Plants bred to yield better often lose their natural defenses to battle insects, and the question arises would farmers be willing to turn to plant varieties that may yield less but can better defend themselves against insects, lessening the need for insecticides.
In a July 22 virtual forum sponsored by the North Carolina Biotechnology Center, Jeremy Kroemer, agrochemical discovery lead for Bayer Crop Science; and Joseph Stout, BASF group leader, biology, global insecticide research advanced biology and agronomy, said this will be a tough sell because yield is still the name of the game.
“The main thing driving the industry is yield. At the end of the day, the farmer wants a product that works, the farmer wants a product that’s going to bring home the maximum yield,” Kroemer emphasized in the forum for crop scientists.
By and large, Kromer said farmers want clean fields, free of worrisome weeds and insects. He notes that the introduction of Bt (Bacillus thuringiensis) hybrids that are resistant to insects has grown the viewpoint that a clean field is not being impacted by insect damage.
Kroemer says plants with a natural defense to insects will still be touched by and eaten to some extent by insects which will concern farmers looking to improve yields. He says farmers look for visual cues and if they see insect damage, they want to control that damage because the seek to protect the plant entirely.
Kromer says engineered traits that push insects away from the plant and enhance the survivability of plants would interest farmers.
“Let’s say you engineer a plant to be more resistant to insect damage. You add in a trait that causes a feeding deterrent and pushes the animal away and then you retain your stacks of Bt that actually kill the insects. In this case you may be providing a new situation where you are pushing certain animals in the population away from that plant and you’re providing a selective advantage for those animals because they’re not being killed by the Bt that’s retained by the plant,” Kroemer said.
Stout agrees with Kromer and says it all comes down to economics. He says farmers want to control pests, but they also want to reduce insecticide costs. If it is more cost effective to use genetically engineered seed and thereby reduce insecticide costs, farmers will likely go that route.
“There are different insecticides out there. Some of them have a more benign profile to non-target insects. There is some selectivity in some of those. A putative neurotoxin causes paralysis and within a matter of minutes the insect is dead. You also have insecticides that inhibit feeding,” Stout said.
Stout said the benefits must be demonstrated in a competitive way. For example, the pest may still be present in the field, but the damage caused to the crop is reduced. Still, anything that reduces yield and quality will be a difficult sell.
“A big part is the expectation of the end of the end user. There is consumer demand for zero pest presence. That’s an even more difficult sell. For example, head lettuce and table grapes are crops that need to be pristine,” he said.