Published on May 5th, 2019 | by Steve Hanley0
Targeting Agricultural Pests Without Pesticides
May 5th, 2019 by Steve Hanley
Nematodes are a type of worm that damages crops. Every year, they cause more than $130 billion in damage to agricultural products. The usual way of controlling them is to dump tons of pesticides on the fields where crops are grown, but that blunderbuss approach also kills many of the insects which are vital to maintaining the health of those same fields.
Gene splicing may have an answer for farmers who want to increase their yields without increasing their use of pesticides. Dr. Konstantin Blyuss, a mathematician at the University of Sussex, has developed a chemical-free way to precisely target a parasitic worm that destroys wheat crops, according to Science Daily. This method of pest control works with the plant’s own genes to kill nematodes without harming any other insects, birds or mammals.
Blyuss has collaborated with biologists at the National Academy of Sciences of Ukraine to test his theories. “With a rising global population needing to be fed and an urgent need to switch from fossil fuels to biofuels, our research is an important step forward in the search for environmentally safe crop protection which doesn’t harm bees or other insects,” he says. The research has been published in the journal Frontiers of Plant Science.
Non-toxic pest control could help feed growing global population, boost organic food production, and drive bio-fuel production. Experiments show up to 92% more crops survive with this approach compared to no pest control.
There are naturally occurring bacteria contained in soil which can help protect plants against harmful nematodes, but until now there has not been an effective way to harness the power of these bacteria to protect crops on a large scale. Blyuss and his colleagues have used a process called RNA interference to precisely target a species of nematode that harms wheat.
How RNA Interference Works
Blyuss explains, “A nematode, as all other living organisms, requires some proteins to be produced to survive and make offspring, and RNA interference is a process which stops, or silences, production of these.” Biostimulants derived from naturally occurring soil bacteria are able to switch off the plant’s own genes that are affected by the nematodes, making it much harder for the parasite to harm the crop. They can be applied either by soaking the seeds or roots in a solution containing the biostimulants or by adding the solution to the soil in which the plants are growing.
“By soaking the seeds of the plant in the solution of biostimulants, the plant becomes a Trojan horse for delivering special compounds produced inside the plants to the nematodes, which then kills them. We’ve targeted the specific genes of the nematode, so we know this won’t affect other creatures,” Blyuss says.
The biostimulants only affect specific nematode and plant genes, and do not harm other species of insects. And because they are naturally occurring, rather than made of chemicals, they could potentially be used by organic farmers to make organic food more affordable in future.
The team’s experiments show that soaking the seeds of the plants in the biostimulant solution increases the chances of the plants surviving by between 57 to 92%. The technique also reduces the level of nematode infestation by 73 to 83% compared to plants grown without biostimulants.
“By using mathematical models, we learned how biostimulants are absorbed by wheat plants, so we now know the best way to deliver them. We’ve also looked at how the RNA develops inside the plants and nematodes, how the plant is able to switch off specific genes involved in the process of nematode parasitism, thus stopping infestation, and how parts of RNA from plants, when ingested by nematodes, cause their death by silencing some of their essential genes.”
These insights were combined with advanced experimental work on developing new strains of soil bacteria and extracting their metabolites, as well as with state-of-the-art molecular genetics analyses, to develop a new generation of environmentally safe tools for control of wheat nematodes.
“Some people are wary of genetically modified plants, so it’s important to be clear that that is not what this is. Biostimulants effectively act as an ‘inoculation’ against nematode infestation. They achieve their effect by mobilising plants’ internal machinery to produce compounds that protect plants against nematodes, while simultaneously causing nematode death.
“The plants produced using biostimulants have much better crop yields and higher resistance to pests, but they are no different from other plants that have been artificially bred to have some useful characteristic. Moreover, the biostimulants themselves are truly natural, as they are nothing else but products of bacteria already living in the soil. “
Professor Dave Goulson from the University of Sussex’s School of Life Sciences, and a global expert on declining bee populations, highlights the importance of this research. “There is growing awareness that the heavy use of conventional pesticides in farming is causing great harm to biodiversity, resulting in pollution of soils and waterways with harmful toxins. We urgently need to find alternative, sustainable means to control crop pests.”
Monsanto, Dow, and other large chemical companies that depend on selling millions of tons of pesticides every year won’t be pleased. Their method is like using a tactical nuclear device to kill a gnat. The approach developed by Dr. Blyuss and his colleagues is more like a surgeon using a scalpel to remove a tumor. The Earth needs more of the Blyuss approach and less of the Monsanto method.