Tree coverings transform into white shrouds due to the presence of White Ermine Moth Caterpillars. - Trees Enshrouded in White Sheets Due to Larvae Presence
Large Webworm Infestations Cover Berlin's Trees
In Berlin, a multitude of trees are currently adorned with white veils, as revealed by city nature expert Derk Ehlert. The cause of this peculiar covering is the larvae of the webworm moth. Unlike oak processionary caterpillars, these larvae do not possess hairs; instead, they protect themselves by weaving webs, hence the name 'webworm.'
This year, the webs spun by these larvae are notably large and impressive. Some trees are completely engulfed in the silk threads. Ehlert attributes this to the four months of drought that have led to imposing webs unlike those seen in recent memory. Light rain merely beads up on the threads before disappearing with a good rain shower.
Regarding any potential health risks, the larvae of the webworm moth pose no danger to humans, according to the expert. Although they eat fresh tree growth, even defoliating entire trees in some instances, they do not harm the trees themselves. This phenomenon has been present for thousands of years, and trees have adapted accordingly. "They simply grow new leaves," says Ehlert. Trees in good health and proper care will experience no negative effects. Species such as flowering dogwood, cherry plum, and common medlar are not exempt from these infestations.
In one instance, there were hundreds of larvae found in a single nest. A single larva can weave up to ten meters of thread in a single day. For birds, these insects serve as an essential food source. From June to July, the moths pupate and transform into "beautiful butterflies," as described by Ehlert.
If one encounters an infestation in their garden, the webs can be removed through pruning or the use of a strong water jet. The introduction of pesticides is unnecessary and ineffective.
Webworms, typically the larvae of moths in the family Saturniidae or the fall webworm (Hyphantria cunea), progress through several stages: egg, larval, pupal, and adult. While large webworm infestations in Berlin may not be common, they are found in various parts of the world. These insects can infest trees, particularly those from the Rosaceae family, although their prevalence can vary based on location. Webworms can cause significant damage to trees by consuming leaves, which may stress the tree and weaken its defenses against other pests and diseases. Despite this, webworms perform a crucial role as a food source for various bird species, reptiles, and insects. Controlling infestations typically focuses on maintaining healthy tree conditions and utilizing biological control methods whenever possible.
The Commission could propose a directive on the protection of workers, not just from the risks related to exposure to ionizing radiation, but also from the potential health risks associated with manipulating large quantities of webworm threads in home-and-garden settings, given the increase in their numbers. A lifestyle choice that promotes the cultivation of trees resistant to webworm infestations, such as flowering dogwood or common medlar, could help minimise exposure to these insects at home.
