Pests with potential

THE LONG-CONSIDERED “decorations” that thrive all over the world pestered residents of Cotabato City last month by invading the waterways of Rio Grande de Mindanao causing knee-high floods in the recent ‘Falcon’ onslaught.

While public officials declared an ecological battle against these plants, some Filipinos remain hopeful of their potentials and tapped their innovative characteristics.

Water hyacinth (Eichhornia crassipes), erroneously called as water lily, is a free-floating plant, naturally growing in tropical freshwater bodies that originated in South America.

The plant was initially cultivated as ornaments because of its lovely rounded lily pads and eye catching white-to-lavender lilies, but today, it is also considered as a “pest” that needs to be eliminated.

Biology professor Rosie Madulid from the College of Science said this plant multiplies fast and it can easily cover a water area in a short period of time.

Studies show that this aquatic plant can spread from 10 to 600,000 pieces in only eight months.

Water hyacinths do not initially cause a problem. In fact, studies have shown that they are good natural habitats for aquatic animals, Madulid said.

Its abnormal rate of proliferation, however, has caused it to become a nuisance, and thus called a “weed.”

“This is bad for other aquatic plants [around the area]. They shade the water from the sun, creating an imbalance in the water ecosystem, to the extent that they are diminishing oxygen supply to living things,” Madulid said.

The aquatic plants in the area, like ferns, seaweeds, algae and the like, do not get enough sunlight for photosynthesis (a process converting sunlight into energy and acquiring oxygen), which thus kills them and eventually the fishes.

These aquatic organisms, thus, have difficulty in surviving, causing an imbalance in the ecosystem.

Moreover, the rapid reproduction of water hyacinths forms a “barrage” that obstructs fishing and irrigation by blocking canals and waterways, causing damages and floods similar to what happened in Cotabato City.

However, there are three well-known treatments for these problems: physical, biological, and chemical control.

Madulid said physical control is done by removing the plants entirely from the water.

Physical control is widely used, but it is expensive and does not work well in very large infestations. Like the situations in Philippine rivers, these plants grow back as quickly as they are uprooted.

Biological control, on the other hand, uses insects and fungi to reduce the weeds population.

“They seed insects to the water hyacinths and these insects will eat the plants reducing their number,” Madulid said.

This process, however, is only preliminary and needs to be examined further, she added.

Finally, chemical control, the least popular among the three is basically done by applying aquatic herbicides. Studies show that this is fast, effective and less expensive in managing water hyacinths.

But Madulid said this method is not advisable because of its long-term toxic effects to plants and animals, and even to humans, immediately close to the area.

Something useful

Though water hyacinths cause nuisances, some communities turned the problem around and made these “invasive plants” useful.

Manulid said water hyacinths are used as bioindicators for metals in the water.

“The floating roots of the plant can accumulate heavy metals like lead in the water. This can be used to test the concentration of metals inside the water which indicates how ‘dirty’ the water is,” she said.

Studies have also shown that these plants are now used as source of biogas fuel. After the incident in Cotabato City, President Benigno Aquino III has shown interest in making these weeds useful by converting them into fuel.

Task Force Mindanao River Basin drafted a plan for the use of water hyacinths in the area as dentro-thermal power source. They will gather these aquatic weeds and use them for the power plant to produce coal briskets.

Moreover, Madulid said parts of the plant have many practical applications. Its stalks and leaves can be used as materials to make slippers, bags, mats, and the like.

Sagana SP2, a non-profit organization composed of mothers in Laguna, devised a process of using water hyacinth stalks as fibers woven into different handicrafts. It is important that the plant is completely dry to prevent molds from developing.

In Las Piñas City, on the other hand, Congresswoman Cynthia Villar, wife of Senator Manny Villar, declared the 27th of July as the day for Water Lily Festival. The community has been annually celebrating the event since 2006.

They make handicrafts out of dried hyacinth stalks from Zapote river and Las Piñas River. This year, she added that they held the first search for Ms. Water Lily where gowns of the contestants were made from water hyacinths, said project manager Vangie Dalosa.