By Annette Chrysostomou
Palm trees in Cyprus are dying at an alarming rate due to a persistent pest.
Tens of thousands of palms in Cyprus have now been killed by a prolific beetle, the red palm weevil, Marios Vassiliou, course leader at the agriculture school at UCLan Cyprus IPS, told the Sunday Mail.
In the past two to three years, he added, there have been fewer incidents, simply because the insect is running out of its favourite food. The weevil prefers to feed on two types of date palms, phoenix canariensis and phoenix dactylifera, both of which are common in Cyprus.
An added danger, Vassiliou pointed out, is that when the insects have finished eating these, they will feed on the rest of the palms in Cyprus, such as the Washingtonia, planted in 1922 and which gave Larnaca’s central coastal area the name “Phinikoudes”.
But the Phinikoudes area is not the only place to worry about.
Palm trees are important in Cyprus, both for locals and tourists.
Not a native species, they have acclimatised well over many years. In urban areas, they are planted to adorn public and private buildings and some palms have been around for a long time.
“Palm trees aged over 100 years old, which adorn old buildings, are of particular cultural, historical and aesthetic value,” said a recent ministry of agriculture report. “Therefore, the protection of such palm trees but also, more generally, all palm trees found in gardens, parks, urban green areas, pavements etc. is important for maintaining the Mediterranean identity of the landscape of the island.”
Being expensive, they are also associated with wealth and are planted in gardens as a status symbol.
Outside urban areas, they are not of much agricultural commercial importance, but are often found in the grounds of hotels. Guests from colder climates associate them with exotic and tropical places in the sun and identity them with a typical Mediterranean landscape.
Thus their continuous destruction by the red palm weevil is a source of concern to many on the island. This small beetle has been around for only nine years, but has already killed many different kinds of palm trees in Cyprus.
The transport of trees across countries is the cause of the rapid spread of the red weevil palm pest all over the Mediterranean.
In Cyprus, the first infested four infested palm trees were found in a hotel in Limassol in 2006. By 2010, the insects had spread to all areas in Cyprus.
This didn’t have to happen, Vassiliou said.
“There was a delay in the state taking action. They could have controlled it when it was just in one area.” Also, he believes that the municipalities started spraying too late. At least part of the reason that the authorities are reluctant to treat the plants is the prohibiting cost. Vassiliou explained that the cost for treating one plant is €150 to €450 each year.
Red palm weevils have strong wings and are capable of undertaking flights of several kilometres within a short period of time.
Adult females lay about 300 eggs at the base of young leaves or in wounds to the leaves and trunks; the grubs feed on the soft fibres inside the tree and terminal bud tissues.
The larvae cause the most damage. They feed on the tissue until the tree eventually dies. Once a weevil has found a hole in the tree, it disappears from sight and every part of its reproduction continues to be inside the tree. At this stage, when treatment is still relatively easy, the insect is hardly visible. One way to detect a problem is to put your ear on the trunk and listen to the crunching noise of the feeding larvae. At a later stage, when visible symptoms such as holes in the trunk and crown of the tree, oozing brown liquid from trunk, and withered crown become apparent, it is often too late to stop a palm from dying.
Hundreds of insects can be in one tree at different stages of development, and they also multiply quickly. Within one year, a single adult female red palm weevil will lay over 1000 eggs, with their offspring laying another 200 eggs every ten weeks.
The good news is that there is now a comprehensive EU action plan in place to combat the pest. It includes monitoring the populations of the insect, using traps, inspecting nurseries, spraying vulnerable palm trees, cutting and destroying infected palm trees and informing the public.
A new method to combat the weevils is the use of nematode worms. This is a biological controlled measure to eradicate the pests. Worms are placed in affected palm trees and act in a parasitic way, causing the weevils’ death and dying with them when they consequently lose their food source.
This is also employed by the Cypriot government in addition to chemicals. It works with some success in winter, but with temperatures of 35C the worms die.
This means that during the summer months, the application of synthetic chemicals is recommended.
In an attempt to contain the further spread of the weevil, palms need a plant passport before they can be moved and they must have grown in a protected and inspected site. The government issues such passports and also cooperates with municipalities in order to educate the public.
A particular problem in Cyprus is the creation of demarcated areas. Infested zones should be surrounded by a 10 km buffer zone so outbreaks of pests can be controlled. In Cyprus, where the plants are ubiquitous both in urban and rural areas, this is a near impossibility now that the weevils have already spread across the country.
What can and should the owners of palm trees do?
When the insects lay their eggs in holes they often take advantage of the cracks or wounds in a recently cut palm.
Thus, a preventive measure is to seek advice from the municipality or the department of agriculture on how to correctly prune a tree. These authorities will also advise on other appropriate measures both for prevention and detection of the pest as well as its management.
Success is hampered by the secretive biological cycle within the plant, but also the difficulty in organising and involving all owners of palm trees in this effort. The monitoring, treatment and destruction of the plants is also expensive.
Your best bet may be your listening skills. Put your ear on the trunk and listen for that crunching noise, and for further information contact the web site of the agricultural ministry www.moa.gov.cy/de