Simple fix for Vietnam crops cuts pesticide use, sends bugs packing

The Feed the Future Innovation Lab for Integrated Pest Management, housed at Virginia Tech, employs three surprisingly simple materials in the effort — paper wax bags, plastic mesh bags, and plastic sleeves.

These items, which you might find in your kitchen cabinet, can help protect fruits that seem exotic to Americans but are commonplace in Vietnam: mango, longan, and dragon fruit.

Innovation Lab Director Muni Muniappan said the fruits, despite their high export potential to the United States, have not yet reached many international markets with ease. Even when the fruits are shipped, they often don’t make it to consumers. For example, farmers in Vietnam control a common fungal disease with fungicide, which results in shipments to the U.S. being refused when high traces of chemical residues are detected, Muniappan said.

John Bowman, program area leader and senior agriculture adviser at the United States Agency for International Development (USAID), which funds the Innovation Lab, said that it’s crucial to make fruit safer to eat and more profitable for small farmers.

“Agro-chemicals can often play an important role in an integrated pest management program, especially where trade and quarantine pests are involved,” he said. “However, by creating a farmer-friendly, low-cost physical barrier around the fruit, we can reduce the incidence of insect pests and diseases, thus lessening chemical pesticides, production costs, and the risk of a pesticide residue issue that could cripple an economic export opportunity.”

In June 2018, members of the Innovation Lab team traveled to southern Vietnam to assess the effectiveness of the materials and gain a sense for major farmer concerns. Pesticide use was atop the farmers’ list.

Pesticides kill more than bad bugs. They also eliminate beneficial insects, damage surrounding ecosystems, and kill hundreds of thousands of people every year, many of them children. Chemical residues and poor sanitation are the most common reasons imported fruit and vegetable shipments are refused.

The Innovation Lab’s partner in Vietnam, the Southern Horticultural Research Institute (SOFRI), has issued early reports of success:

• Mango bagging has increased fruit yield by thousands of pounds.
• Dragon fruit sleeving has cut chemical sprays up to seven cycles as well as increased marketable fruit by up to 30 percent.
• Longan bagging has caused as much as a 7.08 percent increase in profit.

Nguyen Van Thanh, a mango farmer in Vietnam, said that 90 percent of the farmers he knows overuse pesticides to rid their crops of pests such as stink bugs and fruit flies, as well as a range of diseases. Bagging requires Thanh to hire workers to climb ladders to the tops of 130-foot-tall trees, but he said the labor is worth it.

“I am so thankful for what my orchard has developed into,” Thanh said. “It’s much easier for me to sell my products since I’m using less spray.”

The bags cost less than a penny and are reusable. This keeps the intervention affordable for Thanh, who said bagging keeps fruit clean until harvest and reduces chemical spraying by two cycles.

Prospects for bagging and sleeving technologies in developing nations are promising, Muniappan said, especially for Vietnam, a country that has seen major economic growth in recent years. Efforts to improve the consistency, quality, and safety of food in Vietnam is yet another step toward a food secure world, Muniappan said.

“Low-cost materials like bags and sleeves could easily be implemented across Vietnam and elsewhere as long as farmers and farm workers are willing to look beyond the quick fix of pesticide use,” Muniappan said.

The Innovation Lab is a project of the Center for International Research, Education, and Development, part of Outreach and International Affairs. Current projects include successfully tracking invasive tomato pests through the trade and movement of domestic markets in Nepal, among others.