Infected citrus trees imported from Sicily enter Maltese market

Members of the public who purchased citrus trees in the past six months are to contact the plant health directorate

Persons who purchased a citrus tree in the past six months are to notify the Plant Health Directorate following the importation of infected trees from Sicily.

The Plant Health Directorate said that it had found a number of citrus trees infected with the Citrus Tristeza Virus (CTV).

“The infected trees, originating from Sicily, were discovered in various garden centres following sampling and testing,” the directorate said.

The virus cannot be controlled by any pesticide, and the only control mechanism is that of uprooting and burning infected trees and applying pesticides for the vectors.

“Since the symptoms are not always visible in view of latent infections, the public is requested to notify the Directorate of any purchases of citrus trees which occurred in the last six months. Trees originating from the same consignments in which infected trees were detected will be tested for the virus,” the directorate warned.

CTV is the most destructive citrus disease worldwide. Caused by a Closterovirus, it is mainly transmitted by grafting of infected material and aphid vectors. The symptoms are not always visible and may remain unnoticed for a number of years without affecting fruit setting and production.

The most recent outbreak dates back to 2012 when an area in San Blas and Daħlet Qorrot Valleys in Gozo was demarcated. During the emergency action, citrus trees of various species were felled from the contingency area and the pest was completely eradicated. In 2013, the virus was detected again in trees brought from abroad in a local nursery.

The directorate has already destroyed infected consignments. But, in order to ensure the eradication of this pest, the general public is being asked to notify the directorate of any purchase of citrus trees which occurred in the last six months.

Monitoring surveys for both the CTV and its vector have been conducted in different citrus orchards throughout Malta and Gozo since 1999, with around 800 samples collected each year. In 2004, Malta was declared as a protected zone for this disease. As a result, movement of susceptible plants is subject to monitoring, and citrus fruits introduced into Malta have to be free from any foliage and peduncles, which reduces the risk of transporting the disease and its vectors.

Any citrus trees for planting have to originate from authorised nurseries and be certified as free from the virus and vectors.

The Plant Health Directorate can be contacted on 22926535 or freephone 80072310, or at [email protected]

More in Nature