Nesi bugs – ONGreenhouseVegetables

Creature Feature: Nesi — The Green Bug That’s Not Always Good News

Published on July 6, 2026August 12, 2026 by Julia Dubeau

Authors: Julia Dubeau (Research Assistant, OMAFA), Rose Labbé, PhD (Research Scientist, Greenhouse Entomology, AAFC), and Cara McCreary (Greenhouse Vegetable IPM Specialist, OMAFA)

Meet the Creature

For this Creature Feature, we’re meeting Nesidiocoris tenuis, commonly known as Nesi, green bug, or tomato bug.

Close-up of a green late-instar Nesi nymph with developing wing buds

Nesi is a small green mirid bug that has become a concern for Ontario greenhouse vegetable growers – specifically greenhouse tomatoes and greenhouse cucumbers but greenhouse peppers are also a potential host.

At first glance, Nesi might not look too scary. It is small, green, and easy to mistake for something helpful. But this is one of those “don’t judge a bug by its colour” situations — not every green bug in the crop is a good bug!

Nesi is an omnivorous mirid, meaning it can feed on both insects and plant tissue. In some regions around the world, it has been used as a beneficial insect, but in Ontario greenhouse vegetable production it is considered a pest because of the plant damage it can cause.

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PYGANIC® Insecticide label temporarily expanded via Emergency Use Registration request to help manage Nesidiocoris tenuis in greenhouse grown tomatoes and greenhouse grown cucumbers in Ontario.

Published on April 17, 2026April 17, 2026 by Cara McCreary1 Comment

J. MOSIONDZ, OMAFA, Minor Use Coordinator, Guelph

The Pesticides Regulatory Directorate (PRD), formerly known as the Pest Management Regulatory Agency (PMRA), recently announced the approval of an Emergency Use Registration (EUR) request for PYGANIC^®insecticide for management of Nesidiocoris tenuis, “Nesi”, on greenhouse grown cucumbers and greenhouse grown tomatoes in Ontario. This EUR request can be used only in Ontario from April 17^th, 2026, until April 16^th, 2029. The request marks the first agricultural related EUR request to be granted a multiyear term on the grounds of preventing the establishment of a new invasive species.

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Mirid Identification Resources

Published on January 14, 2026 by Cara McCreary1 Comment

Below you will find details to assist with identifying some key mirid species. The focus is distinguishing between Dicyphus hesperus, a beneficial mirid, and Nesidiocoris tenuis, a pest mirid. This material was presented in the Tools of the Trade Workshop at the 2025 Canadian Greenhouse Conference.

These PDF’s can be downloaded and used as reference material. They can be printed on letter size paper.

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