From Pheromones to Predators: What “Bugs in the North” Teaches Us About Insect Management

From wheat midge to lady beetle, insects can help or harm crops. As weather patterns and insect populations shift with climate change, farmers face a moving target, making research on insect management more important than ever. 

Published in the Canadian Journal of Plant Science, “Bugs in the North: Insect‑Crop Interactions in Continental Climate Agriculture” is a collection guest‑edited by Dr. Tyler Wist, Dr. Hector Cárcamo, Dr. Boyd Mori, and Dr. Annie‑Ève Gagnon that brings together recent research in insect–crop interactions. In this interview, Lead Guest Editor Dr. Wist, a field crop entomologist with Agriculture and Agri-Food Canada in Saskatoon, reflects on what these studies reveal and where the field is headed. 

What sparked your interest in field crop entomology, and are there particular insect species that you are currently focusing on? 

My interest came about with a project where I was looking at what species of cereal aphids were present in wheat fields and which beneficial insects were present and may be feeding on them. I realized that agriculture was a great place to be doing entomology, and I stuck around!  

Bugs in the North’s papers include a range of study sites and a variety of crops and insect species. What management strategies do we see arising in this research?  

One common thread was between three papers that dealt with management strategies using pheromone attractants and, in one case, floral attractants (van Herk et al. 2024, van Herk et al. 2025a, van Herk et al. 2025b). Pheromones are chemicals signals used by various species to attract adults who are looking to mate, and so you can use pheromones in a mass trapping strategy—meaning that you catch so many that you can depopulate the mating population.  

But first, you have to test how those pheromones work. In these studies, they seem to be doing a good job of capturing the insects that they were supposed to.  

How are the pheromones manufactured and tested?  

First, you need an entomologist to figure out the problem. For instance, can those insects be attracted by a pheromone lure? Wim Van Herk has been working on click beetles for a few years, and they realised that not all the beetles were using pheromone attraction for mating. One of the species was actually all female, so there were no males to react to a pheromone;therefore a pheromone won’t work for that species.   

You identify the system, and then, if it’s a female-produced sex pheromone, you need to catch enough females to either extract the pheromone from the pheromone gland or encourage them to start pheromone calling and then trap the chemicals that are coming off. The entomologist then gives way to the chemical ecologists who determine what the pheromone components are and whether they elicit an antennal reaction. The chemical ecologist tries to synthesize those compounds, and at this point, the entomologist or the behavioural ecologist gather a bunch of males and introduce those chemicals to see if the males are attracted to them. If you find a blend or compound that works in the lab, then you can take it out in the field.  

In Bugs in the North, we mainly see papers in the last stage—testing it out in the field.  

What findings from the collection would you recommend sharing with producers (i.e., farmers and agronomists)? 

If you are a producer and you want to manage insects, your questions would be: what are these insects and what could be in my crop? 

All papers in the collection deal with economically important insect species, but in different crop production systems. Some deal with tracking the population spread of various pest insects. One addresses gaps in economic impact estimates in field crop production (Srivastava et al. 2025), while others provide baseline descriptions of pests and new crops in northern regions (Chennamkulangara et al. 2025, LaForest and Mori 2025, Lefebvre et al. 2025, Wijerathna et al. 2025). The collection covers everything from blueberries to corn production to pulses and alfalfa (Aguiar-Cordero and Prager 2025, Gervais et al. 2025, Shi et al. 2025). 

Bracon cephi (wheat stem sawfly parasitoid). Credit: Tyler Wist

Some of the key information from these papers would give farmers a new pheromone tool to attract those click beetles (the adult stage of wire worms) (van Herk et al. 2025b). Researchers were also looking to determine the level of resistance to insecticides by Colorado potato beetle, which is the worst pest in potatoes (Ménard et al. 2025). For farmers, if you lose a chemical tool for controlling a pest, then you need to know that before you go out and spray. 

Evaluating kaolin clay as a pest management tool against flea beetles was interesting, as that could potentially be used in more of an organic market. I don’t think kaolin clay falls under your typical insecticide category (Rajan and Cutler 2025). 

In their paper, Beres’s team (2025) suggests a method to enhance the biocontrol of wheat stem sawfly by leaving wheat straw as tall as possible if you’re in a wheat stem sawfly area, because that preserves the overwintering habitat of the Braconid wasp, Bracon cephi, a species that helps to suppress wheat stem sawfly populations and which pupates up in the wheat stem. That’s one practical way to help your local biocontrol agents.  

What roles are beneficial insects playing in pest management recommendations? 

You can consider these biocontrol agents or beneficial insects in an integrated pest management setting, but you need to know what they’re doing. How many pest insects can they kill in a day? What sort of conditions do they need to survive?  

We mentioned the Braconid wasp; another example is honeybees, which are a totally different kind of beneficial insect— you’re counting on them to pollinate your crops. That paper (Limay-Rios et al. 2025) was looking at the effects of potential insecticide exposure on the flowers around the field. 

You may not think that a cricket could be a beneficial insect, but they actually eat grasshopper eggs. In MacKeil’s paper (2025), researchers were looking at weed seed predation. How many weed seeds were these crickets eating in a blueberry system?  

Beneficial insects can help regulate insect pest populations, either through predation or parasitism. But it’s difficult to understand that whole system. The relative contribution to biocontrol of a single insect species can be estimated based on something called voracity, which is the number of insects they can kill in a day. But it gets complicated when you’ve got several different insect pests and many different beneficial insects in a field.  

More recently, our team has developed a dynamic action threshold to look at the dynamics between pest insects and beneficial insects, from which we developed an app called the Cereal Aphid Manager, which is freely available online.The app measures things like how many aphids are taken out of the equation by this beneficial insect, and what the populations may look like in a few days in the field you’re looking at. 

How is climate change affecting how scientists approach research in this field? 

We know that the environment affects insects hugely. Scientists will generally take what we know about the thermal effect on insects—is it too hot for them? Is it too cold for them?—to find the optimum temperature for them to reproduce and then model how those populations might expand or contract under different future climate scenarios. 

Two of the collection papers include bioclimatic modelling of insect populations. For example, how the cabbage seed pod weevil might react if agricultural farmland experienced increased warming (Weiss et al. 2025). Another studied the environmental effects on the prevalence of lygus bug populations in fava beans (Aguiar-Cordero and Prager 2025).  

Another paper looked at what information scientists need to collect from pest insects to be able to model what they might do in the future. That could then allow scientists to make predictions about future damage under different climate scenarios. 

Where do you see this area of research heading?  

The paper on economic threshold gaps (Srivastava et al. 2025) addresses what sort of research will be needed in the future. What were the biggest pest insect species, how big of an impact did they have on the acreage in Western Canada, and can we put a dollar sign to that? 

And finally, what’s your favourite interesting or surprising insect fact you’ve come across in your work?

Aphid lion killing aphid. Credit: Tyler Wist

One of the beneficial insects that eats aphids is called a green lacewing larva. Its common name is the aphid lion. It gets that name because it grabs an aphid and it shakes it over its head, like a lion trying to break the back of a lamb or something.

Definitely a top predator. And they have these huge hollow mandibles that are longer than their head, and they use them to catch aphids and inject them with a digestive enzyme. They then suck out the digested aphid guts,leaving behind only the shell of the aphid.

 Around here, we see two species. I’ve even been bitten by one. I was holding it for a class, showing off, “Hey, this is an aphid lion, check it out,” and then it bit me, and I thought, well, this could be interesting. Pretty quickly I could feel those digestive enzymes, and I thought, all right, well, let’s stop this, because I don’t need a big red bump on my hand.