Consumer concerns about pollinator health, persistence of chemicals in the environment and the safety of the food we eat are beginning to trickle upwards. Growers are cognizant of customers’ perceptions, whether real or biased, and regulators continue to tighten restrictions on pesticides and labeling. But still, growers need to protect their crops.
“Botanicals are part of the solution,” says Steve Bessette, Vice-President of the Botanicals division at KeyPlex. “The product we offer, Ecotrol, contains botanical active ingredients (peppermint oil, rosemary oil and geraniol), is U.S. EPA exempt and USDA NOP compliant, and utilizes GRAS materials, which nobody else has.” GRAS means Generally Recognized As Safe by the U.S. FDA. It’s a status given to materials where there is a consensus of expert opinion regarding its safety. In the case of these botanical oils, they’re exempted because we’ve been eating them for literally centuries. They’ve been used for medicinal purposes and in the cosmetics and fragrances you use. There is a long history of usage without any adverse effects being noted. People are using them already and exposing themselves to the chemistries at a much greater level than if we are applying them in the agricultural field. Combined with the fact that mammals don’t have the nerve receptors botanicals target, these compounds have a much better safety profile than any conventional synthetic chemistries that are out there.”
“Certain EPA exempt, botanical oils have a zero re-entry interval, zero pre- and post-harvest interval, are exempt from maximum residue levels (MRLs) and quite frankly, have the mode of action people are looking for,” Bessette says. “We invested many years of research to find out why these oils work – why plants have used them for protection for thousands of years. And we found the chemistry of certain essential oil compounds is nearly identical to the chemistry of the neurotransmitter, octopamine, present only in invertebrates. The KeyPlex botanical oil compounds bind to the octopamine receptor and displace the actual neurotransmitter, causing a disruption in the insect’s nervous system. Humans, mammals and birds don’t have these octopamine receptors so it has no effect on them.”
Soft on Beneficials
Bessette says growers using Ecotrol kept telling him beneficial insects returned to the fields within 24 to 48 hours, while fields treated with conventionals had no beneficials at all. Further studies at Washington State University and the University of British Columbia proved that essential oil compounds actually attracted beneficials back into the field. What’s more, the beneficial insects were actually 2.5 to 3 times more tolerant of the essential oils than were feeding pests.
“This shouldn’t actually be shocking when we think that Mother Nature produces these volatiles to attract beneficial insects and get rid of feeding insects, so it makes sense that beneficials would be a little hardier and return to the treated field if they leave,” Bessette says. “So we don’t see the same issues you’re seeing with honeybees and the neonicotinoid class of pesticides.”
But Do They Work?
What really matters ultimately, is whether botanical oils will control pests.
“We are seeing three to four weeks control in the field, equivalent to or better than conventionals,” Bessette says. Ecotrol also works against all stages of the life cycle: eggs, larvae and adults. Bessette says that was something they learned during field trials and helped growers control pests.
“I think it’s also a combination of the attraction of those beneficials back into the field and the fact that even at sub-lethal dosage rates it does still repel the feeding insects. It’s hitting their target receptor sites, so they tend to avoid it.”
“In one recent trial, Ecotrol took out 100 percent of the mite eggs,” he says. “Taking out the eggs certainly brings the population down for an extended period of time. We don’t yet know what’s going on inside the egg, but they either don’t hatch or don’t grow to adulthood, even at sub-lethal doses. There’s something going on that’s causing the insect not to develop properly.”
Consistency and quality control have been concerns with botanicals in the past, because all botanical oils are not created equal. The level of more than a dozen compounds within the oils varies depending on the species, growing conditions and territory.
Bessette says that’s one of the reasons why KeyPlex invested $15 million researching which compounds are actually insecticidal.
“We have specifications we provide to our essential oil partners,” he says. They need to make sure they have certain percentages of marker compounds so we have consistency in our product performance.”
Botanicals are Safe for Plants and People
Extensive testing and usage shows Ecotrol is safe for the plants, too. While there have been natural products in the past that have caused significant phytotoxicity, Bessette says despite even applying it at higher rates than the label recommends, he has not seen any signs of it. “We have been testing and using Ecotrol on acres of plants in the field, not in lab trials in a greenhouse,” he says.
Because botanicals are natural substances, they quickly break down and dissipate in the environment. While this might initially be perceived as a disadvantage by growers used to the longer persistence of products like synthetic pyrethroids, it also allows workers to spray and pick on the same day. Botanicals such as Ecotrol are also exempt from EPA MRLs, giving farmers options to use when a pest crops up after other chemicals have maxed out, or to rotate within their programs to extend the life of other products.
“All of the harder chemistries have some degree of toxicity,” Bessette says. “They are synthetic and not natural, they may have environmental exposure risk where they persist and don’t break down, which is the problem with most of these chemistries in agriculture, and then there’s the acute toxicity issue. You don’t have these issues with natural compounds.”