Pest takes a liking to lemons
A PLAGUE of insects that had not been seen before in Europe is damaging citrus fruit trees in the Vega Baja area.
Relatively little is known about the cottony citrus scale (pulvinaria polygonata), which particularly affects lemon trees, but also oranges, mandarins and clementines to a lesser extent. Since it was first detected in San Miguel de Salinas in March 2019, it has expanded across approximately 5,000 hectares into Los Montesinos, Almoradí, Bigastro, Torremendo (Orihuela) and beyond.
It is estimated to have destroyed some 100,000 tonnes of fruits by sucking the sap out of trees and leaving an excretion from the nymphs and adult males, on which black mould develops and covers leaves, branches and fruit. Affected trees are covered with a cottony white layer, which is the ovisac, a waxy secretion produced by the adult females that encloses the many eggs they lay. Although they can eat other vegetation, they are particularly fond of citruses.
Regional agriculture councillor Mireia Mollà said this illustrates why since she took office a year ago she has been calling for better checks on plant materials entering the country through ports.
These imported pests are not only an additional risk for the crops but also an additional expense which reduces the profitability of farms, she said.
Sra Mollà accused the EU of being too permissive with inspections of commercial goods, ‘which forces the use of pesticides to deal with new infestations and diseases, which has a knock-on effect on the environment and the health of people and consumers’.
She also urged the minister for agriculture, Luis Planas to intensify inspections, since he has the authority to order this.
Meanwhile the regional agriculture department has discovered that there is a natural predator which is effective against the pulvinaria and already used against the citrus mealybug (planococus citri).
However, it has not acclimatised well to the area and investment is needed for facilities to breed it and make it available, she noted.
“It would take about €3 million per year to develop a viable biological alternative against a plague started by insufficient border controls,” noted Sra Mollà.