It is known as greening and is a lethal bacterium for citrus. It is transmitted by an insect whose presence has already been detected in Spain, in particular in Galicia, but also in Portugal. There is no solution or treatment once the tree has been infected; the only way out is its destruction. And prevention is the only way to fight against it.
Taking into account these facts, the interprofessional lemon organization Ailimpo, in partnership with Koppert and Cajamar, recently organised a technical day in Murcia regarding biological control in citrus and strategies for the prevention and control of Greening disease or HLB (Huanglongbing). It was given by Leandro Peña, one of the world's experts in this bacterium, who is currently working in Brazil; a country that has been seriously affected by the pest. More than a hundred producers and entrepreneurs attended the talk.
In Spain, a lemon production of around 1 million tonnes is at stake; 600,000 in the Region of Murcia alone. The country has around 39,000 hectares; 22,000 in Murcia, which means that of the 9 million lemon trees in Spain, Murcia has 6 million.
The Valencian researcher commented that, in Florida, this disease is killing the trees, and within three to four years citrus growing could come to an end in this US state, one of the world's most important producers. "It is a pest that kills; there is no cure and there is no resistant variety."
In Brazil, which is where the expert works, they are, he said, "surviving," as 40 million trees have been uprooted so far. "Spain could never resist an attack like this. Uprooting millions of trees is not an option and the best strategy we have is prevention," he pointed out.
Having systems and regulations in place to prevent its spread is deemed the only way to ensure that greening does not affect the trees.
Peña pointed out that if the insect moved from Portugal or Galicia, which is very possible, because "nothing is being done to prevent it, we will have it here in a few years." With the insect, any movement of infected plant material could cause the pest to spread like wildfire. "The threat for Murcia, Andalusia and Valencia is currently in Portugal and Galicia," he insisted.
The expert considers it essential for the regional, national and even European administrations to collaborate and prevent the disease's spread.
"With proper laws and plans, it could be controlled, and it would also be necessary to become more alert to prevent the traffic of plants from other countries, which is prohibited, but is done all the same," he stated, stressing that this bacterium also affects shrubs and ornamental plants, "and these are much less regulated from a phytosanitary point of view."
The researcher has made an appeal for citizen collaboration in general, to think long before bringing plants from other countries, as great and irreversible damage could be caused to this important economic sector.