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.

Continue reading →

In Case you Missed it: UofF Webinar on Latest Thrips parvispinus Research

On March 12th, 2025, Dr. Alexandra Revynthi’s lab (University of Florida) gave an amazing update on what they’ve been working on with regards to Thrips parvispinus. A lot of this was important basic knowledge about their biology, such as development time and survival at high temperatures. There were also quite a few lab and small greenhouse trials looking at potential biocontrol agents.

Some of this will be information we build on to create effective IPM programs for Parvi in the future. But some of these findings, you could put into use right now.

You can go watch the full webinar using the link in the full blog post, or read my summary notes and see what I thought were the important take-aways.

Continue reading →

High Quality Photos for Thrips Identification: Rating Phone Attachments.

This is a guest post by Avery Johnson (former OMAFA summer student and current M.Sc. student studying Thrips parvispinus) and S. Jandricic.

Having difficulty identifying thrips on sticky cards and need clear photos to send to your consultant or extension agent? Don’t want to invest in a microscope? Well, you’re in luck, because we’ve done the legwork to find some good alternatives to get high quality photos.

Continue reading →

Pesticide Rotation Guide for Thrips parvispinus in Canadian Greenhouses

By Sarah Jandricic (OMAFA) and Judy Colley (Plant Products)

*A female (left) and male (right) Thrips parvispinus on a mandevilla flower.*

With the arrival of mandevilla, dipladenia and hibiscus cuttings, now is the time to start planning your management program for Thrips parvispinus. Unfortunately, it looks like this pest is here to stay in North America, and in the tropical plant industry at large.

In this post, we’ll focus on pesticide rotations to manage pesticide resistance, as well as a few tips and tricks to make sure your pesticides stay working.

Continue reading →

“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.

Continue reading →

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.

Continue reading →

In Case you Missed it: “A Pain in the Parvi” GrowON Webinar Recording (Plus, Another Thrips parvipsinus Webinar with GrowPro!)

In case you missed the GrowON webinar by myself and Judy Colley from Plant Products on Jan 29th, we’ve now uploaded to Youtube!

You can find it the ONFloriculture Youtube page, along with lots of other useful videos and webinars.

Are recorded webinars not your thing? Well, then you have two additional options!

Continue reading →

Trap Plants as a Tool Against Thrips parvispinus in Tropicals

*Sweet alyssum (Lobularia) as a trap plant for T. parvispinus.*

Thrips parvispinus has become a serious pest of tropical ornamental crops in North American since 2020. Due to the severity of the damage, IPM strategies are needed to complement chemical control until an effective and economical biocontrol program can be developed for this pest.

Mass trapping through traps, lures, or trap plants can be an effective strategy for thrips. We’ve already seen that mass trapping cards REALLY help with this pest (more on that, later). And, it seems that trap plants may also be an effective strategy when used properly in vegetative crops.

Read on for what we did and how to implement it on YOUR farm.

Continue reading →

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.

Continue reading →

Thrips parvispinus (“Pepper Thrips”): The Importance of Inspecting Plants and Dipping Cuttings from Florida

I’ve written about the tropical pest Thrips parvispinus, now being called “pepper thrips”, infesting certain tropical ornamentals in Canada before. But it appears this pest has become widespread in Florida.

As Ontario sources much of its plant material from Florida, it’s a good idea to exercise caution, even on non-tropical plants. The known host range of this pest is evolving, and thrips have the potential to hitch-hike on less-preferred plant hosts and spread to more preferred hosts in your greenhouse.

Read on for information on the situation in Florida and what you can do to help protect your greenhouse from this pest.

Continue reading →