How to control white wax scale on my Lilly Pilly hedge?

[andygpage]

Hi! Our Lilly Pilly hedge has an infestation of white wax scale. In desperation, I’ve been using a high water pressure hose to dislodge them from the tree. I’ve been applying Pest Oil to the plant, but hasn’t seemed to work. There are thousands of these suckers riddled throughout the hedge, and it’s obvious that it’s in some distress. Is my hosing method a valid approach? I’m keen to get a horticulturist come over to our place to assist with recommending a more heavy application of pesticide, but can’t seem to find this service. Does it exist? Any help / advice sincerely appreciated. Here’s a pic of some of the plant for reference. Cheers, Andrew

 

[MitchellMc]

Welcome to the Bunnings Workshop community Andrew @andygpage. It's sensational to have you join us, and many thanks for your question about controlling wax scale.

Fortunately, you've come to the right place! We have knowledgeable horticulturists and plenty of gardening enthusiasts within the community.

You've got a significant outbreak there, and hosing them off or trying to control them by hand won't be very effective. The Pest Oil won't remove the white globular clusters, but it should help control the situation. If you feel it's still out of control, I'd recommend turning to Yates 750ml Ready To Use Scale Gun Insect Pest Killer. It includes pyrethrum and white oil, and is the next step up from using Pest Oil. You need to wait for some clear weather and spray the top and bottom of the foliage.

Let me mention one of our horticulturalists, @Noelle, to see if she has any thoughts.

Please let me know if you have any questions.

Mitchell

[Noelle]

Hi @andygpage 

Using a combination spray as Mitchell has suggested is the next step. The white oil aids in dissolving the waxy scale (as well as smothering the pest underneath the wax cap) while the pyrethrum will also kill the pest.

It's essential to get a good cover over affected areas, making sure to spray the undersides of leaves and along branches as well as on the upper surfaces of leaves where the scale may be more obvious.

Repeat in 10-14 days to ensure good control.

[andygpage]

Thanks both. It’s a very large hedge … can you buy in larger quantities? 

Also - they are not evident on the leaves at all … only the branches. Should I not worry about spraying the underside of the leaves then? It’s a really big job so just wanting to make sure I hit the right spot. 

Cheers, Andrew

[MitchellMc]

Hi Andrew (@andygpage),

Scale gun isn't available in larger quantities. Alternatively, you could do an application of white oil and then pyrethrum. These come in concentrated forms. You'll need to spray the entire plant, including the top and bottom of the leaves.

Mitchell

[Littlecastle]

Mitchell, 

We have the same problem. Our hedge measures over 250m in length and 5m in height and in all honesty we'd be spraying for days. Is there a product that we could put around the roots that the plant will absorb that could do the same job?

[EricL]

Hello @Littlecastle 

That's an excellent question, let me make some inquiries regarding root-based application of white scale herbicide. I understand that it might seem daunting to spray such a large area, but I propose investing in a good quality pressure sprayer with a wand. This will at least help you in spraying such a tall hedge. Concentrated pest oil such as Yates 500ml Pest Oil Concentrate will allow you to make several litres of herbicide spray and cover a large area.   

In the interest of health and safety please make sure to wear disposable overalls and personal protection such as gloves, goggles and an appropriate mask when using the spray. Please make sure to follow the safety instructions printed at the back of the product.

Eric

[Littlecastle]

In which order should you spray if using the two separate products? Oil or pyrethrum first?

Can you make your own mix of the two in one spray pack or do they have to be sprayed on separately?

Thanks for your advice.

Littlecastle

[MitchellMc]

Hi @Littlecastle,

I'd recommend spraying the Pyrethrum first and then the White oil or Pest Oil. The White oil will prevent the Pyrethrum from contacting the scale.

Mitchell

[MitchellMc]

Hi @Littlecastle,

I am just following up about the root-based application method, and unfortunately, I haven't been able to find any products that would suit your needs.

Sorry, I also missed your question about combining the products. I would spray them separately and as per instructions on the packaging.

Mitchell