Mistletoe threatens trees in São Paulo – 07/18/2023 – Daily life

On a sunny weekend, Ibirapuera Park received the usual crowd of visitors looking for a few hours of leisure and rest. Among them was businesswoman Rosângela Pereira, 33, who, taking a break from her morning workout, had her eyes drawn to a tree very close to the Planetarium.

“What an exuberant beauty!”, she said, not noticing that, even without losing her haughtiness, the mulberry tree was camouflaged in its trunk with a silent enemy that plagues the city: the mistletoe. Gradually, if not removed, this parasitic plant feeds on its host, and may even lead to death.

In Ibirapuera Park, one of the postcards of São Paulo, it is estimated that around 100 of the 16,000 trees are affected by this parasite. These numbers are just a preview of the park’s arboreal inventory, whose completion is scheduled for October this year.

“It sounds like they’re talking like it’s some kind of Covid among the trees,” shares Samuel Lloyd, 41, director of Urbia, the concessionaire responsible for managing the park. “At Ibirapuera, we are dealing with a natural environment that favors the propagation of this parasite, however, we have the situation under control.”

About 60 experts in the field — biologists and agronomists — are in action, carrying out strategic pruning to contain the spread of mistletoe. The director, however, makes an important caveat: “It’s no use just for us to carry out the control if the city doesn’t cooperate. This is a collective work”.

Experts say they believe that the spread of this parasite occurred during the process of urban acceleration in São Paulo for at least 60 years.

With parasitic characteristics and a dominant presence in relation to other species of plants and trees, the mistletoe lodges in the trunk, sucking all the vital nutrients and sap from the host plant. This, let’s say, relentless action can lead to the death of the host, which withers due to the shortage of nutrients. To avoid this outcome, it must be promptly combated.

Faced with the limitation of natural diversity planted in streets, avenues and even in homes, as well as in abandoned land, the weed found a fertile environment to proliferate.

One of the regions most affected by the spread of mistletoe is the neighborhood of Higienópolis, on the west side of the capital, says biologist Juliana Summa, 48, coordinator of park management and biodiversity at the Municipal Secretariat for Green and the Environment. The area, which is heavily wooded, has already been the target of government actions to try to curb the spread of the parasite.

It is not new that this weed, also known as bird, visa or manure-of-jurema, has been climbing the trees of São Paulo. At the beginning of this month, the subject came up in a meeting regarding the concession of the Ibirapuera park between representatives of the TCM (Municipal Audit Court), the Municipal Secretariat for Green and the Environment and the Urbia concessionaire.

In Ibirapuera, control of this plant is strategically carried out in this season, in order to avoid disturbances in the period of mating and rearing of young birds. This green oasis in the heart of the country’s largest city is estimated to be home to at least 120 species of birds.

During the months of September to April, activities to combat the parasite are suspended. The park’s technical management team, made up of agronomists and biologists, avoids intervention so as not to affect the reproduction process of the birds.

“Here, we give priority to the reproduction of birds, especially since the park serves as a place of passage and reproduction for migratory species”, explains Lloyd. This approach tries to respect the natural cycle of life and reproduction of birds, contributing to preserve and promote the diversity of species in the park’s environment.

Birds, especially some small species, have the habit of using the robust branches of the weed as a basis for building nests. In Ibirapuera, where more than 500 species of trees can be found, the plants most targeted by the parasite are mainly mulberry trees, myrtles, certain types of palm trees, resedas and privets.

“We carry out manual pruning and there are rarely cases of suppression”, explains the director of Urbia, adding that “the visitors to the park have an affective bond with the trees”. He explains that the work is very meticulous: “Even the disposal of residues resulting from pruning requires special care to avoid the spread of the parasite”.

The entire operation is carried out based on reports that are sent to the Municipal Secretariat for Green and the Environment, as informed by Urbia. “The process is monitored and conducted in accordance with the criteria established by the concession”, adds Llyod. It is important to point out that management guidelines are provided for in the master plan for public parks in São Paulo.

According to the evaluation of the director of Urbia, the issue of the parasite requires the involvement of several actors, including the public and private sectors, NGOs, the population, universities and research centers. It is necessary to unite efforts in a collective attempt to control the spread of the weed and prevent it from spreading further across the city.

According to biologist Juliana Summa, there is no doubt that the lack of natural diversity plays a crucial role in the spread of the parasite, which highlights the importance of preserving biodiversity in parks, providing a balanced and conducive environment for plant and animal life. .

She points out, however, that control should not be limited to public parks. It also needs to be extended to residential areas. “It is essential to carry out control measures both in public areas and in homes and land”, warns Juliana.

It is known that it is impossible to completely eradicate mistletoe, due to its rapid growth and dispersal by birds. However, continuous monitoring measures, pruning and, in more serious situations, removing the tree are necessary actions to prevent it from becoming, in fact, an uncontrolled pest.

The Municipal Secretariat for Green and the Environment, together with which Juliana Summa works, has been carrying out an initiative to make the citizens of São Paulo aware of the presence of mistletoe. This action includes sharing information and alerts about the parasite through social networks.

To get rid of the weed, however, it looks like we need a lot more.