Mistelmosterei

 a pest becomes a saviour

Orchard meadows are arks that have fallen out of time for old varieties that have become rare; a diverse fauna that can survive between the trunks and in the protection of the green crowns. But it is not just climate change that is threatening the meadows; mistletoe is invading the stands and draining the trees of their water and strength. But what if mistletoe could be used to earn money? Their berries, which can be utilised as a raw material for a high-quality biological glue, offer an opportunity to do so. The Mistelmosterei wants to obtain this glue: The mistletoe is professionally harvested and a special process is used to separate the seeds and fruit skins from the sticky fibres of the berries. The result is a plant-based glue that contributes to the preservation of orchards.

student:Emilia Sonntag
project:

The Plant Project
– Resilience Part II
year:2024

Modern food cultivation is characterized by monocultures, a low diversity of plant varieties and the intensive use of strong herbicides, pesticides and fertilizers. In contrast to this are the orchards, a form of fruit cultivation that not only dispenses with environmentally harmful practices, but also creates a biotope for up to 5000 species of animals, plants and fungi. On the 300,000 hectares of orchards in Germany, 6000 different types of fruit are cultivated. This special cultural landscape creates a symbiotic relationship between humans and the environment. The fruit growers get fresh fruit, but without their care the meadows become overgrown and this unique habitat disappears. Unfortunately, this is currently happening at an alarming rate. A lack of care – due to ageing owners, and economic viability, land conversion and, last but not least, climate change are endangering the orchards. One pest that has come under particular scrutiny in recent years is spreading rapidly – mistletoe. This semi-parasite invades the branches of soft woody plants such as fruit trees. Although mistletoe itself carries out photosynthesis, it draws water and nutrients from the host tree. A healthy tree can withstand these uninvited guests, but fruit tree populations affected by climate change have great difficulty in compensating for this loss. It is therefore essential to remove the mistletoe in order to preserve the trees. However, professional removal is expensive and removing it yourself is possible but very time-consuming. So how can incentives for mistletoe removal be created?

The solution could lie hidden in the berries of mistletoe. A study from 2022 by the Max Planck Institute of Colloids and Interfaces discovered that the white fruits of the characteristic plant balls contain a fibrous adhesive. This is not only water-soluble and biodegradable, but has many other fascinating properties. For example, its adhesive strength can be regulated by the humidity in the air, and the individual fibers can weld together and form three-dimensional structures. A berry could therefore not only contain an adhesive, but also a fiber-reinforced, biological plastic. The Mistelmosterei bridges the gap between research and mistletoe infestation in the orchards. During the Advent season, when the berries are ripe, the Mosterei removes the mistletoe professionally for the owners – and at low cost, as the Mosterei keeps the plants and processes them in its own factory. There, the mistletoe berries are separated from the plants by shaking. Afterwards the berries are washed to remove dirt and plant residues. A specially shaped agitator mixes the berries. The sticky fibers wrap themselves around the agitator, while the pulp, seeds and berry skins remain as sediment. Small impurities are finally combed out. The berry sediment is disposed of and the sticky fibers (viscine) are left behind. This produces the environmentally friendly adhesive “Mistletoe Fix”, which contributes to the preservation of orchards.