By Henrylito D. Tacio
A liability can be an asset if you have the knowledge on how to do it. Such is the case of golden apple snail or golden kuhol (scientific name: Pomacea canaliculata), one of the pests that attack rice during its growing stage.
In his Facebook post, former Agriculture Secretary Emmanuel Piñol cited a study conducted by Rocky French, a Filipino-American farmer scientist who has a farm in Coachella Valley in Southern California. In his 36-year study on the characteristics and benefits of the golden kuhol, he found that the gastropod can produce nitrates, a natural form of the commercial urea.
“The study may change the golden kuhol’s image from farm pest to farmers’ friend,” Piñol wrote, adding that French “has perfected the process of producing natural nitrates from the excrements of the golden kuhol kept in a tub with water and fed with malunggay leaves.”
French told Piñol, who had visited the farm, he considered the pesky golden kuhol as “beautiful animals” as they “could not be used in producing natural nitrates needed by farmers in the face of skyrocketing prices of commercial fertilizer.”
In a research we conducted, we found out that the meat and shells of golden kuhol contain vitamins, protein, fat, carbohydrates, calcium and other nutrients which can be absorbed by crops. As such, it is suitable for the manufacture of liquid organic fertilizer (LOF).
Studies have shown that LOF from snails can help restore and improve soil fertility. It also improves crop production and the quality of growth in plants. The nutrient contents of LOF are quickly absorbed by crops.
A study was conducted on the effects of bio-extract fertilizer from golden kuhol on rice. The experiment used the fertilizer at different concentrations. These were spread on paddy sprouts through leaves and stems every 7 days until the rice grew and paddies became milk rice. It was found that the use of fertilizer at 25 mL/20 liter of water was the best.
In terms of the height of paddy sprouts after spraying for 2 and 6 weeks, it was found that the use at 20 mL/20 liter of water is the best. As for the tillers, there was no difference in any concentrations used after fertilizer spraying for two weeks.
In another study, the application of 30 liters per hectare of the experimental LOF gives the highest yield of tomato.
These findings are indeed good news for farmers. Aside from beating the high cost of commercial fertilizers, using golden kuhol as a source of organic fertilizer can also help in getting rid of the pesky gastropods.
The golden kuhol belongs to an animal species that had existed for 500 million years. It was first introduced to the Philippines between 1982 and 1984 as an additional source of food and protein for Filipinos.
“(Golden kuhol) was the more prolific version of the local snail, called igi or susu which we cooked with coconut milk or gata, young bamboo shoots or labong and saluyot was considered a gourmet food for Filipino families,” Piñol said.
Unfortunately, the snails were not welcomed much by Filipino consumers. Although they were initially expensive at first, their market value soon plummeted. As a result, they were left unattended.
Some escaped while others were completely discarded. Soon, they quickly spread through waterways and irrigation canals. When they reached the rice fields, they found an ideal habitat, feeding by night and at dawn on young succulent plants such as newly transplanted rice crops and weeds.
“With only a few natural enemies to constrain them, the snails rapidly developed into a serious pest in many areas of cultivated rice lands,” the Food and Agriculture Organization (FAO) of the United Nations reported.
When infestation is severe, farmers can completely lose their rice crops if they don’t control the pest effectively. “The snails are living machines that eat and grow incessantly. They can gobble up a hectare of rice seedlings in hours,” deplored Jethro Adang, the director of the Davao-based Mindanao Baptist Rural Life Center.
FAO estimated that yield losses owing to this pest ranged from 1% to 40% of the planted area in the Philippines, resulting in huge production loss.
“To control the snails is difficult and costly,” said Zubir Bidin of the Department of Agriculture in Malaysia. “The snails are prolific, and females may lay 2000 – 3000 eggs in one year. No natural predator is known, and the use of pesticides may kill other types of beneficial snails and aquatic organisms.”
In the Philippines, many farmers apply synthetic molluscicides that are expensive and broad spectrum to get rid of the snails. The bad thing about this is that these pesticides also affect non-target organisms including human beings. In 1990 alone, P212 million was spent to control the rice pest.
Today, golden kuhol is still a rice pest. But farmers have learned some ways to obliterate them. In a paper published in the International Journal of Scientific and Technology Research, several techniques were cited.
For one, farmers can fetch the golden kuhol directly by hand from the fields in the morning and afternoon when the golden kuhol is active and easy to take. Or they can use plants that contain toxins for the golden kuhol. For instance, the leaves of water hyacinth, tobacco, calamansi, and red peppers contain ingredients that can kill the golden kuhol.
Another method is using attractants such as taro leaves, banana leaf, papaya leaves and old newspapers, to easily collect the golden kuhol.
Still another: Preventing field entry. In areas where water enters and exits, a barrier may be placed. A wire or woven bamboo screen or mesh bag may be placed on the main irrigation water inlet and outlet to prevent snail entry.
Golden kuhol can also be controlled by allowing ducks to graze during the growing stage of rice. In a study, continuous grazing for a period of 1-2 months significantly reduced the pest density.