Dip, cool or steam? Clean Start treatments for Thrips parvispinus

Mandevilla cuttings in propagation with different treatment tags in them.

This post written by Ashley Summerfield (M.Sc.), Senior Research Technician in the Biocontrol Lab at the Vineland Research and Innovation Centre.

They say that “an ounce of prevention is worth a pound of the cure” and nowhere is this truer than in IPM. Reducing the incoming number of invading pests will inevitably improve the success of any pest management strategy.

This post covers recent research advances made by Vineland Research on treatments of propagative plant material to help control Thrips parvisipinus. This includes effects of treatments on all thrips life stages, including eggs, as well as potential phytotoxicity of treatments on tropical plants.

This post also includes a link to the recent webinar on starting clean for Parvi recorded by Flowers Canada Growers, if you prefer that format!

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In Case You Missed It: Two-Spot Cotton Leafhopper – a New Pest of Hibiscus.

*Fig. 1.* *Two-spot cotton leafhopper. Photo by A. Revynthi, University of Florida.*

Just when we think we have Thrips parvispinus under control, a new pest is threatening tropical ornamentals. The two-spot cotton leafhopper (Amrasca biguttula) is mainly a pest of – you guessed it, COTTON – but also attacks hibiscus. Growers in Ontario should be aware of this pest if importing hibiscus cuttings from the Southern U.S., where this pest has currently invaded.

There’s been lots of good information shared on this pest recently. Read on for a summary relevant to ornamental growers, including what to look for, effective pesticides and what actions you should take NOW.

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GrowON Webinar, September 24th: Thrips parvispinus Control – Where We’re At and Where We’re Headed.

To make sure growers have the latest information on new thrips pests affecting greenhouse crops, GrowON is running a 3 part webinar series on thrips besides western flower thrips. The second installment will be on Thrips parvispinus (also known as pepper thrips) on Wednesday, September 24th with Sarah Jandricic (OMAFA).

To attend, please use the registration link in the post below.

Parvi poster Sept 2025_final Download

Description:

When it comes to Thrips parvispinus control, many growers are asking, are we there yet? Join us to learn where we are in terms of biocontrol and chemical control for this invasive pest. This presentation will summarize research being conducted in Ontario, Florida and Europe, and put it into context in terms of strategies growers can implement now. Future research directions will also be discussed.

Note, this presentation was given live at Greenhouse Canada’s Grower Day in June 2025. This webinar is hoping to reach those that weren’t able to attend in person!

Time: Wednesday, September 24th, 12-1pm

Registration:

Please register for Part 2 of this Webinar series by using this link: https://us06web.zoom.us/webinar/register/WN_30N3jt1KRbOyva0s7oh5Dg

NEW DATE: GrowON Webinar on Japanese Flower Thrips now Wednesday August 27th

To make sure growers have the latest information on new thrips pests affecting greenhouse crops, GrowON is running a 3 part webinar series on thrips besides western flower thrips. The first installment will be on Japanese flower thrips on August 27th, with Judy Colley (Plant Products) and Sarah Jandricic (OMAFA).

To attend, please use the registration link in the post below. If you’ve already registered, you’re still good for the new date of the 27th!

Setosus webinar poster July 2025 Download

Description:

Another new thrips on the block? Thrips setosus, also known as the Japanese flower thrips, affects hydrangeas, cyclamen, herbs and more. Judy Colley, technical lead for Plant Products, will share information on greenhouse trials for controlling this pest. She will be joined by Dr. Sarah Jandricic (OMAFA) who will cover biology, hosts plants, damage and current research. She will also go over pesticide options.

Time: Wednesday, August 27th, 12-1pm

Registration:

Please register for Part 1 of this Webinar series by using this link: https://us06web.zoom.us/webinar/register/WN_30N3jt1KRbOyva0s7oh5Dg

GrowON’s “More than Just Westerns” Thrips Webinar Series, Part 1: Japanese Flower Thrips

Over the past few years, we seem to be battling a whole new posse of thrips species. First it was onion thrips moseying on up into our chrysanthemums and gerbera. Then, it was Parvispinus, which was like a runaway train in our tropicals. Now, it’s Japanese flower thrips (Thrips setosus), riding into town on crops like hydrangea.

To make sure growers have the latest information on these pests, GrowON is running a 3 part webinar series on thrips besides western flower thrips. The first installment will be on Japanese flower thrips on August 20th. Read on for how to register for this free webinar.

*A lineup of thrips species that attack greenhouse ornamentals. Can you pick out the usual suspects from the new kids in town? Photo by A. Summerfield, Vineland.*

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“COMMUNITY” PEST ALERT: Spotted Lanternfly

Originally published on the ONgreenhousevegetables blog on October 15, 2024 by Cara McCreary

*A spotted lanternfly adult. Photo by APHIS.*

They may be pretty, but they aren’t our friends. Spotted lanternfly (SLF) is an invasive sap-feeding planthopper with potential to harm agriculture and forestry in Ontario.

But I only grow greenhouse fruits and vegetables, so why does it matter to me, you ask? Read on to learn more about why this pest matters to everyone.

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“How-to” Video of the Week: Plant Washes and Other Tools to Make Detecting Parvispinus Easier

*OMAFA Summer Student Avery Johnson demonstrating plant washes on-farm.*

In this week’s “how-to” video, we’ll explore using plant washes on-farm.

Plant washes are a simple but effective method to detect low levels of critical pests, such as Thrips parvispinus.

Once you’ve washed out your pests, we’ve also developed a quick “decision tree” to help you easily determine if you’re dealing with Thrips parvispinus or another thrips pest.

Keep reading to find the link to the video and additional resources.

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Potted Chrysanthemums 2024: Dips, Thrips and Threats

Every year at this time, growers start to think about strategies to minimizing western flower thrips on their chrysanthemum crops. This year, Thrips parvispinus is causing extra concern, given that chrysanthemum is one of its reported hosts.

Although there have been no reports yet of Parvispinus damaging chrysanthemums in North America, it’s still good to exercise a bit of caution. However, jumping the gun and spraying chemicals will likely just disrupt your biocontrol program for western flower thrips, leaving you with a bigger mess on your hands.

This post contains information on things you can do to put your mind at ease about all sorts of thrips this chrysanthemum season.

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Parvispinus on Poinsettias? It’s Possible.

Fig. 1. *Parvispinus feeding on a poinsettia leaf.*

Growers in Ontario continue to struggle with Thrips parvispinus on tropical crops like mandevilla, anthurium and schefflera. Unfortunately, reports out of Europe also indicate this invasive pest species can also attack poinsettia.

Read on for what you need to watch out for, and potential management strategies.

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Got Tropicals? How to Detect and Monitor for Thrips parvispinus.

*Figure 1.* Thrips parvispinus female. Photo by A. Summerfield, Vineland.

In a previous blog post, we talked about which pesticides can control Thrips parvispinus if you end up with an infestation from imported plant material.

But how do you figure out if this invasive pest is in your facility in the first place? And, if so, what’s the best way to monitor their populations?

After working with this pest for the last 1-2 years, researchers like myself have figured out which monitoring methods are most effective. This can help you identify the problem early, begin a management plan, and monitor the efficacy of your controls.

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