Locust control programs

Research on desert and red locusts did not start until the 1920s,'1 although outbreaks were reported as early as 1916. Finding immediate and long-term solutions required proper understanding of the cycles of swarming and possible methods of control. One strategy' was to attack and destroy isolated locust populations, to stop them from breaking out of the source regions. This required timely interventions during the recession phase, before the locusts laid eggs to start the next swarming generations. Another strategy was to destroy hoppers, which required regular monitoring by mapping the breeding grounds and mobilizing logistics to attack the swarms before they became mobile.'2 However, locust control was not a one-off event, considering that invasions from the outbreak areas were an ongoing—and sometimes unpredictable—occurrence.” We now consider regional and international efforts to halt the swarms before they reached further agricultural regions in East Africa.

Regional control

The control methods were either ‘reactive’ or ‘preventive’—the former being an emergency response to swarms that suddenly invaded a region.'4 The reactive method has been compared to attempting to stop hurricanes; one could only minimize the damage, but it would be impossible to stop hurricanes.” Even if locusts could not be stopped by attacking them, the damage they caused might be reduced. The most preferred method is preventive—that is, to stop the swarms in their breeding and hopper stages, since after they have taken flight, control becomes much more costly.'6 After the 1940s, on the recommendations of Sir Boris Uvarov, the scientific advisor to the locust control in Britain, the preventive strategy was used to attack swarms in the outbreak areas, before they had an opportunity to invade other countries." Preventive methods required various monitoring systems (see later section). The challenge was the scale of control, across many countries simultaneously, and during successive generations of locust populations.'8

Due to their fast-moving habits, one might imagine that locusts are unstoppable. However, there are weak points in their population cycles, at which the swarms might be attacked and destroyed, particularly during solitary and hopper phases when they are the most vulnerable.'9 The methods included physical attacks during the hopper stage, such as digging trenches in their paths, using tree branches to kill as many hoppers as possible, and use of fire and poisoned bait. For mature locust swarms, pesticides were applied (see later section). However, as mentioned before, such surveillance and control methods provided emergency responses as opposed to longterm solutions. Consequently, a policy of a limited number of campaigns was proposed, but this was criticized by both the administration and the affected communities. Halting the locust invasions usually involved political dimensions and decisions. For the African farmers, the idea that scientists were determined to estimate the losses, but did not do much to stop the swarms, caused much apprehension. Their preferred solution was to take immediate control of the swarms, regardless of the consequences.80 If not stopped before they reached their destinations, severe damage to agricultural production would be inevitable.81 During the Second World War, the authorities’ methods of controlling locust plagues were not effective due to a lack of capacity to coordinate the control of the pests over large areas. This meant that each event became a crisis until later in the 1950s, when institutional capacities had improved.82 Owing to the multiple invasion threats, locust control required vigilance and continuous campaigns, stretching planned preventive surveys into operations against new threats, which inevitably required extensive and well-funded organization.85 Control methods needed to take into consideration the sporadic outbreaks that were difficult to predict. This required the coordination of locust campaigns over several outbreak regions simultaneously.84 If not stopped, these swarms would pose a direct threat to agricultural regions in East Africa.8’ In the Somali Peninsula, in the 1950s, a major initiative was launched in the fight against this huge desert locust plague—squads were recruited from local communities (comprising a total of 4,367 men) and a strong team of 100 officers with supplies ferried to the affected areas by some 250 vehicles. The campaign destroyed more than 1 million hopper bands. However, setbacks were suffered due to inaccessible countryside, thus giving the locusts the opportunity to escape and continue to form large swarms.86 When successful, locust control was attributable to various forms of international collaborations.8'

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