Pesticide resistance levels in field and greenhouse populations of Tetranychus urticae

Citation

Moreira do Nascimento, J. V. Zhurov, H. Varonina, J. Spenler, Z. Ćulo, A. Rahn, E. Surman, J. Gallo, I. Scott, D. Lizotte, T. Baute, T. MacDonald, N. Bennett, M. Grbić and V. Grbić. 2022. Pesticide resistance levels in field and greenhouse populations of Tetranychus urticae. Poster presentation at the Ontario Pest Management Conference, Guelph, November 1, 2022.

Résumé en langage clair

Dimethoate, an organophosphate insecticide, is the only registered pesticide to manage two-spotted spider mites (TSSM) for soybeans in Ontario. The objective of the project was to assess pesticide resistance in TSSM populations in fields and greenhouses from Southwestern Ontario in 2021. Seventy percent of mite populations collected from soybean and all greenhouse populations were resistant to dimethoate. Other results indicate that resistance to multiple pesticides was present in the majority of the sampled populations, with the greenhouse-collected populations being the most resistant. The assessment may inform a choice of additional pesticide registration for spider mite control on soybean, considering that dimethoate has limited effectiveness.

Résumé

Two-spotted spider mite, Tetranychus urticae (Koch), is a chelicerate herbivore with an exceptionally wide host range. It is a frequent pest of a wide variety of economically important crops. While low-level infestations are controlled by biological agents such as beneficial predatory mites, midges, and bugs, chemical controls are frequently implemented for persistent pest populations. However, pesticide resistance is frequently reported in T. urticae populations across the globe. Here we present a 2021 assessment of pesticide resistance of T. urticae populations coming from Southwestern Ontario. Our study covered a variety of crops (cucumber, pepper, strawberry, tomato, and soybean), and production systems (greenhouse and field). The assessed active compounds were abamectin, bifenazate, cyflumetofen, dimethoate, etoxazole, pyridaben, and spiromesifen. Our results indicate that resistance to multiple pesticides was present in the majority of the sampled populations with the greenhouse-collected populations being the most resistant. These results may be used to prioritize and plan pesticide usage on crops where multiple products are registered. Our assessment may also inform a choice of additional pesticide registration for spider mite control on soybean, which is currently performed exclusively with dimethoate that was demonstrated to have limited effectiveness.

Date de publication

2022-11-01

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