• Full Screen
  • Wide Screen
  • Narrow Screen
  • Increase font size
  • Default font size
  • Decrease font size
Print PDF

Part one
Time is running you read this, thousands of ‘invisible’ little bugs are slowly but surely eating their way through the majestic palm trees of the Southern Hemisphere – Thousands have already been destroyed globally, and experts agree that “within the next two to three years, hundreds, if not thousands” of trees in Southern Europe will almost certainly suffer the same fate.

Portugal is one of the latest areas to be hit by this relentless beetle, which can live its entire life-cycle hidden within its host tree, and entomologists, researchers and a few nurseries know they have solutions... the problem – almost larger than the threat itself - is getting Governments/ local authorities to act effectively, and in time help bring an end to the devastating toll of dead trees.

Environmentalist Antonio Lambe, however, has researched the issue independently. Known for his interest in the field, he was called in by Manuel Rodrigues, the director of Parks and Landscaping at Silves Câmara (Portugal) after a number of the borough’s palms were found to be infested – and he’s compiled a pretty shocking list of host species: It is certainly not just the Phoenix canariensis that is at risk, although it is the prime victim. There are more than 32 other hosts, including the palms popular in garden landscaping, Washingtonia robusta, Washingtonia filifera and the smaller indigenous wild palms, Chamaerops humilis. “I’m not trying to sell anything. I’m simply trying to promote awareness and action,” Lambe explained. “Red Palm Weevil reached Europe 15 years ago – yet it took Brussels until May last year (2007) to finally adopt ‘emergency measures’ to prevent its introduction into the Community. By that time, generations of the bug had been active in every major EU Mediterranean country for years!”

Lambe has begun to lobby authorities in Portugal and in Brussels for support – principally for research into treatment/ prevention and cost subsidies. Currently it can cost up to €450 annually to treat diseased trees effectively – and that is a price way beyond many people’s budgets. Mauro Aguiar explained that local 4- and 5-star holiday complexes, that are adorned with Palms, would be perfectly able to afford the costly treatments – particularly as the price of replacing trees would work out far higher.

But local councils/ private homeowners are not usually in this position – and that, of course, is where another problem lies: unless everyone acts to protect their trees, the bugs will never be fully eradicated. At Flor do Sol’s nurseries, near Portimão, Aguiar suggests people able to treat their trees should do so irrespective of any signs of infestation - year in, year out. But Antonio Lambe would disagree. His research has led him to a number of conclusions and he’s putting these all together in a booklet to distribute to garden centres to help combat Rhynchophorus ferrugineus and save the Algarve’s legendary tropical landscape.

As Mauro Aguiar explained, researchers are working round the clock to come up with “the bomb to end all bombs” for this pest – as current chemical treatments only work on each infestation. They don’t prevent infestations in the future. “The solution, in the end, will have to be biological,” he explained. “And, I can assure you – companies are racing against each other to be the ones to get it right.”

Part two

The Red Palm Weevil (Latin name: Rhynchophorus ferrugineus) originated in South-east Asia and Melanesia more than a century ago. It first arrived in Southern Europe in the 1980s – discovering the delights of two ubiquitous date palm species, Phoenix canariensis and Phoenix dactylifera, which it seems to prefer over all the other potential host palms. That’s the first bit of ‘good news’ as this lets people focus on prevention programmes for these palms before worrying about any others – but here things get difficult again: Phoenix canariensis palms are everywhere – and one of the hardest things about controlling this bug is that it can remain ‘out of sight’, within its host tree, for its entire life-cycle: right from the moment when the female weevil lays her 300-odd eggs, to the time it emerges from its pupa as a full-grown reddish- brown adult beetle equipped with wings, and capable of flying considerable distances. The weevils are content to spend their whole lives in the same tree – but if the tree dies, they rapidly move on to a new host.

Another daunting problem is that there’s a relatively long period between infestation and any indication that something is wrong with the tree – but correspondingly there’s a much shorter period between the first warning signs and the point where the tree becomes unrecoverable. “It is all about control,” palm specialist and agronomist Mauro Aguiar explains from one of the Algarve’s premier palm tree nurseries, Flor do Sol, near Portimão. “If owners watch out for warning signs, there is nearly always the chance of full recovery. But we have to get to the tree in time.” reatment/ prevention This has to be two- if not three-pronged and can also be used as a form of prevention year in, year out (a bit like dog owners who treat their dogs regularly for the possibility of contracting diseases like heartworm): Two types of insecticide need to be applied in different ways -

• Contact insecticides are sprayed on the leaves (to kill  insects, eggs and pupae that may be on the surface) and

• systemic insecticides, which the tree will absorb and  incorporate in its tissues, are injected into the trunk to tackle concealed larvae. Experts agree that each affected tree should receive at least two treatments – and warn that treatments are only effective for  a certain period of time. A tree that has been infested, and then cured, can easily become infested again. “It is important to transmit the idea that this pest can be  controlled, but in order to do so every owner has to adopt the same strategy,” research scientist Michel Ferry, working in  Spain, explained. “It simply doesn’t work if one palm owner is     looking after their trees, but his neighbour isn’t.” (Remember        that Spain has lost 10,000 palms to Red Palm Weevil just this       year in the province of Andalusia alone. That’s just a couple of        hours’ drive down the motorway.)         There are also two other, much easier measures to safeguard        trees – without using chemicals:

• No 1 is the weevil trap: essentially a large bucket with side openings and a top cover from which scent lures are hung – the idea being that the bugs are attracted by the scent of the trap (more than the scent of the nearby palm tree), and then fall into the watery rotten fruit mixture at the bottom of the bucket and drown.

• No 2 is a ‘relaxed approach’ to pruning: bearing in mind that these bugs are drawn by smell, pruning acts like the red rag to the proverbial bull. Environmentalist Antonio Lambe – a keen supporter of non-chemical methods of prevention – recommends that people should let lower fronds dry before removal, or cut them no closer than a metre from the trunk. “Insecticides are not the ultimate solution,” he warns. They are also expensive. Treating diseased trees can cost anything between € 350 – 450 per tree.

Lambe is currently working on an information booklet which he hopes to make available to garden centres and nurseries very soon. He has also been lobbying for Government/ EU support in the efforts to combat the Red Palm Weevil, maintaining that subsidies must be forthcoming to fund treatment/ prevention and research. Sadly, the response so far has all been “too little too late”. Nevertheless, Lambe is urging the Community to set up a website so that information and advice can be made available to people in all major languages. “The danger presented by the weevil will only be overcome by concerted efforts in all areas where it is found. It is still new in Portugal and we have an opportunity to learn from the mistakes of others. We must not waste it,” he concludes.