ENVIRONMENT-EUROPE: Invaders Strike Again

By Mario de Queiroz Reprint | | Print |

Mario de Queiroz

LISBON, Dec 10 2004 (IPS) - It had been half a century since they last invaded Europe. But they have once again crossed the Strait of Gibraltar in search of food in the southern part of the Iberian peninsula.

Although the invaders are just a few centimetres long, they come in swarms that devour everything in their path. In 1954, millions of desert locusts (Schistocerca gregaria) from Africa reached as far north as the British Isles, and this month they made it to Spain’s Canary Islands and the southern Portuguese region of Algarve, which has one of the mildest winter climates in Europe.

But United Nations Food and Agriculture Organisation (FAO) experts believe they will not make it any farther than southern Portugal this time around.

The locusts have already begun to die in the Canary Islands, as well as in the Algarve, where temperatures at this time of year range between 16 and 22 degrees Celsius.

That is very cold for the locusts, which normally go no farther north than Algeria, Libya, Morocco and Tunisia, where they remain inactive throughout the winter.

Nevertheless, farmers in Spain and Portugal are still worried, because despite the huge amounts of insecticides sprayed in several West African nations, the plague, the worst in 15 years, has destroyed millions of hectares of crops in that region.

Every year, a reduced number of locusts survive the winter in Africa’s Sahel region – the transition zone between the Sahara Desert and the more fertile lands that lie to the south – and the North African countries on the southern shores of the Mediterranean.

To ensure the survival of the species in hostile weather conditions, the insects lay between 100 and 150 eggs each. But few actually hatch and make it to adulthood, since they need moisture, which is usually in short supply in that region.

However, weather conditions have become more and more unpredictable, due to climate change caused by carbon dioxide emissions, which trap heat in the earth’s atmosphere, leading to the so-called greenhouse effect.

Thus, on Oct. 21-22, 2003, torrential rains in the southern Sahara created ideal breeding conditions for the locusts, explained an article in the Portuguese weekly Visao.

According to Keith Cressman, head of FAO’s desert locust prevention efforts, 200 millimetres of water fell in late October, 2003 in areas that receive an average of one millimetre of water a year, providing favourable conditions for the eggs to hatch.

The desert locust can reach 15 centimetres in length, consumes roughly its own weight (around two grams) in fresh food per day, and has a life-span of three to five months. But although it is normally solitary, when the population increases dramatically, it turns from brown to pink and alters its behaviour, moving in large groups, and devouring vegetables, grains and even the clothing and tents of desert nomads.

After the eggs hatch in North Africa, the immature insects fly south, and in some cases, depending on the winds, they reach Egypt to the east and the Canary Islands (off the northwest coast of Africa) to the west.

By March 2004, locust swarms had grown and spread in Africa to the extent that the countries affected launched a plea for international aid, and tons of insecticides were sprayed in the most critical areas.

In the springtime, the worst locust plagues were seen in Algeria, Libya, Niger, Morocco, Mauritania and Sudan. A different species of locust was also wreaking havoc in Saudi Arabia.

>From June through August, the swarms began to fly southwards again, pushed by the strong winds from the north that are frequent during that season of the year. In July, locusts flew across several hundred kilometres of Atlantic Ocean to reach Cape Verde, off the coast of West Africa.

Despite the heavy use of insecticides, the swarms continued to grow, and in September, the winds from the south drove them northwards from Mali, Mauritania and Senegal.

Farmers in North Africa and southern Europe are now praying for cold, dry weather, to halt the insect’s breeding cycle.

Locust plagues and the devastation they wreak on crops have terrified humanity since the dawn of written history.

The Bible itself, in Exodus 10:15, says "For they covered the face of the whole earth, so that the land was darkened; and they did eat every herb of the land, and all the fruit of the trees which the hail had left: and there remained not any green thing, either tree or herb of the field, through all the land of Egypt."