In 1820, the German professor C. F. Eichhorn found a beautiful blue flower in Brazil. It was a river (water) hyacinth (aka Eichornia excellent), which later, due to its massive invasive distribution, became known as the "blue plague."
Invasive species - animals or plants that were accidentally introduced by humans (or spread along man-made corridors) into regions new for them, where they successfully take root, begin to multiply and conquer new territories.
The peculiarity of this plant was that it could live either in water or on wet soil. The stem of the river hyacinth is a kind of sponge that retains air bubbles and allows the plant to stay afloat in the water.
The reproductive rate of the blue flower is amazingly fast. In a year, just one cutting can give more than 100 thousand shoots, that is, if a river hyacinth enters a reservoir, then in the very near future a dense "carpet" of stems and roots will form here.
A person can even walk on this "carpet". The negative effect of such a phenomenon is obvious: the reservoir will become unnavigable, fish will die, because they will not have enough air. However, people do not always think about such dangers.
The publicist N. Nepomniachtchi tells the following story. In 1884, river hyacinth was featured as an exhibit at a large flower show in New Orleans. Here he was seen by a certain woman who really liked a truly beautiful and, moreover, a flower unknown to her.
He was actually good: his petals were pale blue and lavender. The woman took three sprouts and planted them in the pond of her estate near St. Augustine. After a while, the pond turned into a beautiful floral carpet.
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The lady decided that everyone would like it and threw some plants into the St. John's River to delight people with beautiful flowers.
Several years passed, and the river hyacinth grew greatly. As a result, a large expanse of rivers and canals in Florida is covered with a strong tangle of plants. This significantly interfered with shipping. Naturally, various measures were taken to destroy the flower. But the results were the most deplorable. To combat the harmful plant, soldiers were called in to pluck the river hyacinth and cut it into small pieces.
Water hyacinth has become a real nightmare for water bodies in the United States, the plant clogs water bodies, blocks waterways, pumps and infrastructure, it negatively affects water quality, provokes the death of fish and affects fisheries, increases the level of human and animal diseases.
They tried to destroy the plant with dynamite, which, however, gave the opposite effect. During the explosion, scraps of river hyacinth scattered over long distances, as a result of which it "captured" new territories.
Poisonous arsenic began to be thrown into the Mississippi. This killed not only the hyacinth, but also other river inhabitants: fish, birds and other animals. But such extreme measures have yielded at least some results in the fight against the "blue plague". However, after a few months, river hyacinth returned to the Mississippi from canals, ponds and small rivers. And the fight with the flower began again.
After World War II, river hyacinths began to be poisoned with chemical agents, despite the harm they caused to the surrounding flora and fauna. However, as soon as the effect of herbicides ceased, the tenacious plant began to multiply again.
The "stubborn" Brazilian flower has spread beyond America. He also appeared in Australia, where he was obviously brought by a man inspired by the beauty of an exotic plant. Then the river hyacinth ended up in Indonesia, Indochina, West Bengal, China, Africa and Madagascar.
River hyacinth has not become a disaster everywhere. The Chinese and Vietnamese, for example, began to specially breed river hyacinth and feed them to pigs. The floating blue pastures were also very popular with the buffaloes.
In Africa, a ban was issued on the cultivation of river hyacinth, but underground traders, contrary to the ban, cultivated it. A few years later, in Africa, river hyacinth grew so much that in Sudan, entire fishing villages were forced to move to a new place.
Residents of Sudan were the first to complain about the dominance of this plant to a special UN organization dealing with food and agriculture, after which a general campaign to eradicate the "blue plague" began.
The famous Indian chemist Rao went to the lower Amazon to study insects that "graze" on river hyacinths, in the hope of finding one that could stop the growth of plants. Indeed, at home, Eichornia is not considered a "blue plague". Alas, the expedition was not crowned with success.
In Florida, they tried to attract manatees to the fight against river hyacinth. They liked the flowers very much, but there are too few manatees to fully combat the plant.
But a professor at the Paris Museum of Natural History Portes argued that you just need to wait, and not fight the river hyacinth: the biological balance will be restored sooner or later. It is possible that he was right: After about twenty years, the mass invasion of the river hyacinth almost stopped.
However, in the USA they were sure that this was the merit of the advanced methods of their scientists. In the 1970s, flocks of three species of weevils were released to control water hyacinth in the reservoirs of Louisiana, Florida and Texas, which feed only on this plant. After 10 years, scientists enthusiastically reported that the fields of hyacinths had decreased by 33%.
In 2010, scientists repeated the experiment, this time releasing an insect of the species Megamelus scutellaris. Since then, there have been no new data on the control of water hyacinth or a count of the effectiveness of this method.