How to treat longicorn beetle borer?

[lillyhb]

I've got two very young apple trees (<1m tall each, main trunk ~5cm diameter) that have a lot of longicorn beetles over them (~20 quick count). We've had a week of rain and I didn't notice them before that but saw them yesterday for the first time. I'm confident in the type of beetle but haven't had a lot of luck googling treatments. I'm assuming some kind of insecticide. Based on flowering time, I'm expecting the fruit to be ripe end of Jan -mid Feb so ok if longer holding period. There are only about 3-4 fruit per tree as they're young trees and I don't want to put too much weight strain on the branches but am hoping to have 1 or 2 pieces of edible fruit for our first season 🤞

Thank you

[MitchellMc]

Welcome to the Bunnings Workshop community @lillyhb. It's wonderful to have you join us, and many thanks for your question about controlling Longicorn beetle.

I am not aware of any products suitable for controlling Longicorn beetle. The best preventive action is to ensure your trees are healthy, making them more likely to survive an attack. Here's a helpful article: Borer control in your garden. 

I suggest physically removing the beetles from the plants with gloved hands and disposing of them. Let me also mention a couple of our knowledgeable gardening experts, @Noelle and @mich1972, to see if they have any thoughts.

Please let me know if you have any questions.

Mitchell
 

[Noelle]

Hi @lillyhb 

'd agree with @MitchellMc  That the best approach would be to physically remove and 'relocate' the beetles to a place other than your garden! It's the larvae of the beetles that are troublesome as they bore into the wood of trees and can cause significant damage.

The adult beetles can fly so using chemicals to control them is not going to be terribly practical.

Removal before the adults lay eggs and larvae hatch is the best approach.

Be vigilant and remove any beetles you see - check the trees every day or so. Thee beetles are most active over warmer weather.

[mich1972]

Good morning @lillyhb my understanding with borers is the grub / larvae does all the damage as it bores through the trunk / branches. But borers only really attack unhealthy or dying trees. I don’t think you can really spray for them correctly. Just ensure that the trees are really looked after and healthy should help. I agree with @MitchellMc and @Noelle @with the good information they have shared.