alentejo monte

Buying an Aljezur farmhouse

Aljezur farmhouses for sale

Algarve west coast climate; the best weather in Europe?


Odeceixe beach

Control of the red palm weevil

Vicentina natural park wildlife

Heating options

The truth about coastal property

What is natural park Costa Vicentina?

Building and renovating in western Algarve

Portugal land scams

Fishing on the Vicentina coast

Western Algarve agriculture


Utilities in Portugal

Schools in Aljezur

 Solar home heating plans
DIY control and prevention of
 The Red palm weevil, Rhynchophorus ferrugineus Olivier
How to affordably treat and preserve your palm trees in the Algarve or other places
red palm weevil
If you spot even 1 of these near your place, take action immediately.
healthy canary date palm, algarve
A healthy canary date palm in the Algarve, Portugal. Note the tall top leaves, equal in length to the horizontal ones, giving a ball shape.

I've found it pretty difficult to get information in English relevant to the local situation here, so here's what I've found out so far.

The red palm weevil has streaked across the Algarve, and is already north of Aljezur and likely into Alentejo [April, 2011].
By the time you see symptoms in a tree, it's probably too late to save it. The tree simply shows no outward sign until the interior is nearly consumed. When it dies, thousands of weevils spill out, and fly away to infect more trees. A Weevil can fly up to 8 km.

But if you're willing to spend the time and money, you can prevent the initial infestation; you can save your trees.
For how to prevent infection with chemicals, click here

Pesticide sprayers and pumps

Another important thing is not to cut off the leaves [as is a popular fashion here].
There are 2 reasons for this; the first and most important is that the smell from the freshly cut live branch is a strong attractant for the weevil. And the cut leaves a handy soft spot for them to burrow into.
The second reason it that it weakens the tree; the horizontal leaves are getting the most sun and doing the best work. Cutting off the most vital and healthy leaves stunts the growth According to renown palm expert Robert Lee Riffle in his book "pocket guide to palms";

Unfortunately, many palm owners or the landscapers they hire go far beyond these pruning practices; they remove enough leaves to create leaf crowns that look like feather dusters or shuttlecocks, leaving only the most erect, living leaves. This abominable practice completely ruins the wonderful appearance of this species. It is also inimical to the overall health of the tree which must struggle to photosynthesize enough food to maintain itself.
shuttlecock palm
typical over-pruned tree

Common advice is, if you must cut the leaves, cut 1 meter from the trunk, and if you cut into any living fiber, cover the wound with a pesticide and/or sealant.
Another good idea is to prune at the coldest time of winter, because the weevils don't like cold and are less likely to be out hunting.

The Portuguese authorities aren't doing anything about this situation as far as anyone has heard so far; in other countries where the weevil has been a problem for decades, it's been beaten back until it isn't necessary to treat all the trees all the time.
Instead, there are monitoring traps maintained by the agriculture departments. When weevils are found in an area, treatment is started in trees there until no more weevils are detected.
This has to be done over really large areas, hundreds of kilometers, to be an effective strategy. Until a program like that is launched, it's everyone for himself. Pay, spray, and pray, or lose you trees.

There is a biological defense as well, a nematode that eats the weevils.
This is bought in frozen blocks of live nematodes [tiny worms].They only eat weevils supposedly.
I don't think they're practical for the DIY user, since you need to keep them frozen until use, then keep them in an agitator tank as the solution they're in is pumped into the tree.

I'm very open to sharing information on this subject, so if you have anything to add, please let me know.

first signs of palm weevil infection
This tree is showing signs of an early infection; note the chewed off leaves. This happened inside the trunk before they even sprouted, so a few months before the photo was taken. Hopefully, this tree is being treated now.

The tree below shows classic signs; the diamond cuts to the leaves where they were eaten during their formation.
tree eaten by red palm weevil

For how to prevent infection with chemicals, click here

Pesticide sprayers and pumps