A Smarter, Balanced Approach to Advanced Pest Management
In modern agriculture, success is a delicate balance. Farmers are constantly navigating a complex set of priorities: achieving high yields, ensuring crop quality, protecting the environment, and securing their livelihoods.
Today, farmers need bold and holistic solutions to battle the challenges that they’re facing. Global crop production losses to pests are significantly high at 20% to 40%, costing the global economy billions annually.
Pest management means more than effective control of pests. Modern solutions must also meet the highest standards for environmental health and safety, support yield optimization, and safeguard access to global markets.
For decades, growers have had to make trade-offs between these priorities too often. Now, Bayer has developed the next-generation ketoenol insecticide, that’s designed to balance all these priorities, offering a smart solution that delivers on all fronts.
Plenexos® is the culmination of over thirty years of expertise in ketoenol chemistry that our scientists set out with a bold vision: to develop an insecticide that is not just powerful, but also versatile, efficient, and sustainable.
To better understand the unique features of Plenexos®, its two-way systemic action, and how it delivers all-around protection, even to new growth, we literally went back to the roots.
In the below Q&A, long-time Bayer scientist and "father of ketoenols" Reiner Fischer discusses the journey of a revolutionary class of insecticides he and colleagues discovered nearly 40 years ago, and how Plenexos® is set to become Bayer's next agricultural blockbuster as teams in Brazil prepare for its 2026 launch.
Reiner, thanks for taking some time with us today. To start, can you tell us a bit about yourself, your background with ketoenols, and your role at Bayer?
Okay, my name is Reiner Fischer. I started my career at Bayer in 1985 in central research, working on herbicides. I guess I've also been called the father of ketoenol acaricides (which control ticks and mites) and insecticides and officially retired in November 2019. Since May 2021, I am back on a special assignment as we develop and prepare to launch Plenexos®.
In 1987 we worked on PPO inhibitors, so a class of herbicides that works by disrupting chlorophyll production in susceptible plants. In changing the structure of these molecules, we found a spectrum shift from efficacy in dicot weeds, typically referred to as broadleaf weeds, to monocot weeds (or grassy weeds) which was the trigger for further investigations. With continued work we observed an indication shift to spider mites. This mode of action was not known at that time, so we had something in our hands that was really new. Such an event happens maybe every 10 or 20 years, and this was our inspiration to follow up this substance class of ketoenols.
What do you see as farmers' biggest challenges when it comes to insect pests?
One of the challenges is resistance of insects and mites to other commercial products. Pests like whiteflies and spider mites can destroy the whole crop. A farmer cannot harvest anything! The impact can be very dramatic with some of these pests.
Other challenges are regulatory requirements scrutinizing residue levels of pesticides in fruits and vegetables, and this is very important in the food value chain. Looking back to the beginning of the 90s.
The arrival of ketoenols a few decades ago brought a step change improvement over commercial products on the market at that time. Plenexos® is also a ketoenol, so how is it different?
Plenexos® is what we call a free ketoenol meaning it is a drug itself and is "ready for work" upon entering the plant. Compared to our other products like and Movento®, which are still very effective prodrugs, Plenexos® has completely different properties. The leaf uptake of Plenexos® is very high. Once inside the plant, the active ingredient is moving up and down in the plant, even reaching hidden pests. These properties allow Plenexos® to efficiently control sucking pests like aphids, whiteflies, scales, psyllids, and mealybugs in different crops soybean, cotton, and fruits and vegetables with long-lasting efficacy and very low application rates. very important to ensure low residues in the commodities.
Due to its mobility in the plant, even new shoots are protected. That is what farmers want to have, because in the past they had to spray every three to five days. There can be more than 20 sprays per season to manage cotton crops in Brazil, for example.
How does Plenexos® address concerns of keeping safe beneficial insects?
To be affected by Plenexos®, the pest has to ingest the compound. The beneficial insects are not coming in contact with the compound because they are not feeding from the plant. It's very selective to control sucking pests, with little or no exposure to non-target insects.
Anything you'd like to add?
I believe it's important to add that the compound has a very favorable toxicological and ecotoxicological profile. I have never seen such a minor toxic compound in insecticides. Plenexos® offers a combined, balanced package for the farmer. They'll have more convenience, flexibility, and safety in managing their crops. They'll need less fuel and water, less manpower and fewer applications throughout the season. We are offering them a kind of insurance, a remarkable product.