How fast has the beetle attacked the world?

The major invasion of Spain started in 1994 apparently in diseased palms imported from Egypt. Other invasions include Saudi Arabia 1985, Portugal 1996, France 2004, Canary islands 2005, Balearics 2006, Malta 2006, Italy 2006, Greece 2006 and California 2010. Imported trees from Asia have apparently accelerated the problem in a number of these countries.

One beetle can lay around 200 eggs every ten weeks, and these produce larvae which become mature weevils after seven to ten weeks. The grub like larvae eat the inside of a palm tree for around a month before exiting from the trunk through a small tunnel to form a cocoon at the base of the tree before transforming into an adult beetle. At first it crawls but once dried out in the sun, as a butterfly does, it is said to fly up to five kilometres!

How to detect palm weevils & beetles in your palm trees?

There are several ways to detect the palm beetle and its larvae. Look for crawling weevils around the base of a palm. You can see them in the leaves if stood on a ladder.

You can actually hear the crunching noise of the eating grubs through the bark of the trunk of the tree. Look for chewed wood and a viscous smelly liquid coming out of holes. There is a fermenting smell in the area of a palm tree and of course dying fronds on top of the trunk.

Controlling & Curing the Palm Weevil

Naturally this depends on how early in the life cycle you notice the problem. If you sprayed or injected insecticides into the trunk as soon as a weevil has just laid eggs or the eggs just hatched out as small grubs you would have a chance of curing the problem.

But if you can hear grubs through the trunk it depends how much of the soft core of the trunk has been eaten. Two or three hundred grubs each eating and chewing  a tunnel up to a metre long  will soon take a palm tree beyond the point of no return as the palm will not be able to draw up and transport moisture and nutrients from the roots to the crown of the palm. This situation can be reached before there are any signs of dying fronds at the top of the palm.

What Types of Palms are Affected by Weevils?

In the main it is the Canary Island palm ( phoenix canariensis) and the coco palm (phoenix dactylifera)  but there are cases of Washingtonias and others  also being affected. It has been suggested that if weevils run out of their favourite palms to eat they will move onto other palms to survive. To date dwarf native palms Chamaerops humilis have not been reported as being affected. Recently planted and badly pruned palms are at most risk.

The Way Ahead

We can only suggest that you are doubly alert to the risk to your palms and take precautionary preventive actions using qualified licensed persons.  Move fast  if problems are observed and plant no further palms in your garden. If you suspect you have a problem with your palm trees, we would strongly recommend that you contact us immediately as our trained pest control professionals can provide a thorough inspection.