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Attack of the Red Palm Weevil Beetle
Arriving in Andalucia, southern Spain, in 1994, the red palm weevil (Rhynchophorus ferrugineus) is causing the destruction of thousands of affected palm trees throughout Spain.
So far, no effective remedy has been found except chopping the infected trees down and burning them.
Insecticides work against the red palm weevils (Sp. picudo rojo) when tested under laboratory conditions, but out in the field they are failing miserably. Various methods have been used to spray, inject or otherwise treat trees with insecticide, but the life cycle of the red palm weevil gets slowed but not halted.
Historically, these insects belong to Southern Asia where it causes severe problems for coconut producers, but they have been advancing to the Western hemisphere since the mid 1980s, reaching Saudi Arabia in 1985, then spreading throughout the entire UAE and to Oman, reaching Iran in 1990. It was first discovered in Egypt in 1992 where it spread through the exportation of infected palms to Spain in 1994.
By 1999 it had been found in Israel, Jordan and Palestine.
Trees affected worldwide by R. ferrugineus
- Areca catechu
- Arenga saccharifera
- Arenga pinnata
- Borassus fl abellifer
- Borassus sp.
- Calamus merrillii
- Caryota cumingii
- Caryota maxima
- Cocos nucifera
- Corypha utan (= C. gebanga, C. elata)
- Corypha umbraculifer
- Elaeis guineensis
- Livistona decipiens
- Livistonac saribus (= Livistona cochinchinensis)
- Livistonac subglobosa
- Metroxylon sagu
- Oneosperma horrida
- Oneosperma tigillarium
- Phoenix canariensis
- Phoenix dactylifera
- Phoenix sylvestris
- Sabal umbraculifera
- Trachycarpus fortunei and Washingtonia sp., plus
- sugar cane, Saccharum offi cinarum and
- century plant, Agave americana.
Lifecycle of the red Palm Weevil
The female weevil lays about 300 eggs inside crack and fissures in the palm tree.
In 2 - 5 days these eggs hatch into larvae that look like maggots.
They bury themselves deep inside the tree eating fibrous tissue along the way.
One to three months later the larvae mature into pupae, each coccooned in a basket of fibrous strands.
They remain in the state until they emerge as fully fledged adult weevils 2 to 3 weeks later.
Last year my Phoenix palm showed visible evidence of the weevil, i.i. badly chewed fronds and a few of the grubs; subsequently, it was condemned by two experts. I was quoted €300 for its removal. However, prior to going ahead I sought the advice of my local garden centre who prescribed a certain course of treatment, although without any guarantee. The treatment required to have an insecticide called IMAXI (3 capfuls in 9 litres of water)sprayed into the crown of the palm every 20 days for 4 months and monthly thereafter. Additionally, a further 9 litres poured around the base of the palm. In my case, it has been 9 months since there was any evidence of the weevil and I am just about to prune the last two chewed fronds. All of the new growth is green and strong and the tree produces copious amounts of healthy flowers. It may not work for everyone, but it's certainly worth a try - it certainly worked for me!
Ken Turner, Urb La Marina
Quoted from Round Town News Letters Page 11 - 17 February, 2011.
Identifying Infected Trees
Because the larvae are buried deep inside the tree, it is impossible to tell if a tree is infected or not until the first signs of death appear, which may only be the yellowing of one or two leaves. By that time it is too late and the tree is dying, because it has been eaten from the inside out.
The only option left is to cut the tree down to the ground, and burn it immediately.
The trouble with burning is that it is a slow process, and many weevils escape to infect another tree.
It has been suggested that cutting then burying the tree remains in the ground may be more effective, as the insects cannot make their way up through the soil to escape.
There have been attempts to control this red palm weevil by chemical means, and while this seems to work under laboratory conditions, it is a procedure that is failing miserably out in the open. Various insecticidal sprays have been used.
Israel imposed strict chemical measures to be undertaken (and the immediate burning of any infected trees) when their first outbreak appeared, and it seems to have had no effect on the rising numbers of infected trees.
Spain in 1996 banned the importation of trees from affected areas, but 4 years later relaxed this ruling because the rate of infections was continuing to rise, mainly because there was no universal control placed on all European Community member states, so there was nothing to stop people importing them from other European countries.
The importation/exportation of mature palm trees is big business. There is a lot of money to be made, or lost if this insect destroys all the palm trees.
Out of Control
No-one has yet found out how to stop this weevil spreading once the first outbreak has been reported in any country.
Just this month it has been reported that the red palm weevil has now spread to Elche, Alicante, where their palm grove was declared a UNESCO World Heritage Site in the year 2000.
Elche is the main palm growing centre in Valencia. It has the largest palm grove in Europe if not the world! I was there myself a few months ago, and it was a pleasure to drive along the wide palm-lined route from Alicante city. I am told these palms have all had to be removed.
This site here about the City of Elche even describes in its first paragraph how you know you are going into Elche because of the palm tree-lined highways!
They will need to update their website :(
The main type of palm tree affected in Spain has been the Canary Island Date Palm, phoenix canariensis
- LACK OF ACTION SEES RED PALM WEEVIL MOVE IN | Costa Blanca | Leader Newspaper - News, Sport, Adverti
Michel Ferry, the Director of the Estacin Phoenix in Elche has warned that the famous Elche palms, protected by Unesco as Heritage of Mankind, are also at risk but local authorities say they hope a fall in temperatures will stop the expansion of the
- Fears for Famous Palms in Elche
There are fears for the famous palms in Elche The red palm weevil is continuing its advance across the country and is now showing its effects in Alicante province.
- The Red Palm Weevil in the Mediterranean Area
The red palm weevil, Rhynchophorus ferrugineus Olivier, has become the most important pest of the date palm in the world (Gomez & Ferry 1998).