LOCUST PLAGUE—UVAROV 343 
obtaining the willing cooperation of all concerned. This made it 
possible, for the first time in the history of locust control, to organize 
not a dozen small national campaigns designed mainly for defense, 
but a unified campaign embracing the whole affected area and assum- 
ing the character of offensive operations. These operations are based 
on a knowledge of the seasonal movements of swarms, which has been 
accumulated in past years and which makes it possible to forecast 
the course of events with considerable accuracy. It is a matter of 
justifiable pride for the Anti-Locust Centre that in the present in- 
vasion every country has received a timely warning, and that these 
warnings have proved to be correct. 
THE INTERNATIONAL ANTI-LOCUST CAMPAIGN 
Seasonal movements of the desert locust cover an enormous region. 
Swarms produced during the summer monsoon rains in India fly 
in the autumn to southern Persia and Arabia; the latter country 
receives about the same time the swarms bred on summer rains in 
Africa. The winter and spring rains in Arabia and southern Persia 
enable these locusts to multiply and the new swarms produced in 
these countries move during the spring into Sinai, Egypt, Palestine, 
Syria, Iraq, Central Persia, Afghanistan, and India, sometimes reach- 
ing as far north as Turkey and Soviet Middle Asia, breeding wherever 
they meet rains. The Red Sea, Gulf of Aden, and even the Arabian 
Sea are liable to be crossed by swarms migrating between Africa, 
Arabia, Persia, and India. Many swarms from Arabia cross to the 
Sudan, Eritrea, and Ethiopia, where they are able to breed again on 
summer rains. In the Somalilands, Ethiopia, and East Africa, the 
seasons are somewhat different, but the principle remains the same, 
since locust swarms always evacuate a region which becomes too dry 
and migrate to a rainy one. As a result, the whole enormous region 
stretching from East Africa to India has to be regarded as a single 
interconnected migration area. Obviously, the general strategy of 
the anti-locust campaign had to be based on the knowledge where and 
when the enemy could be best attacked. An essential principle of 
this strategy was to evolve a single plan of the campaign, with a 
view to exterminating locust swarms wherever this can be done with 
the maximum effect. 
In planning the campaign, it was essential to make full use of the 
fact that in many of the affected countries there existed efficient 
local entomological organizations. Such organizations in India, 
Anglo-Egyptian Sudan, and the British East African colonies could 
be relied upon to organize locust control in their own territories, 
within the framework of the general campaign. Some of them went 
further, and generously offered their assistance to the surrounding 
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