have a very rough and ridged structure. Then the pests crawl up directly under the paper – this also applies to ants, which defend the aphids against predators in the crown.
There is an alternative for this: the glue, which can be applied directly to the trunk. This allows you to fill every gap with the sticky substance and prevent the winter moth from reaching the top. However, the disadvantage here is that the glue cannot be easily removed from the trunk.