Curl grubs in pot plant

[EllaCourtney]

Hi there! I have never had a home or garden until about 6 months ago, and have been delighted by a little cumquat tree I got from bunnings the week we moved in. It went from flowers to an abundance of fruit for its 3 tiny branches - but recently started looking a bit sadder and leaves were spotted with yellow. I decided to repot it (finally) and got some citrus potting mix. 

When I took it out of the original pot I discovered 4 fat curl grubs munching away on the roots! I was horrified - but after checking there were no more, continued to put it into the new pot and soil. I later read on google that maybe I should have rinsed the roots to make sure there was none of the 'infected' soil left attached, and discarded the original soil. Is that right?

TLDR: Curl worms discovered when repotting - should I chuck the whole lot out now and get new soil?!

Community manager's note: Check out How to control curl grubs and army worms for expert advice.

Would love your help with this! 

[MitchellMc]

Welcome to the Bunnings Workshop community @EllaCourtney. Many thanks for your question, I'd be happy to assist.

It's great to have you join us and I'm sorry to hear about your curl grub issue. I am not aware of any chemical treatment on the market that is tested and suitable for use with food crops. My advice would be, as you have mentioned, to bare root the plant and change the soil out completely. The issue with leaving the soil is that the juvenile stages of larvae can be undetectable. This year Queensland is having a horrible season of curl grub infestations and our suppliers have been having trouble keeping up with the demand for lawn products. 

Let me mention the wonderful @Noelle to see if she might have some alternative methods for control to share.

Please let me know if you need further assistance or have questions.

Mitchell

[Noelle]

Hi @EllaCourtney and @MitchellMc 

Because it is a citrus, I would be reluctant to 'bare root' the plant to ensure there are no grubs or eggs remaining around the roots. Citrus have surface fibrous root systems and deeply resent root disturbance. So rather then remove all traces of potting mix from around the roots, I'd try a soil drench of ecoOil or neem oil, both of which can be safely used for the treatment of edible plants. Read the labels for instructions on how much to use per litre or bucket of water, mix it well and pour into the potting mix until excess drains out the base of the pot.

The curl grubs possibly found their way originally into the pot through drainage holes - stand the pot up off the ground on pot feet or some bricks to prevent this happening again.

The other way they can enter potting mix is if an opened bag of mix has been stored outdoors or on the ground where the grubs or the adults may have access. If you have to keep an opened bag for short period, make sure to put it in a shed and up off the ground and fold the top over securely.

[EllaCourtney]

Thanks so much @Noelle for this advice (and @MitchellMc for the referral!)  - I ducked up to bunnings this afternoon and got some eco-neem oil, so hoping I'll be able to decipher how to use it tomorrow. On the back it seemed to focus on just spraying the leaves, couldn't see any soil-drench instructions but i'll google it

And great tips on the curl grubs. I felt so invaded when I saw them! Will be doing my best to fend them off from now, cheers!

[MitchellMc]

Hi @EllaCourtney,

The product is predominantly used for insects on leaves, so they are concentrating on that for the instructions. @Noelle has given some advice on her mixing method. I believe she was mentioning the concentrated version of Eco oil which you mix up with water so you can pour it through the potting soil.

Mitchell

[paulcortes]

Hi there 🙂

Just wondering what does the eco oil drench do to the curl grub?

[Plant-A-Holic]

Hi Noelle

Curl Grubs are as said very prolific and the damage if not caught early usually ends poorly for the plants. I agree with the excellent advice on dealing with Curl Grubs a rather ugly grub. I was told about Neem oil and has been a great benefit in getting rid of the Grubs. Thank you for your other advice I will certainly be rearranging my potting and similar items of the ground.

🙋🐨 Tricia

[Jason]

Welcome to the Bunnings Workshop community @paulcortest. We're so pleased to have you join us and look forward to reading about all your projects and plans for around the house and garden. Please don't hesitate to post anytime you need a hand as we're sure you will get plenty of helpful information, advice and inspiration from our amazing community members.

Let me tag @Noelle for you so she is alerted to your question about what the eco oil drench does to the curl grubs who have invaded a pot. 

Thanks again for joining in the discussion.

Jason

[Noelle]

Hi Paul (@paulcortes) 

Using eco Oil or Neem Oil will have the same effect.  They both act as natural insecticides that kill insects (for example the beetles that lay the eggs that result in curl and other grubs) and their eggs, as well as suffocating the grubs.  They are both oils that prevent the grubs from breathing, thus killing them.

Both products are environment friendly and will not harm plant roots or the soil/potting mix that you are treating.

[Vicky2]

I also have this problem with pots that I have raised of the ground and also pots that are hanging. I get so deflated as I use really good soil.

How do I stop them in my hanging pots?