Do GMOs have the potential to reduce the population of invasive species?

Expert response from Tony Shelton

Professor

Tuesday, 25/08/2015 14:06

This is a good and complex question! Just so we are on the same page, first let’s define what an invasive species is. A scientific panel has defined it as “a species that is non-native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” An invasive species can be an arthropod, weed, virus or another organism. Your question really focuses on whether a GMO can be used to combat an invasive pest species. Let’s take insects and a virus as examples.

Many pests of our food and fiber crops grown in the United States are really invasive species. For example, the European corn borer (ECB) is not native to the U.S. but came over from Europe in the early 1900s and annually causes more than $1 billion in damage to the corn crop, as well as losses to apples, beans, various cereal crops and potatoes. When ECB attacks corn it bores into the stalk, causing the plant to fall over, or the ear, reducing crop yield or causing the ear to rot. In 1996 corn that was genetically engineered to express proteins from a common soil bacterium, Bacillus thuringiensis (Bt), was first commercialized. The proteins expressed in Bt corn for control of ECB are virtually the same as those sprayed by organic growers. Same proteins, just a different delivery system. Decades of studies have demonstrated that these proteins are safe to humans and the environment.

In 2015 in the U.S. more than 80 percent of the field corn grown was Bt corn and it does a remarkable job of controlling this invasive species. In fact, studies conducted in the U.S. corn belt have shown that Bt corn has suppressed populations of ECB so effectively that it is no longer a pest species in many parts of the Midwest. The same situation has occurred with Bt cotton which is grown on approximately 90 percent of the U.S. cotton acreage and has nearly eliminated an invasive species from Asia, the pink bollworm. 

Another example of a GM crop fighting an invasive species is papaya. In Hawaii, a strain of the papaya ringspot virus (PRSV) decimated papaya production in Hawaii in the 1990s. The virus is an invasive species that is transmitted by aphids that feed on an infected plant and pick up the virus in a matter of seconds. The aphid then flies to a healthy papaya, starts feeding and infects the plant. Infected plants produce unmarketable fruit and die. Spraying for aphids is ineffective and not a suitable strategy.

Scientists were able to take part of the virus particle and engineered it into papaya, thereby making it resistant to PRSV infection. It is analogous to having a human vaccinated. First introduced into Hawaii in 1998, now more than 80 percent of all the papaya produced in Hawaii is GM.

These are just a few examples of how GM plants have been used to control invasive pest species in a safe and sustainable manner. However, more needs to be done because the number of invasive pest species is growing exponentially due to increased global trade. 

Expert response from Tony Shelton

Professor

Tuesday, 25/08/2015 14:06

This is a good and complex question! Just so we are on the same page, first let’s define what an invasive species is. A scientific panel has defined it as “a species that is non-native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” An invasive species can be an arthropod, weed, virus or another organism. Your question really focuses on whether a GMO can be used to combat an invasive pest species. Let’s take insects and a virus as examples.

Many pests of our food and fiber crops grown in the United States are really invasive species. For example, the European corn borer (ECB) is not native to the U.S. but came over from Europe in the early 1900s and annually causes more than $1 billion in damage to the corn crop, as well as losses to apples, beans, various cereal crops and potatoes. When ECB attacks corn it bores into the stalk, causing the plant to fall over, or the ear, reducing crop yield or causing the ear to rot. In 1996 corn that was genetically engineered to express proteins from a common soil bacterium, Bacillus thuringiensis (Bt), was first commercialized. The proteins expressed in Bt corn for control of ECB are virtually the same as those sprayed by organic growers. Same proteins, just a different delivery system. Decades of studies have demonstrated that these proteins are safe to humans and the environment.

In 2015 in the U.S. more than 80 percent of the field corn grown was Bt corn and it does a remarkable job of controlling this invasive species. In fact, studies conducted in the U.S. corn belt have shown that Bt corn has suppressed populations of ECB so effectively that it is no longer a pest species in many parts of the Midwest. The same situation has occurred with Bt cotton which is grown on approximately 90 percent of the U.S. cotton acreage and has nearly eliminated an invasive species from Asia, the pink bollworm. 

Another example of a GM crop fighting an invasive species is papaya. In Hawaii, a strain of the papaya ringspot virus (PRSV) decimated papaya production in Hawaii in the 1990s. The virus is an invasive species that is transmitted by aphids that feed on an infected plant and pick up the virus in a matter of seconds. The aphid then flies to a healthy papaya, starts feeding and infects the plant. Infected plants produce unmarketable fruit and die. Spraying for aphids is ineffective and not a suitable strategy.

Scientists were able to take part of the virus particle and engineered it into papaya, thereby making it resistant to PRSV infection. It is analogous to having a human vaccinated. First introduced into Hawaii in 1998, now more than 80 percent of all the papaya produced in Hawaii is GM.

These are just a few examples of how GM plants have been used to control invasive pest species in a safe and sustainable manner. However, more needs to be done because the number of invasive pest species is growing exponentially due to increased global trade.