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The Palm Beetle - Update.
In the last four years, I’ve written four times about the march of the palm beetle and still it carries on marching! So, here is the latest update on the situation within Spain.
In the period from 1996 – 2009, 49,800 palms have been officially destroyed as a direct result of the picudo rojo. The cost of this is estimated to be in the region of 100 million euro. The cost to private gardeners has not been included within these figures and is a large unknown.
El Palmeral de Elche (the palm park in Elche designated by UNESCO as a World Heritage Centre) has been leading a lot of the research work and they have recently announced a high degree of success in killing the larvae and the beetles through the use of an insecticide known as Actara (active ingredient is Tiametoxam) produced by Syngenta.es It is injected into the base of the trunk of the palms (efficacious in those unaffected and those with a low degree of infestation) and it is absorbed through the plant. Thirteen days after the application it starts killing the larvae –some 31% will die – increasing to 100% with subsequent applications. The injections need to be carried out twice yearly as a preventative. Now for the bad news: for a large palm, each injection costs €150. It has been said that if all our palms were thus treated, the palm beetle would disappear from our shores – but at that cost I find it hard to believe that there will be a huge demand from private gardeners and municipal authorities.
There are other chemicals that seem to have some degree of success but they are still costly. Confidor is popularly used – cheaper alternatives are Ganador or Midas. A cheaper alternative to Durbans, another possibility, is Chas. If your palm seems unaffected, spray monthly with one of these; spray fortnightly if the tree is looking ill. Applications are not necessary during the colder months. They’ll need to be mixed with Ditene to improve its absorption and with Nitromax to fortify the palm. This mix has to be applied over the entire head of the palm, especially into the heart. There are no guarantees and if your palm is clearly affected, then there’s little chance of saving it. I’ve seen examples of palms that have been saved only to become re-infected because preventative measures were not continued.
Wear protective clothing – especially a full-face mask – we are talking very deadly stuff. All of these chemicals are also very toxic to bees.
Some success has been had with pheromone traps and nematodes – both have, at least, meant that less insecticide can be used – but where there is a density of palms insecticide is being dispersed by small planes.
Personally, we have numerous clients at the garden centre who have been treating their palms for a couple of years, or so, with Neem oil with success. The cost is relatively low, the only inconvenience being that the treatments are weekly during the warmer months. But it is organic and does no harm to our beneficial insects – a huge consideration. Consider that, on one hand, we are bemoaning the loss of our bees, (not just a whimsy, even commercial growers are noticing severely reduced harvests) and, on the other, we are heavily polluting to try to solve an introduced problem! Palms are still being imported from Egypt, from whence the entire infestation began.
The financial cost (of course!) features largely. Cash-strapped Town Halls, large and small, are insisting that the Juntas should shoulder, at least, 50% of the cost, not only of treatments but also disposing of dead/infested palms. With cutbacks of all sorts, the argument seems likely to rumble on whilst the beetle marches on to new pastures. Whilst it seems to prefer the phoenix family of palms, shortages of its favourite food are leading to the beetle scavenging far and wide. The Town Hall in Malaga, for instance, has said that a large kentia palm in the Parque de Malaga has been killed by the beetle and there are numerous claims from official sources of attacks to all sorts of palms, trees and, even, sugar cane. The Spanish Mediterranean climate suits them well, with its relatively short and mild winters, enabling the beetle to reproduce throughout the year. Most of our cities are botanically rich. As the picudo rojo amplifies its food sources, the damage to our plants and the cost of control could skyrocket.
Remember that, within this country, the palm weevil only has one predator and that is man. We introduced it into Spain and we are the only ones that can stop its progress. Let’s do it responsibly.
In next week’s thrilling instalment, I’ll tell you about a new arrival that is also hungry for our palms!