How to control thrip long-term?

[DIY_Dinkum]

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.

D

[DIY_Dinkum]

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

[Noelle]

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 spider 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.