Fighting the Red Palm Weevil

Here, Bob Wright provides us with the following update about the ecological threat posed by the red palm weevil which is causing considerable damage to palms across the Mediterranean. Bob writes: ‘PREVENTION is the only option – there is no cure!!

Half of the palm trees in Heraklion sea front have apparently been destroyed. The weevil has spread to Atsipopoulo just West of Rethymnon. Remember that it is not just the Canary palm, Phoenix canariensis, but others such as the tall Washingtonia which can be attacked. First we need to understand the life cycle: The adults are 3 - 4 cm long , red brown with a long muzzle, but they do not directly harm the palms; it is the LARVA / CATERPILLAR which emerges from the eggs laid by the female who is the enemy. She lays up to 300 creamy white eggs in the base of the young leaves on the underside at the top of the palm, by drilling holes with the muzzle .The caterpillars are 5cm long, (larger than most) and these feed on the soft fibres inside the heart of the palm, which is the only growing point. Apparently in a bad infection, you can hear them munching away! After about 2 months of feeding, they make a cocoon form the palm fibres, in which the PUPA/CHRYSALIS develops for 14 – 21 days before the new adults emerge. So the whole life cycle lasts about 3 MONTHS, but one can find all stages in the same palm if there have been multiple infections.

Symptoms of Infection: The stages of the weevil itself are difficult to spot because they are inside the palm. Careful observation of the underside of the young leaves may reveal the drill holes of the female. Next the young leaves die and hang down like a BROWN UMBRELLA. Already it is TOO LATE to save the palm. You should notify the authorities or tell your local garden centre. The trunk then must be cut down, the leaves burnt, and the trunk should be sprayed with insecticide and then buried 2m underground. If this cannot be done, then the leaves should be and tied up tight with a plastic net. CONTROL- a 2 pronged attack OUTSIDE – Spray with the base of the young leaves , on both sides with CYPERMETHRIN (chemical name) sold as Reldan. It is a synthetic pyrethroid , often found in ant sprays, which acts as a neurotoxin to insects, so it is there to kill the FEMALES. It has a low toxicity to birds and mammals but is highly toxic to bees. Excessive exposure to humans can cause nausea and headaches. INSIDE- Spray heart of palm with IMIDACLOPRID (chemical name) which sold as Confidor. This is modified nicotine and has a low toxicity to animals other than insects, but again is very toxic to bees. It will kill the caterpillars. How often should we spray?? There is no clear answer, but these chemicals are broken down in bright sunlight. Apparently there is an additive to reduce this effect. Whilst we have so many infected palms in our area, I shall try to spray every 3 weeks. Despite these preventative measures, we may still lose our palms. Should we use Pheromone Traps? The best advice seems not to use them unless your palms are already infected, otherwise they will only attract weevils from other palms.

PERSONAL SAFETY – Palms, especially the Canary palm have very dangerous spikes. As you will need to get in close, especially to get to the heart , you should particularly protect your head, face and hands. Both of the chemicals sprayed are moderately toxic. MY protection is:- a) Safety helmet with visor b) Carbon Filter gas mask to prevent chemical inhalation, rather than paper mask for dust c) Tough rubber gloves d) Waterproof anorak and trousers (see picture to the left!). I am very grateful to Ioannis Kalogerakis BSc. MSc. from Agro garden center in Missiria for the information in this article.’ Bob Wright bobandev@otenet.gr

Cleaning The Myloi Gorge. More Rubbish!

Tania Traas writes: ‘Last month I spent several hours in the Myloi Gorge (a beautiful nature site just outside Rethymnon) trying to remove all the rubbish which had piled up. For those of you who have walked there, you probably know the picnic place and the more or less renovated mill: Unfortunately those two places are (were!) covered in left behind rubbish and no one seems to clean up there. In both places there was a barrel / oil drum which one would think were garbage bins, but nobody seems to empty them.

Last year I walked the Myloi Gorge once a week with guests from The Happy Walker and more and more I felt ashamed to show them these places. So I decided to clean it myself. I could have gone to the Dimarchio, but....! In the end I took out 12 big bags (120 litres each) of rubbish and removed the barrels. I also made a few signs (in Greek) to put there, asking people not to leave their rubbish in the gorge; the gorge is popular for Greeks to have picnics at Easter and the 1st of May (certain types of tourists are also guilty!) If anyone who reads this has a suggestion to involve the Dimarchio in this, please tell the Coffee Morning Bugle!’