Onion vs What’s the difference? Identification, monitoring & damage patterns

Ashley Summerfield1, Sarah Jandricic2, Rose Buitenhuis3 & Cynthia Scott-Dupree1 1. University of Guelph, 2. Ontario Ministry of Food Agriculture & Rural Affairs (OMAFRA), 3. Vineland Research & Innovation Centre

Onion thrips () are a well-established pest of outdoor crops, but in recent years they have become a notable Same plant, different damage pest of greenhouse floriculture crops. Typical biocontrol-based IPM programs don’t appear to work as well for onion thrips as they do for the dominant , Western flower thrips ( occidentalis). Without a one-size-fits-all management Although they attack many of the same crops, the strategy, knowing which thrips species is in your crop is the first step to keeping your thrips populations in check. damage patterns they cause are different

Do I know you? Sticking together OT WFT Species identification requires Monitoring cards are an indispensable tool for keeping an eye on pest populations, close inspection of thrips’ heads but do they work equally well for all thrips species? & shoulders under a microscope Western Efficacy of yellow vs blue cards flower thrips Onion thrips proportions on cards vs crop Onion thrips Three red 80% 80% Onion thrips cause little Western flower thrips feed Grey eyespots eyespots damage to flowers, they feed heavily on flowers between the between the 60% 60% mainly on foliage compound compound eyes 40% 40% eyes Percent of chrysanthemum leaves Long coarse Although smaller, Long coarse 20% 20% damaged by 20 thrips after 2 weeks hairs are only hairs on both onion thrips can cause 60% on the the top and 0% as much (or more!) bottom of the 0% damage to your crop bottom of the Spring Summer Autumn 40% “shoulders” Onion thrips Western than the larger “shoulders” flower thrips Crop Yellow cards (pronotum) (pronotum) 20% western flower thrips. Yellow cards were more effective for In spring & autumn proportions on monitoring On chrysanthemum, 0% There are several other thrips species that frequent floriculture crops, both thrips species inside cards accurately reflect onion thrips proportions in onion thrips damage is so even though these are the most common species, you might chrysanthemum greenhouses the crop, but not in the summer, so use plant taps Onion thrips Western spread uniformly encounter others. If something looks off, ask an expert! instead! flower thrips throughout the foliage

This research project is funded by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), through the Ontario Agri-Food October 2020 Innovation Alliance (Tier 1 grant # UofG2018-3171) With additional support from Beneficial Insectary, BioBest North America, BioWorks, Canadian Greenhouse Conference, Flowers Canada Ontario, & Sierra Biological