Controlling Parvispinus, Oleander Aphid and Spider Mites in Mandevilla: Part 2 – Spider Mite Resistance Management.

Last week, I posted an updated IPM plan for Mandevilla that balances Thrips parvispinus (“Parvi”) control while taking into consideration other pests, as well as costs. The last post covered propagation in detail, including biocontrols and chemicals.

This week I’ll be going over the best way to balance control of Thrips parvispinus (“Parvi”) and two-spotted spider mite (TSSM) in production. I’ll provide a working Parvi spray program that gives you high-quality plants by sale, but also makes sure spider mites don’t walk away with your crop (or your wallet!).

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Managing Pesticide Resistance in Greenhouse Crops

With July being the beginning of poinsettia season, as well as the time growers are starting many tropical plants for next spring, it’s time to be thinking about managing pesticide resistance. Pesticide resistance readily develops in populations of key greenhouse pests, including Bemisia whitefly, spider mites, and more. So how do we avoid an uphill run on the resistance treadmill?

Hannah Fraser, Horticulture Entomologist with OMAFA, shared her decades of experience battling resistance issues in fruit crop pests in a GrowON webinar recorded last summer. For those that missed it, I thought now would be a good time to post the video on the blog. (As always, you can find all of our previous GrowON webinars on the ONFloriculture Youtube channel.) Keep reading to watch the video as well as links to other resources on resistance management.

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Is Beleaf Still Working for Aphid Control? What We Know So Far and Alternative Chemicals for Spring 2025.

For those of you relying on chemical control for aphids in spring crops, some of you might have observed that Beleaf (Aria in the U.S.) has not been working as well recently, especially in green peach aphid (Myzus persicae).

This post will fill you in on what we know about potential resistance to flonicamid in aphids, and which chemicals are working.

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Upcoming GrowON Webinar: Managing Pesticide Resistance in Greenhouses

Greenhouse IPM practitioners have to produce high quality plants and produce with a more limited chemical arsenal. We also have to deal with several key pests that are known to readily develop resistance to multiple chemical classes, including thrips, whitefly and leafminers. So how do we avoid an uphill run on the resistance treadmill?

Hannah Fraser, Horticulture Entomologist with OMAFA, shares her decades of experience battling resistance issues in fruit crop pests with us in this next webinar.

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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.

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Pesticides for Parvispinus: Results of an On-Farm Trial

*Female T. parvispinus (left) on a mandevilla flower; a smaller male (yellow, right) can also be seen.*

Although the invasive pest Thrips parvispinus continues to threaten tropical ornamental crops, the good news is that the sky isn’t falling. Producing crops like mandevilla, schefflera and hoya is still possible, at least in a closed greenhouse setting.

Although developing a reliable biological control program for this pest is probably a few years off, a suite of pesticides is available in the U.S. and Canada to successfully manage T. parvispinus.

This post covers these pesticides, their relative efficacy and demonstrates outcomes when used in an 8 month on-farm trial in mandevilla.

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