9.2.3. Mistletoe — friend or foe?

Mistletoe is a symptom of declining eucalypt health, rather than being the cause of a tree to decline. It is usually more prevalent in isolated paddock trees.
Mistletoes are partial parasites which obtain mineral nutrients and water from the host plant. Many parasites have co-evolved with the Australian flora and fauna and mimic their host plants. You will find them attached to a wide range of species including eucalypt, acacia, casuarina, banksia and introduced trees.
Parasites and pathogens are likely to take advantage when plants are stressed by other factors such as changed soil nutrient status, soil compaction, salinity, fertiliser use, and insect or fungal attack.
Research has concluded that mistletoe may kill plants outright, but they more often die from a combination of stresses.
On the other hand, mistletoe is also a vital part of the food chain in our ecosystems, as all parts of this parasite are eaten by native wildlife.
Flowers and nectar from the mistletoe offer a reliable food source for many species of birds and its berries are the main food of the Mistletoe Bird and some honeyeaters.
Parrots such as rosellas act as natural control agents of mistletoe because they eat copious amounts of berries but, unlike the Mistletoe Bird, they do not pass the embryonic seed in the berries in their droppings.
Leafy mistletoes are favoured food plants of various marsupial species such as the Brushtail and Ringtail possums. Butterflies also rely on mistletoe for food.
Pruning is the only reliable short-term control measure where mistletoe appears to be getting out of hand.
In the long term, eradication is not desirable because of its importance to native fauna.
Source: Excerpted from Greenote 18, produced by Greening Australia

Include a photo of a tree with mistletoe