Concerns have been raised after the detection of fire blight in medlar plantations at the Spanish town of Callosa d'en Sarrià. Local growers and the 19 town councils integrated in the designation of origin are currently on tenterhooks.
The illness, caused by bacteria, results in severe damage to the trees affected, making them unproductive. The only solution to prevent the disease from spreading is to destroy and replace the trees with other varieties that may be resistant.
Medlar trees are one of the most sensitive to fire blight, just like apple trees, pear trees and quince trees; nevertheless, some varieties are more sensitive than others. In the case of Callosa's, the most popular varieties, Agerie and Algar, appear to be among the most vulnerable.
Fire blight spreads by air and dust. Unlike other diseases affecting fruit trees, no insects act as carriers for the bacteria, and thus prevention or handling strategies designed for pest control cannot be used. It also does not spread through pruning tools or grafting, so no precautions can be taken with these either.