Arbor-wellness: South American Palm Weevil

Why do so many palms look like they are dying? It seems like the top fell off and only the side leaves are left.

This is a sign of a new pest species invading the southern California region called the South American palm weevil. It is a large, black insect that deposits eggs in the top of the palm tree. The larva eats through the main upper part of the palm tree, eventually killing it. 

Will it affect all palm trees?

The primary palm it invades is the Canary Island date palm. However, other palms, including our native California fan palm tree, are possible targets as well. We are carefully monitoring this situation with all palms just to be prepared.  

Will it spread to other areas?

This large insect is a long distance flyer. Studies indicate it can fly as far as 15 miles in one flight. It was only present in southern parts of San Diego region a few years ago but has spread further north and east as it expands its range in the US. It has also started to become a problem in other southern states with Canary Island date palm populations. 

I see black round plastic boxes by some palms, what are those?

White or black weevil traps are being set in areas to help determine the spread of the insect to new areas. This helps determine how quickly it is spreading into new areas. 

Can you do anything about it?

There are controls for this insect, but they are only effective when preventing an attack or very soon after that. We know that if your palms are healthy, watered correctly and not otherwise having problems, the current control measures will be more effective. Because this seems to be a serious pest problem, avoid planting new Canary Island date palms in the future.  

When should I remove an affected palm tree?

If you suspect your palm might have this insect, contact your Arborwell arborist right away. We can determine if your palm has this insect and safely remove and dispose of those that are affected.  Remember they kill a palm quickly, so being proactive with protection of prized trees is important for their survival.

If you are concerned about the South American palm weevil and want to schedule an inspection, fill out the form below.