Plants modified to produce molecules which can be easily converted into the sex pheromone of damaging moth species could offer a new, sustainable and inexpensive option to control these pests.
An international team of researchers have found that the seeds of Camelina sativa, a flowering plant sometimes known as false flax, can be genetically-modified to express a fatty acid that can be converted into a sex pheromone which is attractive to the diamondback moth (Plutella xylostella), a prevalent and damaging pest of brassica, and the cotton bollworm (Helicoverpa armigera).
Insect pheromones are widely used in pest management programmes. They can be used to lure and trap individuals, as well as disrupt the mating process by confusing males pursuing females. However, due to their lengthy production process and expensive raw materials resulting in high manufacturing costs, they are most often used by growers of high-value crops such as orchard fruit.
Novel product proves equally attractive to moths
In field trials, traps using the pheromone derived from the genetically-modified plants were used in an experimental field of choy sum (Brassica rapa var. parachinensis) where diamondback moth had previously been observed, alongside traps using conventionally-manufactured pheromones. The experimental pheromones proved equally efficient as the existing lure type for trapping the moths.
Likewise, in a mating disruption experiment targeting the cotton bollworm using both types of pheromone in a field of common dry beans (Phaseolus vulgaris), the novel pheromone was equally effective as the traditionally-manufactured type.
“Together, the results of these field trials suggest that Camelina-derived pheromone could effectively replace petroleum-based synthetic pheromone when formulating pest management products,” explained the scientists.
Such a replacement could improve sustainability credentials while reducing global supply chain pressures, they suggested.
Democratising insect pheromones
The production methods detailed in the research could potentially open the market for pheromone-based crop protection affordable to growers of lower-value crops.
An alternative plant-based approach would be to genetically-modify plant species that can release insect pheromones in the field – however, the team noted that this has yet to be proved successful.
“Camelina, which has high yield potential and oil content and simple genetic transformation methodology, provides an ideal platform for production of moth pheromones,” they added.
Producing inexpensive pheromones using novel biological processes is a growing area of research – with another recent study creating pheromones for moth and fly species derived from yeast.
You can read the full study in Nature Sustainability.
