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By Rhysw

wellington, New Zealand Nz

My Thuja is not looking healthy.
The leaves are matting up with dead material. I am pruning them out but is that going to be enough? Is it a fungal infection and how do.I treat it ? Any ideas most appreciated as I have a bunch of them in a row and the two largest are affected.

Img_20180131_100147 Img_20180131_100141 Img_20180131_100301



It looks like the beginnings of a bagworm infestation. If so, those clumps of dead twigs should contain a caterpillar, during the day. At night, they come out to feed.

31 Jan, 2018


Be sure the roots aren't too wet & perhaps a more exposed location would help it along. It seems very sheltered. Wind, snow & sun will get rid of those suckers.

31 Jan, 2018


Actually it's quite exposed to wind (no shortage of that in wellington) and we've had plenty of sun this summer. It sounds like if I keep an eye on cutting out all those matted areas I'll get rid of the caterpillars. Thanks for the id.

31 Jan, 2018


Hopefully, but its unlikely the trees will fill in the gaps again.

31 Jan, 2018


The bag worms have now spread to some other thujas I have. Does anyone have any suggestions as to the best spray to get rid of them. I have tried picking off all their cocoons but they keep coming back (possibly from other trees on neighbouring properties)

25 Jun, 2018


Here in the States, I would recommend spinosad or Bacillus thuringiensis kurstakii, but I don't know what is legal in the UK.

25 Jun, 2018


I heard a lot of positive things about spinosad. I hope I never have to use it.

25 Jun, 2018


Thanks for that. I'll see if I can get it and will give it a try (I'm in New Zealand)

28 Jun, 2018


Oops! Sorry, Rhys! Somehow managed to read it wrong, but I don't know how. Maybe it's time for new glasses. 8)

29 Jun, 2018

How do I say thanks?

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