Although only an 11th–grade student, Nguyễn Duy Tân has come up with an innovative and environmentally friendly idea: using weaver ants to control pests on coffee trees. His project not only protects the environment but also shows strong potential for real–world application.
Tân, a student at Lộc Phát High School in Bảo Lộc (Lâm Đồng Province), began his experiment after watching TV programs showing how farmers in the Mekong Delta raise weaver ants to protect fruit trees—especially citrus crops like durian, mangosteen, and jackfruit—from pests. He wondered whether weaver ants could also protect coffee trees. In his area, coffee is widely grown and most farmers rely heavily on chemical pesticides, which both pollute the environment and increase production costs. That inspired him to test whether raising weaver ants could be a natural pest–control solution for coffee farms.
Starting early in the year and completing his work by the end of 2013, Tân and his advisor, teacher Phạm Thị Giang, first researched the ants’ feeding habits, life cycle, and growth needs in the school library. With this theoretical background, he began practical experiments.
His first trial was to raise weaver ants in a container with soil and offer them common coffee pests as food. Surprisingly, the ants ignored the pests and escaped. To prevent this, Tân placed the container inside a basin of water, effectively isolating the ants. As the days passed, the pests inside the container were steadily consumed. “Weaver ants are omnivorous and can eat all kinds of insects,” he explained. “So if they are raised on coffee trees, they can control harmful pests.”
Tân then tested the idea on three local coffee gardens in the hamlets of Thanh Xuân 1, Thanh Hương 1, and Tân Hương 1 (Lộc Thanh commune). These gardens represented different cultivation methods: coffee intercropped with other plants, coffee grown as a monocrop with free–growing branches, and coffee with topped branches. Each site had serious pest problems, and Tân convinced the owners to let him introduce weaver ants.
On 1,000 square meters in each garden, he released ants on half of the area and left the other half as a control. He collected ant nests from the wild and carefully tied ropes between coffee trees so the ants could expand their colonies. To help them settle, he initially provided food—pig and chicken offal—hung on the coffee trees.
After nearly a year of monitoring, Tân found that coffee yields stayed the same, but the number of pesticide sprayings dropped by 50–66%, cutting costs by about 2 million VND per hectare per year (roughly 100,000 VND per 500 m²).
“The clearest success was in the monoculture coffee garden,” Tân concluded. “There, 60–80% of the trees hosted weaver ants, and pest damage was dramatically reduced.”
However, there was one drawback: the ants bite during coffee harvesting. To overcome this, Tân suggested that farmers harvest in the early morning or late afternoon, when ants remain in their nests, or cut down the branches containing ant nests during picking and let the ants climb back after harvest. In the dry season, when insect prey is scarce, farmers should also supplement the ants’ food to maintain the colony.
Among the five gardens where he tested the idea, three have kept the ant colonies after seeing the benefits.
Principal Nguyễn Hoàng Chương praised Tân’s project as “highly practical and environmentally friendly, perfectly suited to the local coffee–growing region.” The school is now encouraging Tân to refine his method and enter higher–level science competitions.
Despite his personal hardships—his mother passed away, and his father works far from home—Tân remains a top student and actively participates in school activities. The school provides him with monthly scholarships to support his education, helping him continue his promising scientific work.