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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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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Comparing Biocontrol to Pesticides for Bemisia Whitefly Control in Poinsettia

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T’is poinsettia sticking season once again, and the question always comes down to the same thing: do I use chemicals to control Bemisia whitefly and hope it works this year? Or do I switch to biological control?  Here we show some head to head comparisons that can help you decide.

An in-depth discussion of this topic was also captured by MSU’s “Bug Bites” last year, and I’ve included the video below.

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NEW: Free Online IPM Training for Greenhouse Staff

Need a refresher on specific pests of floriculture, and what to do about them? Want to see how Canada – a world leader in biological control in ornamental crops – does things?

Then the following IPM training videos, made by specialists and consultants in Ontario, are for you!

Keep reading to learn how to access these videos, and the topics they cover.

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New Chemical Control Option for Thrips and Whitefly

Thrips-tabaci-female-1-1024x683A new pesticide is available  for greenhouse ornamental production in Canada that has shown potential for effective suppression of difficult-to-control thrips and whitefly species.

But to keep this new tool effective, growers will have to use this chemical wisely. Keep reading for  efficacy data on ornamental crops and best management practices for incorporating this chemical into your IPM toolbox.

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Biocontrol of Bemisia: 7 Things to Consider Before You Turn to Chemicals.

turning color.jpgIt’s that time of year again where it’s “do or die” time in Poinsettia: either your biocontrol program is on track, or it’s time to see if pesticides work.

Here’s what to look for in your crop to help you make the decision, including acceptable infestation levels and evidence of successful biocontrol.

This post also contains information on chemical options for Bemisia whitefly in 2019.

Continue reading “Biocontrol of Bemisia: 7 Things to Consider Before You Turn to Chemicals.”

Poinsettias: To Spray or Not to Spray, that is the Question

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T’is poinsettia sticking season once again, and the question always comes down to the same thing: do I use chemicals to control Bemisia whitefly and hope it works this year? Or do I switch to biological control?  Here we show some head to head comparisons that can help you decide.

Continue reading “Poinsettias: To Spray or Not to Spray, that is the Question”

2018 Poinsettia Wrap Up: Whitefly and Pesticides

Bemisia 4_SJAs suspected, it’s turned out to be a heck of year for Poinsettia.  Many growers faced Erwinia, others had rooting issues, and all faced significant pressure from Bemisia whitefly from infested cuttings.

As the time approaches for the plants to go out the door, this post covers whitefly control successes/failures in 2018, and what to do with remaining populations.

Whitefly and other poinsettia issues are also being discussed at the Niagara Poinsettia Open House on Tuesday, November 20th. This will take place at Jefferys Greenhouse (Plant II) starting at 10 am.  See the latest issue of Greenhouse Canada Magazine for more information (pg. 28). Hope to see many of you there.

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Worried About Whitefly? Control Strategies in Poinsettia for 2018.

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Bemisia whitefly (Bemisia tabaca) adults on poinsettia.  In high pressure years, poinsettia plants can quickly become unsellable due to this pest.

The floriculture industry in Ontario seems to have mostly avoided heavy aphid AND thrips pressure this spring/summer.  But from everything I’ve been hearing, we are NOT going to be that lucky with whitefly on poinsettia this year.

 

This  post goes over preventative measures that should be taken as soon as cuttings come in the door, biocontrol programs for whitefly on poinsettia, and WHEN and WHAT to spray for this so you can avoid resistance issues.

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Lassoing Loopers: why you NEED to care about caterpillar control

tomato looper 2_Steve hatch
Know which looper species this is? Are you SURE? If not, keep reading, as some species could get your shipments detained at the border.  Photo: Steve Hatch, Bugwood.org.

With spring crops behind us and summer approaching, most of you are probably concentrating on the Big 3: thrips, aphids and whitefly.  But recent alerts put out by the United States Department of Agriculture (USDA), bring a new emphasis to caterpillar control.  Read on to understand what’s happening, how to control occasional pests like cabbage looper, and avoid potential issues at the border.

 

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