Asian Ambrosia Beetle - Control

I wrote in 2001 about my travails with a flowering cherry tree in my back yard. It was a large one and my wife had noticed that half of it was completely dead. I vowed to wait a bit longer to see if anything further happened to the tree.

I’m glad I did! Jerry Allen, of Organic Landscape and Design, was visiting me last week when I asked him to examine my cherry. “It just up-and-died!” I exclaimed, walking toward it. “I can’t find a single cause.” Arriving at the tree, I slapped the trunk for emphasis. Sawdust poofed from beneath my palm. Surprised, I looked more closely at the bark.

Oh no! Protruding from it in a dozen places were tiny “toothpicks” of sawdust: the tell-tale sign of an Asian ambrosia beetle attack.

I’d mentioned the pests before but had not yet seen them on my property. The tiny female beetle bores into the trunk of susceptible trees (crape myrtle, redbud, dogwood, cherry, etc.) and deposits her eggs. Lovingly she leaves a deposit of ambrosia fungus in the hole, to provide a first meal for the larvae when they hatch. Unfortunately, the beetle fungus is usually contaminated with other, more virulent, fungi - which often lead to a tree’s demise.

There is no treatment for an Asian ambrosia beetle attack. The fungus inside the tree can not be eliminated. The attacked side of my cherry tree died and the other half died in 2003.

Asian ambrosia beetle is serious pest. Once it attacks a tree the only treatment is to cut the tree down. Crepe myrtles might resprout and grow another trunk to replace what you remove but most other trees do not respond so nicely.

If you notice the "toothpicks", your best bet is to spray susceptible trees each spring with cypermethrin, permethrin or deltamethrin in order to protect them.

To know when to spray, you can build a trap to monitor their emergence in early spring.

Ambrosia Beetle Trap

Ambrosia Beetle Life Cycle