When I told Cruella (my wife) that I had to rush out a special Palm weevil post by popular demand, she just curled her lip and scornfully replied “it’s only a bloody beetle get over it”. I hope this conveys some of the pressure I face on a daily basis. I would leave her but she is holding the garden ransom, and on a number of occasions she has threatened to curse the ground so nothing grows. All of this may seem strange especially as she is our local Church Warden, but I think she is working undercover.
7th April. Things I have been doing lately:
🪳 Dealing with Palm weevils. First some background. The red palm weevil first arrived in Spain in 1994 probably in a cargo of trees from Egypt. Since then it has rapidly infested Spanish Phoenix palms. At the moment it appears not to attack Washingtonia palms in Spain but it has been known to do so elsewhere. In the main it will attack trees under 20 years old but not exclusively.
The adults will cause a certain amount of damage by feeding, but the main damage is caused by the larvae. The adult female lays up to 200 eggs at the base of the fronds in the crown of the tree. When these hatch, they merrily munch their way up the inside of the fronds, eventually resulting in the fronds collapsing and the tree dying. In a severe infestation you can put your ear to the trunk of the tree and hear the grubs feeding. The first photo below shows the enemy. The second shows some of my palm trees and explains why I need to be careful.
🌴 Preventative treatment for palm weevil. When you first arrive in Spain, no matter how good a gardener you are, you are not prepared for the palm weevil as we do not experience it in Northern European. When you lose a palm you are distraught, so it is important to act quickly. If the tree is relatively low, or you can reach the crown with a short ladder, then you can spray the crown and this should act as a preventative.
If the tree is large then you need to either bring in professional sprayers every couple of months, or devise a method that can deliver chemicals directly to the crown of the tree. I have devised and revised a method over the years that works for me, so please feel free to copy the system described below.
🥷 Preparing the palms. At its simplest this process seeks to deliver the chemicals into the trunk of the palm which the rising sap will then take up to the crown of the tree and infuse the fronds with weevil killing chemicals. Over the years I have refined and revised my methods. But at the heart of the process is to drill a hole at a 30 degree angle half way into the trunk round about a metre from the ground. You then need to insert a piece of simple irrigation pipe into the hole. The hole and the tube is at this angle because you don’t want the chemical dribbling out and also you want to keep a gravitational pull on the chemicals so that they constantly feed into the tree. (I hope that doesn’t sound complicated, as it is not).
The first photo below shows my original version. Here, I wrapped tubing around the tree that acted as a reservoir for the chemicals as they were fed into the tree. This could drip feed the chemicals over a period of three months. Cruella (my wife) put an end to this system when she encouraged a pack of rabid red squirrels to eat my weevil tubes.
The next photo shows my anti squirrel revised version whereby I ditched the reservoir and instead had a simple perforated tube inserted into the trunk which could be topped up each month. The final version is my new deluxe minimalist weevil killer (top of the range). This has a short piece of tubing just to fit into the tree. Note that each version has a cap at the end, this is to stop anything else getting into the tree. Make your own one up or just stick a bit of rag in there.
The final photo shows the weevil system in place. I am showing how far to drill into the trunk and you can see the angle from the cap. By the way the holes I appear to be pointing to are nothing to do with weevils, this is where the palmista who cuts the trees sticks his spiked boot into the trunk. Click on each photo for a larger view.
🧪 The equipment. All the equipment is very cheap and can be bought in any local gardening store. The photos below shows the basic equipment and mixing method which is simple. Click on each photo for a larger view.
- a proprietary weevil killing chemical that can be diluted
- a measuring jug to make sure you get the right amount of water (in my case 1 litre)
- a garden syringe to measure out the chemical before adding it to the water
- an old Fairy Liquid bottle needed to squirt the chemicals into the tree
🤺 The process. Once you have mixed your chemicals, then how you use them depends on the palm size. The first photo shows my trusty Fairy Liquid bottle being used to squirt liquid into the trunk. This method is used for high trees where you cannot get to the top.
The second photo is the method used for small trees. Just use your Fairy Liquid bottle (other brands are available) to squirt the chemicals on to the base of the palm fronds. This will act as a deterrent to the adult weevils.
The final photo is the process for those trees that are just a bit too big to get at easily. You could get a ladder out, but you can’t be bothered. Just squirt the chemicals up into the base of the fronds. Don’t do this on a windy day and if possible wear a mask. Many a day I have weevil proofed myself and it doesn’t taste nice.
😥 Don’t despair if you lose a palm. I lost two palms when I first arrived in Spain and I was of course upset. The thing to do is don’t just chop the tree down and leave an unsightly trunk shaped root sticking up in your garden. Nor should you try and make a table out of the palm by chopping it back and placing a table top on it. The resulting table will never be in the right place and you will eventually abandon it.
Instead, what I did was to get the palm chopped back to about 12ft. I then wrapped mesh around the trunk and grew climbers up its length. This gives a spectacular display of flowers all summer and is a joy to behold. The photo below shows my dead palm tree brought back to life.
I hope all of this helps. Let me know how you get on.