The Control of the Desert Locusts (Schistocerca Gregaria) in Somalia During the Upsurge Between 2019 and 2021

Abstract

The desert "empty quarter" area of Saudi Arabia, together with Oman and, Yemen, was hit by a cyclone in May 2018, that resulted in vegetation flourishing and enabled the locust population present to increase 400-fold over the following six months. Following a second cyclone in October 2018, the population continued to increase an estimated 8000-fold. Swarms of these locusts in March 2019 flew east into southern Iran and thence to India and Pakistan. A change in wind direction enabled others to fly south into Yemen, where a civil war hindered any control operations. From Yemen, swarms moved to Ethiopia and Somalia in October 2019 and later into Kenya. In contrast to most countries, nomadic pastoralists in Somalia are nearly two-thirds of the population and occupy about two-thirds of the country. The ecology of nomadic pastoralism is an adaptation to an environment in which the availability of water and grass are critical factors. The life of pastoralists differs significantly from sedentary agriculturalists and is based on natural resource management that respects the limitations imposed on their environment, the necessity for mobility. To protect the pastoral system, the Government was concerned about the applying insecticides over vast areas due to the adverse impact on bees in the environment and on livestock that grazed on the pastures. Assisted by FAO, it was decided that locusts had to be controlled by the biopesticide, based on the fungus Metarhizium acridum, which produces a toxin that kills only locusts and related grasshoppers. The biopesticide, originally called "Green Muscle" was developed in the LUBILOSA Project organised with international funding and managed by CABI (Prior et al. 1992; Lomer et al. 2001). Developments in the production of the biopesticide had reduced costs and it is more effective to apply, although it takes longer to kill locusts, it can spread through a population and be particularly effective against the hopper bands of young locusts before they fly. Since 2004, the use of Metarhizium acridum had increased in China from only 5% to over 30% as over 100,000 hectares were treated. An advantage of the biopesticide is that birds are not killed and remain effective predators of the locusts. The programme confirmed the importance of using the biopesticide to protect the environment from the use of hazardous chemical insecticides. It also indicated that there were a number of Key challenges that had to be faced, namely: Difficulty in carry out field evaluations during intensive control operations; Remoteness of control areas where caged experiments could not be conducted; Limited number of government officers capable of carrying out field / laboratory assessments; Lack of suitable laboratory facilities to carry out subsequent observations on field collected samples; Narrow daily window for control operations with Metarhizium acridum operations are required as the air temperature quickly rises beyond 30°C as early as 11.00am; Sparse vegetation cover in semiarid areas affecting barrier treatment approach using aircraft.