Thrips Species Composition in Ontario Greenhouse Floriculture: Innovative Identification Tools and Implications for Integrated Pest Management

Simple Summary Thrips are minute insects that, despite their small size, are one of the most damaging and challenging pests affecting ornamental crops. Ontario growers have observed a recent increase in thrips damage that was not adequately controlled by standard biological control programs developed for the primary pest species, Western flower thrips (Frankliniella occidentalis (Pergande)). This led to an assumption that biological control programs were no longer effective or suffered from quality control issues. Proper species identification is critical for successful pest management; however, efforts to identify thrips species in Canadian greenhouses have not been formally made since the 1980s. We sampled thrips communities from eight commercial floriculture greenhouses in the Niagara region (Ontario, Canada) from 2016 to 2019. A secondary species, onion thrips (Thrips tabaci Lindeman), constituted a large percentage of the species found in ornamental crops and appears to be largely responsible for increased crop damage. The recent interception of other exotic thrips species found in ornamental crops further heightens the need for prompt identification when unusual damage or outbreaks occur. As traditional taxonomic keys are inaccessible to non-specialists due to their technical difficulty, we developed a simplified identification key for use by growers and IPM consultants.Abstract Proper species identification is the keystone of successful integrated pest management (IPM). However, efforts to identify thrips species in Canadian greenhouses have not been formally made since the 1980s. In response to recent increases in crop damage, we sampled thrips communities from eight commercial floriculture greenhouses in the Niagara region (Ontario, Canada) from May until August 2016. Selected sites were revisited in 2017, 2018, and 2019 to determine changes in species composition over time. Western flower thrips (Frankliniella occidentalis (Pergande)), along with onion thrips (Thrips tabaci Lindeman), constituted the majority of species found. Other pest species (less than 8% of specimens across all sampling years) included poinsettia thrips (Echinothrips americanus Morgan), chrysanthemum thrips (Thrips nigropilosus Uzel), and Frankliniella fusca (Hinds). Further investigations of thrips outbreaks in Ontario from 2016 to 2023 revealed other important species, including Thrips parvispinus (Karny), Hercinothrips femoralis (Reuter), and Scirtothrips dorsalis Hood. The current biocontrol strategies used in Ontario floriculture crops for western flower thrips do not adequately control onion thrips or other thrips pests in ornamental crops, making identification a fundamental step in determining whether biocontrol or chemical control strategies should be implemented. However, traditional taxonomic keys are inaccessible to non-specialists due to their technical difficulty. Using the data gathered in these surveys, we developed a simplified, illustrated identification key for use by growers and IPM consultants.