Botanical Insecticides Offer More Flexibility Than You Might Think

Dr. Murray IsmanBotanical insecticides based on plant essential oils or plant extracts have been around forever. But growers are using them in modern ways that offer more flexibility and control over a pest management program.

Dr. Murray B. Isman, Professor (Entomology/Toxicology) at the University of British Columbia, has been focusing research on botanical insecticides and shared some of the developments he’s seeing at the recent Biocontrols USA West 2017 Conference & Expo.

We spoke with Dr. Isman about some of the advances with these products and how you can apply them in your own production next season.

Q: Why do you think you’re seeing more adoption of some of the botanical insecticides among growers now?

Isman: More growers appear to be adopting botanical insecticides in part because the arsenal of conventional crop protectants is being progressively whittled down by regulatory actions. While there are new conventional products being brought to market, their numbers are well down from a couple of decades ago, and far fewer in comparison to the number of products withdrawn from the marketplace. Another factor is that the younger generation of growers are better educated — therefore more willing to try alternative products and technologies — and more concerned with long-term sustainability of their livelihoods and the environment.

Q: What are some of the direct benefits botanical products provide in comparison to other types of materials?

Isman: Botanicals are certainly not a panacea for crop protection, but they do offer minimal, if any, harvest restrictions, fewer other restrictions on use, and generally good compatibility with biocontrols. They are also compatible with other pest management products and can be used as tank mixes or in rotation, so they offer a lot of flexibility.

Q: How are some of the newer botanical insecticides different from past materials, and how are growers using them?

Isman: The products based on essential oils provide rapid contact action, but with the advantage of residual action that is not based on toxicity but on behavioral effects on pests. In short, they can provide protection for days or weeks after their immediate effect has diminished because they continue to repel or deter pests from recolonizing crops plants and/or laying eggs. In some pest/crop combinations we have seen good residual action, but without the problematic pesticide residues associated with conventional insecticides.

Q: What was one of the more unexpected topics for attendees you covered during the session?

Isman: Unlike most conventional pesticides that smell awful, most of the essential oil-based products actually smell quite pleasant! On a more serious note, most botanicals are based on natural mixtures rather than a single bioactive chemical. As such, the probability of insect populations developing resistance is tiny relative to the probability with a conventional insecticide or even a microbial like Bt.

To get more information about the recent Biocontrols USA West event or the Biocontrols Conference & Expo Series for 2017, visit