Larvae in Cotoneaster horizontalis bark

[Bajro-san]

Hi everyone!

I was cutting some dead branches of my Cotoneaster horizontalis today and found a larva (presumably) in its bark. I've dug it out with some wire and took a picture of it.


Could this be the cause of the branches dying off in the first place? I was hoping that someone could help me identifying it and any tips about how to get rid of them would be highly appreciated. I've done a short Google search and I'd say that it resembles weevil larvae a lot, but since those are typically found in the roots, I am not sure this is the case. Could it be a larva of some kind of a borer beetle?

Thanks for your time,
Bajro-san

 

[Firstflush]

Yes it could be. There are likely more. Some sort of bark boring beetle larva. Im typically against systemic pesticides but you will need them in this case. The plant uptakes the insecticide with the fertilizer and kills off what’s eating it. Bayer makes good products but they may not be available where you live. Add your locational info to your profile so people can help you more.

 

[Wires_Guy_wires]

Unless the larvae are in dead wood. Dead wood doesn't transport water, so it doesn't transport insecticides either.

A chicken-egg kind of thing unfortunately. If possible, find a tunnel and trace it to where the larvae have been feeding; if it hits live tissue, you're going to need systemics. If it's dead tissue only, then systemics wouldn't work.

Do keep an eye out for sawdust and other traces. Borer beetles usually fly out in spring or summer and deposit eggs not much later. Sometimes in early fall. Those are the best times to be preventative and keep an eye out. I check for sawdust and holes throughout the fall and winter.

For Europeans, where systemics are off the market for consumers and a lot of professionals, it's harder to combat beetles and their larvae. But there are loopholes: some sprays used for silverfish for instance, are legal, and they contain the same insecticide as some beetle-systemics that are illegal.

 

[leatherback]

some sprays used for silverfish for instance, are legal, and they contain the same insecticide as some beetle-systemics that are illegal.

Never knew that. Good info.

I got beetle larvea to vacate the trunk by pouring alcohol in a boring hole.

 

[Wires_Guy_wires]

Never knew that. Good info.

I got beetle larvea to vacate the trunk by pouring alcohol in a boring hole.

Also works against wood lice. Might save a couple air layers and cuttings that way.

 

[Bajro-san]

Thanks everyone!

@ Firstflush
I've added the location now, sorry, thought I had done that already

@ Wires_Guy_wires
How would one use that spray then, mix it in the water? Also, could you tell me which sprays I could use or which insecticide I should look for?

@ leatherback
This sounds as a simple enough method, I'll inspect the tree for further boring holes and give it a go.

 

[Wires_Guy_wires]

I can tell you which spray you'll need to use if you can positively identify the larvae.
Some beetles are not susceptible for some insecticides. Identifying beetles is difficult, especially since I don't like reading Austrian/German and I don't know the local species and/or literature.

If you can identify it, then go to google scholar and type in 'treatment + animal name' or 'prevention + animal name' or 'management + animal name' or similar search terms. There's usually a list by some forestry or agricultural agency that explains which insecticides are effective. Look for the active ingredient, and see if there's some kind of spray or pellets that are available for you that contain that active ingredient.

Some insecticides don't mix with water, so they need a carrier. But that's something to think about after positively identifying the animal and devising a strategy.

 

[Firstflush]

WGW, if the borer was under deadwood/bark, wouldn’t it still be likely the pest may be eating live material.

 

[leatherback]

WGW, if the borer was under deadwood/bark, wouldn’t it still be likely the pest may be eating live material.

Yes. Quite.

 

[Yosemite Goat]

Some larvae eat heartwood, so sytemics might help and might not.

 

[sorce]

Welcome to Crazy!

That was quite the delayzy!

Sorce