Potato blight, caused by the water mold Phytophthora infestans, causes significant losses to potato farmers worldwide. Farmers resort to spraying their crops with fungicides on a weekly basis to control the disease. A study conducted by a team of scientists from Wageningen University & Research and Teagasc—the Irish Agriculture and Food Development Authority—suggests that a potato variety genetically engineered to resist potato blight can help reduce the use of chemical fungicides by up to 90%. The approach uses two tools: a genetically modified (GM) potato along with a new integrated pest management (IPM) strategy.
The international team of scientists developed the IPM2.0 approach which involves growing blight-resistant potato crops and monitoring an active pathogen population and a “do not spray unless” fungicide use strategy. This strategy means farmers will not apply fungicides unless a potato variety is at risk by a pathogen. The team tested their strategy over several years in potato-growing countries Ireland and the Netherlands using three potato varieties: a susceptible variety called Désirée, resistant variety Sarpo Mira, and a resistant version of the Désirée that received a
resistance gene from a wild relative through cisgenesis.
The susceptible potato variety and the two resistant ones were cultivated comparing common practice, with fungicides applied on a weekly basis, and the IPM2.0 method. The IPM2.0 strategy on the susceptible variety Désirée, resulted in an average reduction of 15% on the fungicide input. Both resistant varieties, however, remained healthy with an average 80%–90% reduction of the fungicide input.