How to stop gall wasp on lemon tree?

[Isobel]

Hi everyone.

We have gall wasp in our lemon tree. We’ve been repeatedly cutting it out over the years but it keeps coming back! I just want to let my poor tree grow!! Do those yellow pest strips actually work? Or anything else other than severe pruning?

Keen to hear everyone's tips. Thanks.

[Jason]

Hi @Isobel,

I’ve chatted to horticulturists about this problem as we have had difficulties with the wasps too and they recommended the pest strips. They are also inexpensive so certainly worth a try. They are a lot less invasive than harsh pruning.

I am interested to hear other people's experiences. 

Jason

[bluebec]

Hi @Isobel

Citrus Gall Wasp is a big problem in Melbourne (and Australia).  They keep coming back because you'll have neighbours somewhere with the same problem - and they may or may not be addressing it.

http://www.abc.net.au/news/2015-09-04/save-our-citrus-group-campaigns-to-rescue-melbourne-lemon-tree...

I'd recommend talking to your neighbours and getting them to talk to their neighbours and so on so you can try and eradicate it from a wider area.

[Joker]

I've given up cutting it out, pruning seemed to be hurting the tree too much and we went years without getting any fruit. The trees seem to cope OK now.

Joe

[Eric]

The yellow strips seemed to help a lot for my little trees.  I also used a scalpel and chopped off any I saw if it was still a small lump.

[timjeffries]

Definitely use the strips. You must also cut it out though. If you leave it the new ones hatch and it keeps creating the problem. Need a neighbourhood campaign to really get rid of it.

[Isobel]

I've finally got around to getting some strips. Will let you know how I go with them.

Thanks for the advice. 

[RosieW]

I slice the top of a gall and the eggs die, but that only works if I keep at it. I have never heard of those yellow strips - thanks going to try them. 

[Isobel]

How's everyones citrus going? I'm perservering with both the yellow strips and cutting it out, but without the heavy pruning of previous years as I want as much fruit and growth as possible. Still an ongoing battle! 

[Stephen-H]

Hi @Isobel, I worked with an Entomologist a few years ago on a citrus gall wasp (CGW) trial with interesting results. The trials are still ongoing and are directed to the citrus industry so have chemical levels in fruit in mind for export.
A product called Surround Koalin Clay was trialed on moderate to heavy infested trees with good results and a number of systemic chemicals were sprayed and also applied via drip, with ranging results.
https://www.citrusaustralia.com.au/news/latest-news/protective-spray-reduces-gall-wasp
https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0004/340609/citrus-gall-wasp-in-southern-australia...
https://www.dpi.nsw.gov.au/agriculture/horticulture/citrus/content/insects-diseases-disorders-and-bi...
Parasitic wasps were also released with good results long term.
Confidor Guard was the the most outstanding preformerthrough the drippers. I am not sure what the outcome of the application to the APVMA for licence to use it on citrus is though.
Guard is expensive and the smallest container is 5lt. I have used Confidor (not Guard) this year at 16ml per tree watered into the ground in late october and have noticed that most of the galls are still intact

http://horticulture.com.au/wp-content/uploads/2017/05/Strategies-to-manage-citrus-gall-wasp-%E2%80%9...
This page shows the results of the trial while i was involved
In the Sunraysia Lemon trial the reduction of galls with the Confidor Guard was visually noticable from one year to the next.
Hope this helps