A simple sheet of plastic is proving to be an effective alternative to expensive, harmful insecticides for controlling a major potato pest.
Researchers at the International Potato Center (CIP) working in the high Andes have discovered that plastic barriers not only help farmers but also protect biodiversity and the environment.
Andean potato weevils (Premnotrypes suturicallus) are a major problem for farmers at altitudes of between 2,800 and 4,200 meters, where potato is an important staple and cash crop. The weevils, which are common at these altitudes, crawl into potato fields at the beginning of the season and breed. After hatching, the larvae move into the soil and feed underground on tubers. To date no crop resistance to the weevil has been detected. Farmers attempt to control weevils mainly by using 2-4 applications of insecticides, which are expensive, highly toxic, and often ineffective due to dosages are wrong or mistimed.
Despite pesticide usage, between 15 to 40% of tubers still get infested. When no control measures are taken, the weevil can destroy more than half of the crop.
But the Andean potato weevil has an Achilles heel: it is flightless.
“Erecting a simple plastic barrier just 30-50 centimeters high and 10 centimeters into the ground is very effective in stopping weevil migration to potato fields and consequently tuber damage,” explained CIP entomologist Jürgen Kroschel. “What’s more, it’s an idea that has been tested collaboratively with local farmers to assess its impact, ease of use and acceptability.”
Under CIP’s integrated pest management program, more than 60 individual field experiments were carried out over 4 years with farmers in the high Andean villages of Ñuñunhuayo and Aymara. The experiments set out to determine the efficiency of plastic barriers, farmer receptivity and the potential economic benefits to farmers.
The results have been positive. Barriers were found to be up to 70 percent more effective than insecticide applications in reducing Andean potato weevil damage. They were tested against other Andean weevil species in locations throughout Peru, Bolivia, and Ecuador and, in all cases, were found to be at least as equally as effective as insecticides.
Photo credit: KV Raman, CIP