A new study has revealed the environmental and economic benefits of using insect-resistant genetically modified (GM) corn in Spain and Portugal, the two largest countries in the Iberian Peninsula. Author Graham Brookes used 21 years' worth of data to assess the impact of this GM food. The findings are now published in the journal GM Crops & Food.

The GM crop is resistant to two particular bugs, the European corn borer and the Mediterranean stem borer, two moths whose larvae feed on the whorl and stem of the corn respectively. The Mediterranean stem borer is one of the most damaging pests for corn, which is why some farmers have begun to use corn that is resistant to these insects. 

In 2018, 121,000 hectares of GM corn was planted in the Iberian Peninsula, corresponding to around 35 percent of the total corn area of Spain and about 6 percent of the total cultivation of maize in Portugal. Brookes estimates that the GM crop has led to a 37 percent decrease in the use of insecticides by farmers. In total, that is roughly 678,000 kilograms (1,494,700 pounds) worth of bug-killing active ingredients that have not been used in those fields. The reduction in insecticide use also led to modest savings in water and fuel.

The switch to GM seeds has benefited the farmers economically because the GM corn fields have produced more plants. Over the respective period of adoption, the average yield has increased by 11.5 percent in Spain and 12.5 percent in Portugal.

However, it must be stated that accessing the genetically engineered seeds is more expensive and that the supply chain from the GM technology provider to the farmer has several steps, each with its own cost. About 17 percent of the gains from the technology cover those costs.

The increased yield has added 1.89 million tonnes of corn to production since 1998. This fact is an overlap with the environmental and economic benefits, as the extra corn means a reduction in pressure on farmers to use extra land.

Despite general mistrust for genetically modified crops, GM foods available on international markets "are not likely to present risks to human health," according to the WHO. It is also important to remember that GM food is a vast umbrella term and that the food on your plate is assessed on a case-by-case basis. The use and distribution of these crops remain regulated to try to ensure no engineered genes escape into wild populations.