Ask just about anyone the question, “Are you in favor of reducing pesticide use on crops?” and you will almost certainly get the same answer: Yes! We all want fewer pesticides on our foods. So if we essentially all agree, how do we get there?
For infectious diseases, there are four general approaches to disease management, as follows:
- Genetic resistance: Basically we are taking advantage of the plant’s capacities to defend itself from microorganisms through its own biochemistry.
- Cultural practices: This means that we manage diseases through the way we grow the plant. Examples include crop rotation, using pathogen-free seed, careful management of fertilizer, etc.
- Biological control: This involves taking advantage of living organisms that suppress or destroy the infectious agent of concern.
We already agree we want to eliminate pesticides, so let’s remove that from the discussion. Biological control is wonderful and is active in essentially all agricultural soils. Unfortunately, destructive diseases still occur in cropping systems, so natural biological control is commonly not enough. Cultural practices can be powerful tools for disease control, but like biological control, they are often insufficient.
That leaves genetics, by which I mean “genetic modification” in the broadest sense. I am being highly inclusive, in that I am including the full range of genetic tools for crop improvement, from the most traditional breeding technique known—simple selection—to the most sophisticated, diverse strategies of genetic engineering (GE). Genetic tools offer a wide spectrum of techniques that can provide pesticide-free disease control.
Just a few days ago, an invited review paper of mine was published in the open-access journal, Sustainability. The title is, “Genetic Engineering and Sustainable Crop Disease Management: Opportunities for Case-By-Case Decision-Making.” The content in the paper is quite solid scientifically. It has gone through multiple rounds of peer review, including a university seminar on this topic, to take advantage of the opportunity for peer-review before the outstanding molecular biologists in my department.
The manuscript describes nearly a dozen distinct strategies for engineering disease resistance in plants. Indeed, in preparing the review by reading the relevant scientific literature, I was astounded by the diversity of approaches molecular biologists have for engineering disease-resistant plants. There are many opportunities already, with more coming with each year of rapidly advancing science.
Can genetic engineering really reduce pesticide use? Yes. We know this is true. Bt crops, which are crops engineered to be resistant to certain insects, have consistently provided for reductions in insecticide use around the world. The benefits of these pesticide reductions have included:
- Lower production costs for farmers
- Fewer pesticide poisonings in countries with developing economies
- Increased insect biodiversity
It is important to keep in mind that no single tactic for controlling diseases is “the final answer.” Disease-causing organisms always adapt to whatever we do in the agroecosystem. Thus, we always need to continue to find ways to reduce selection pressure on these organisms, whether we are using GE or not. (See Section 3 of my review paper for more on this topic.) But I see GE as analogous to a cell phone. Yes, there are risks, but there are many benefits. Why not wisely take advantage of useful technologies?
For evidence-based citations in support of the statements made in this post, please see my review paper and the recent report by the National Academy of Science, Genetically Engineered Crops: Experiences and Prospects.