Madagascar: locusts spread north towards main agricultural areas

The African Migratory Locust - now threatening Madagascar's staple rice crops

A massive plague of locusts is threatening Madagascar's staple rice crop. Last year farmers in the southern part of the island - the poorest part - lost up to 80 percent of their cereal crops to plagues of African Migratory Locust. This year, experts are predicting that, when the dry and cold season begins in May, vast swarms of locust will head north, towards the island's rice bowl - the fertile central plain. The rice will not be ready for harvest until July.

Adult locust swarms - made up of millions of insects on the move - devour the plants they settle on, leaving just the stalks. Local rice crops are crucial to the food security of the island's 15.5 million people, 75 percent of whom live below the poverty line. Cereals make up approximately 55 percent of the average diet and rice consumption for 1997/98 is projected to top the 1.7 million tonne mark.

Experts on the ground in southern Madagascar have reported that more than 5 million hectares are heavily infested. This is five times the area estimated to have been infested in February 1997.

Hoppers devour a maize plant in southern Madagascar where more than 5 million hectares are heavily infested

Earlier this year, FAO launched an international appeal for US$12 million to fight the plague. So far US$8 million have been pledged and control operations have begun. Five fixed-wing aircraft and a helicopter have been chartered and pesticides supplied. Part of the assistance is provided bilaterally, other donors provide such through FAO.

The Government has drafted in the army to take the lead, in collaboration with technicians from the Ministry of Agriculture's Plant Protection Service. But the terrain is rugged and there are few roads. So far, only 10 percent of the 5 million infested hectares have been sprayed. Locusts breed five times a year, and can multiply their numbers by five to ten with every new generation.

Top priority now is to spray as many hopper bands as possible. These are groups of locusts that are not yet mature enough to fly. At this point, although they may cover vast areas, they can be treated with much less insecticide than that necessary for swarming adults. Areas where large hopper bands occur are sprayed from the air in strips a kilometre apart. The pesticides are effective for three weeks, during which time the moving insects will encounter a sprayed strip of land. Smaller hopper bands are sprayed by teams on the ground with back-pack spraying units. Once the locusts are mature and take to the air, blanket spraying is the only answer.

7 April 1998

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