Residual and systemic activity plus stronger potency will soon be available.
Plants have manufactured their own pesticides to protect against insect invaders for millenia. Contained within the essential oils of the plant, these complex molecules have unique modes of action (at least four have been identified) that make them a valuable tool in the arsenal of crop protection products. Besides acute toxicity, lifecycle disruption and repellency, these oils offer growers operational benefits such as zero worker reentry interval (REI), zero pre-harvest interval (PHI) and zero maximum residue levels (MRLs). The only disadvantage is they dissipate fairly quickly, without the long residual or systemic activity of some traditional chemistries.
This is about to change. KeyPlex has long been a leader in the development of nutritional and botanical oils. The company has invested in developing a new generation of botanical oils that are not only more potent, but also offer strong residual activity.
“We actually designed and constructed new molecules that are just slightly modified from the natural ones,” says Gerald O’Connor, President of KeyPlex. “They are far more biologically active than current botanical technologies. This is a major breakthrough!”
Researchers at KeyPlex used their deep understanding of the compounds within botanical oils, gained from two decades of research, to dive even deeper into how they work.
“What really allowed us to go to this next level was our analysis of what molecular structure has to be in place for the insecticidal activity in that mode of action to exist,” O’Connor says. “This is something no one had ever done before with plant essential oils.”
Small Changes Yield Big Results
Armed with this information, researchers were able to work on improving the insecticidal activity of each of those molecular structures. By modifying the compounds just slightly, they were able to have a big impact on efficacy and residual activity.
The main reason for the increased potency is the modified molecules are quite good at penetrating the insect’s cuticle. They also last longer once inside, enabling the active ingredient to reach the target site in the pest.
“We’re taking the pure constituents out of naturally occurring compounds – including some KeyPlex is already selling – and derivatizing them in the lab,” says Murray Isman, Professor Emeritus of Entomology and Toxicology at the University of British Columbia. “They’re chemically modified, but not in a huge way. They very closely resemble the natural substance, or in some cases might break down inside an insect or plant into the original natural substance. In that case, the derivatized or modified form just becomes a vehicle to get the original chemical inside the organism you are trying to kill or manipulate.”
Not only is the derivatized molecule able to get into the target organism more quickly, it stays there longer, too. Isman says derivatives can be more resistant to the enzymes in the insect that normally break down pesticides, meaning higher potency and longer residual effects.
“You can get a big impact with some pretty subtle chemical modifications,” Isman says.
New Botanical Technology Will Have Residual and Systemic Activity
One of the reasons plant essential oils are so often used for flavor and fragrance is they start to evaporate and volatilize as soon as you apply them.
“This is great for a safety and toxicology profile, because they disappear quickly, but its challenging in the crop protection market where you want to get 10, 14, maybe 30 days of control,” Bessette says. “We bonded two natural compounds together to tie them up chemically. They have no fragrance, and they are only released once Mother Nature or the insect’s metabolism breaks them down.”
Some of the new technologies are actually systemic in plants, moving through the vascular system after the spray application. Normally, because many essential oils are fatty or oily substances, they don’t move very well in the plant. KeyPlex made water-soluble molecules that can move systemically within the plant.
A key advantage of botanical oils is that the numerous and complex compounds make development of resistance in the insect population nearly impossible. Resistance has become a big issue for single-molecule synthetic chemistries such as pyrethroids. Asked if KeyPlex would be going down this same path with the new botanical chemistries, O’Connor says no.
“There’s always a chance that when you use single molecules, resistance can develop,” he says. “But we’re not planning to use a single molecule. We’re always going to blend at least two together.”
Exciting New Products Are in the Pipeline
Isman says the first product with the new technology will likely be available in two to three years; it is going through the U.S. EPA and European Food Safety Authority registration processes right now. He expects up to half a dozen new products will follow in the next four to five years.
“KeyPlex is making the argument that these products are so close to being the natural substance, and they release the natural substance inside the plant or insect that they should be considered as if they are a natural biochemical,” Isman says.
Both Isman and O’Connor are excited about the future of botanical products.
“We have an excellent chemical platform that allows us to make slightly modified molecules from which we can screen and select,” Isman says. “We have more than 50 or 60 new chemicals that are modified on a natural parent. We’ve selected the best five or six to explore and produce larger quantities to take into the field for trials.”
It’s not a moment too soon for growers dealing with an ever-increasing number of pests and an ever-decreasing number of pesticides. The new products are targeting the old enemies — thrips, aphids, mites and whiteflies — and the new, such as brown marmorated stinkbug and spotted wing drosophila.
“Globally, biopesticides are the future,” O’Connor says. “These new products are much hotter than other botanical oils, so we’re really hoping they will be the valuable tool growers are seeking.”