How to control thrip long-term?

Morning gardeners,

We have 5 big viburnum bushes (non-flowering) in our apartment courtyard, and they're infested with thrips.

Last year we trimmed it right back, removing every leaf, and disposed of the waste quick smart. The bushes grew back quickly, and were really healthy, but the thrips have infested them again. I've heard that they lay eggs in either the soil, or the branches (or both?).

We're going to trim them back again mid-winter, ready for the spring growth, but it anyone has advice as to how to deal with the thrips before they hatch that would be helpful. Do we treat the soil? (there's a layer of mulch) Spray the branches?

Whatever we do has to happen in winter, as there's a silvereye nest in there, so we can't use chemicals in spring (they migrate North in late summer and come back in spring).

Thanks in advance.

Find more posts tagged with

Gardening

Planting and Growing

Comments

KatieC

Hi @DIY_Dinkum,

Sorry to hear that your viburnum bushes have a bit of a thrip infestation. Our resident DIY expert @EricL will be online later this afternoon, but in the meantime let me tag our great garden members @Noelle, @mich1972, and @LisasGarden to see if they have any suggestions. You can also learn more about caring for viburnums in Bunnings' How to grow and care for viburnum article.

Katie

Noelle

Hi @DIY_Dinkum

Have you had a positive ID of the thrips? Generally thrips appear as minute dark "slivers" on plants and they are most often attracted to light and white flowers and other white items (such as white sheets on the clothesline) over summer.

It would be really helpful if you could upload a couple of photos so we can rule out the possibility the pests are not thrips before advising on treatments. Winter pruning would not be something I'd suggest to eradicate them as they generally die out over the cooler months, re-emerging in spring from eggs laid in autumn.

Looking forward to seeing some photos of the insects please..

mich1972

Hi @DIY_Dinkum When you get a chance could you please post a couple of photos so we can have a look first to identify. Thank you 😊

LisasGarden

https://www.workshop.bunnings.com.au/discussion/comment/26052#Comment_26052

I done use any sprays in my garden including organic ones ( they can still have an adverse effect on good bugs) I am trying to get a good eco system happening. For the example we have had a lot of white fly and they are starting to naturally die off and some are being eaten by predators. As the problem is on your viburnum you can try hosing them off regularly and see if this helps. Good predatory bugs can also be purchased online. Who knew? 🤣 In my garden we have a lot of blue tongues and I haven’t seen a snail in years, nature is wonderful and although sometimes frustrating not spraying is beneficial . Here are a few of my critters that would be effected if I sprayed

lisaandlisa@lisasgarden instagram

@Lisa’s Garden Facebook

swallowtail will turn into a beautiful butterfly and loves munching on citrus

EricL

Hello @DIY_Dinkum

A photo would definitely help us to give you a better diagnosis. Unfortunately, thrips are very good at long term survival. Aside from laying their eggs inside the leaves, they also hibernate in the soil during winter. Once we see the condition of your plants our members should be able to get a better understanding of how serious the infestation is.

If you need a hand posting the photos, please let us know.

Eric

DIY_Dinkum

https://www.workshop.bunnings.com.au/discussion/comment/26055#Comment_26055

Great, thanks, I will do this over the weekend. I've been busy/offline for a bit, but have some spare time coming up.

We had a positive ID from our local garden center, but I'm happy to utilise my new phone's Marco-lens and get some images. I'll also get a few images of the condition of the bushes - it's also affecting our neighbor's bushes so we're of course worried that even if we fix the issue, if they don't it'll just rear its head again.

DIY_Dinkum

https://www.workshop.bunnings.com.au/discussion/comment/26072#Comment_26072

thanks Eric - I'll get some snapshots over the weekend. 🙂

DIY_Dinkum

https://www.workshop.bunnings.com.au/discussion/comment/75694#Comment_75694

Yeah, the Silver Eyes love eating the thrips, though unfortunately not enough to keep them under control. We haven't used any chemicals precisely because of the birds - we love watching them, and they've now made a nest in one of the viburnums 🙂

DIY_Dinkum

https://www.workshop.bunnings.com.au/discussion/comment/26055#Comment_26055

Hi @Noelle,

Better late than never eh! I've attached some photos.

We tried to control them when we first noticed them, but they're relentless and eventually overwhelmed the bushes. Almost every leaf is now infected.

Last season we chopped back every leaf, and it grew back really healthy and thrip free, but I suppose they emerge from the branches, and from out of the soil?

DIY_Dinkum

https://www.workshop.bunnings.com.au/discussion/comment/26059#Comment_26059

Thanks Mich, I've now posted up pictures elsewhere in this thread. Looking forward to your thoughts.

Noelle

https://www.workshop.bunnings.com.au/discussion/comment/76007#Comment_76007

Hi @DIY_Dinkum

The black insects appear to be thrips and you might be surprised to know that, while they may lay eggs on the bark of branches, most infestations occur through the pests flying in from surrounding areas where they have bred without any form of control.

The silvering of the leaves is an indication of thrips, and is also often an extremely good indicator that there are other sap-sucking pests around as well, such as **** mites..

There is no need to prune the trees back to within an inch of their lives - all you need is good pest control via insecticidal sprays, preferably natural or organic products. You need to be very persistent and vigilant and ensure both the upper and under sides of leaves are thoroughly treated.

Thrips and mites, like aphids, have a vast range of host plants that provide them with the shelter and nourishment they need to breed. Often these plants may be weeds in nearby parks or pastures. There's not much you can do about them in those locations but you can certainly aim to control them in your own garden by applying natural insecticides at least weekly during the warmer months of the year.

Child Item