Invasive beetle causing big problems on the Big Island

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Half of Brooks Maloof’s trees were killed due to a pest. Maloof owns an orchard in Puna on Hawaii island. He said it started with a healthy avocado tree about a month after he purchased some mulch.

“We had a load of macadamia nut mulch that we’ve been using for years around our trees. The batch came in and I had the person brining the mulch, this is macadamia nut mulch, compost. A ball of soil was shoveled out of the truck and I saw all these crawly things in it and I wasn’t sure if it was termites or what,” explained Maloof.

He said he sprayed it with Raid and forgot about it. Until his avocado tree, about 20 feet from the mulch started dying.

“A fully loaded hass avocado tree started to drop its leaves and the fruit and I saw some drillings in the trunk of the tree, but I kind of gave up on that tree. I thought something got it that was pretty powerful,” said Maloof.

Then several months later he noticed his citrus tree were showing similar signs.

For more information about A. aesthetica go to 

The culprit is likely a type of longhorned beetle discovered on the window screen of a resident in Hawaiian acres on the Big Island in 2009.

“The longhorn beetle is called Acalolepta aesthetica and it’s from, its native to Australia,” said Darcy Oishi, the biological control section chief of the department of agriculture.

Oishi said although they’ve collected a number of specimens of the years,  they still know very little about A. aesthetica since it doesn’t cause this type of damage in Australia.

“It was found at large, we didn’t know what it was doing, we couldn’t get an ID,” said Oishi.

The beetle lays an egg and when it hatches the grub bores through the tree creating tunnels in the trunk.

“It causes a lot of boring damage. It will bore into wood and create wounds that will weep and basically weaken the plant and make it open to more infections by diseases and more vulnerable to death,” explained Oishi.

The drilling often leaves sawdust fragments outside the hole.

There are only a handful on plants officials can identify as hosts including: the kukui nut tree, breadfruit, various citrus trees, Queen Sago palm and cacao trees.

Other plants it possibly affects are the gunpowder tree and avocado trees.

“Normally if an insect is specific. It will hit tribes or sub tribes of plants. This isn’t the case with this one. It’s across the board,” said Oishi.

And that is what makes it so difficult to control. 

There are already 500 cacao trees infected on the Big Island and farmers are afraid.

“Left unchecked it could devastate everybody’s orchards if nothing is done,” explained Patrick Merritt, the East Hawaii cacao association president.

He said at this point the beetle is only on three farms but, “it could get worse cause there’s a whole bunch of farms around here that haven’t got the beetles yet, but guarantee it’s coming.” 

The big question is: how do you get rid of it?

Officials said, they don’t know how to control it yet.

“There’s a lot of research that needs to be done. How to find it. How to kill it, especially since the crops that are affected are food crops. There’s a lot of work that needs to be done yet. The department is looking into all of those issues now,” said Oishi.

Merritt had a suggestion on how to deal with the problem. 

“On Oahu they have the Rhinoceros beetle. The state or the county puts in funds and they have traps everywhere. I think that’s what we need to do here because the beetle could just really ravage everybody,” Merritt said.

The full economic impact of is unknown at this time and officials said it’s impossible to know how much damage it could cause until they learn more about the beetle.

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