Rethinking insect pests in the garden

European hornet. Image: Krzysztof Niewolny on Pixabay

This past May, my normal calm demeanor was temporarily disrupted when the hornet above flew around me on my back deck. At the outset of my gardening life, I probably would have been so alarmed that I would have tried to kill it. Not so today. While wasps have been historically vilified as dangerous garden pests, the advocacy for integrated pest management (IPM)* in home and rural gardens has made us very aware of the benefits of many solitary and eusocial wasps in our landscapes.

Rethinking pests, I first photographed it and uploaded the shot to INaturalist where I discovered it was indeed a non-native European hornet – Vespa crabro. This is the largest social wasp native to Europe, and the only true hornet found in Ontario. Easy research thanks to the internet gave me enough information to allow me to relax. I read about its life cycle, its nesting habits, and its feeding behavior. I compared it to the Japanese giant hornet which does pose real danger to honeybee colonies, but which has not yet been seen beyond British Columbia. 

Veronicastrum virginicum with sphecid wasp feeding. Image: Nancy Shepherd

This incident made me acutely aware of how our behavior towards wasps has really changed, as many gardeners now choose garden perennials and annuals to bring beneficials in to their yards to help deal with real pests. I enjoy the braconid wasps, the ichneumon wasps, and the sphecid wasps as much as I do the chubby bumble bees flying though my gardens. And when my vigilant monitoring of plants and pests reveals damage, I never turn to chemical intervention. The answer usually is with cultural, mechanical, and biological controls- all so much better for our local ecosystems and their wildlife.

The following resources are extremely helpful for rethinking pests. ‘Natural Enemies in your Garden’ can be downloaded from the University of Michigan website

For information on local pests and identification guides, check out The Big Bug Hunt

And for more interesting information about wasps, check out these three new books: 

*Integrated pest management relies on proper identification of a garden problem or pest and uses multiple control measures working together to manage pests. This could include a combination of mechanical methods (handpicking insects, floating row covers), cultural practices (appropriate plant selection including disease resistant cultivars, correct watering), biological controls and as a last resort the sensible use of chemicals.