The 'black fog’ Africa dreads

Press, 16 June 1978, Page 6

The 'black fog’ Africa dreads

By BOYCE RENSBERGER, ; science writer for the - “New York Times” ’ (through NZPA) New York For years they creep about innocuously on scrubby ridesert vegetation, munching -Itorpidly in the African or I (Arabian sun. Rather like 5 grasshoppers during these ■(times, they live almost soli- • tary lives’ of little conses’quence to human beings. >: Then, suddenly, something f ’comes over the sleepy grasshoppers. Their numbers i’explode into marauding > hordes of desert locusts, II swarming by the hundreds of ■■millions out of the arid >! zones, denuding forests and ,(fields and wreaking a destruction that, at least since iißiblical times, has been recognised as among the worst I of God’s punishments. ;! For weeks or months or, in some cases, for years, the

pestilence may continue, 'shifting with the winds. (Eventually the plague sub-; (Sides and the locusts return Ito their quiet ways and’ t!sparse numbers. y| The quiet phase of the’ g * desert locusts’ two ways of) r lift appears to be ending' e inow after eight years in East’ e i Africa and the Arabian; J Peninsula. Swarms of locusts, 1 .’some blanketing areas of up) (to 10,000 ha (about 25,000; J acres), have been spotted in* ’(recent weeks in Ethiopia,; s l Somalia, and Djibouti. J; Pesticide-spraying planes ’’have been sent aloft to 1 f'attack the swamis, but, y; veteran locust-control ex-’ jperts say surveillance of out-’ .’breaks is so poor that there j is grave danger to crops and* “'grazing lands. t t Until the Ethiopian: wars in Ogaden and Eritrea ■ ’disrupted it, a net-’ e)work of ground-based locust!

. observation stations had been I < .’monitoring the insects for’: •Isigns of a transformation.; i'With famine already touch-; I ling some parts of Ethiopia |i ’because of drought, a locustp ■plague would almost in-ji fjstantly multiply the scale of;; ( human suffering and death. ) i| If small swarms area Hallowed to multiply un-ll checked, they can become; i)enormous infestations, cap-p liable of sweeping across the’s i agricultural areas of Kenya,’! .’Tanzania, and Uganda to the’i ■‘south or, depending on the;: II winds, the Sudan to the west; I i* or Egypt to the north. |i Swarms’ now developing on’t ■’the Arabian Peninsula could ; ■’move westward into Africa;f or eastward to Iran, Paki-;f ’stan, and India. Fighting at locust outbreak is like fight- t Sing a forest fire — once itri .’gets out of control almost’ 1 ’nothing can stop it. ’ Like billowing storm;!

Iclouds, locust swarms can 'suddenly loom on the hori;zon. Moving anywhere from i 16km to 160 km a day, the ’crackling sound of beating wings becomes a roar as the ’ravenous insects approach in a cohesive mass that flows like a black fog. Such masses ’of locusts commonly blanket )25,000ha (62,500 acres). * In 250 ha of a well-packed ’swarm, according to some 'sources, there can be 100 million locusts, each weigh’ing .05g and trying to consume twice its weight in ’food every day. Swarms | move in a kind of rolling action, with the lead locusts settling on vegetation to feed and rest, while others, feeding behind under the cloud, take off and race to the edge of the swarm to find new vegetation. Within a swarm, locusts fly in all directions but, gs a

a I mass, the swarm tends to -move with the prevailing a’winds. If the winds carry e;the swarm to sea or into g; desert areas, the plague may e die out. However, since lonlcusts can fly a documented s; 17 hours without stopping, s I they are often able to pass t over large zones of inhospitable terrain to reach i (greener pastures. s Even in favourable enviJ ronments, however, there is -1 evidence that the swarming - phase of the desert locust’s i life comes to an end after s ’ what may be a pre- -' determined time. Though the s human suffering and recovrery effort may continue for , ’ months or years, the locusts ’ I return fairly quickly to their o' solitary lives to wait out ano other interval before conditions, whatever they may be, 5 favour a new swarming i phase.