A locust infestation in the Horn of Africa has spread to eastern Kenya, where farmers are fearful of crop losses.Swarms have been spotted in Kenya's Isiolo county and Meru county - the latter region famous for producing the stimulant plant khat, though it is not known if the locusts are partial to those leaves.Over the last two months, the infestation has affected several states in Ethiopia and has seen farmers lose nearly 100% of their crops, according to the UN.The desert locusts have also devoured crops and pasture in Somalia, where insecurity has made it difficult to use aeroplanes for the aerial spraying of pesticides.The Food and Agricultural Organization (FAO) said a number of large immature swarms reached the arid region of north-eastern Kenya on 28 December.In Meru, a local chief, Romano Muchiri, told Kenya’s private Daily Nation newspaper that he had seen wingless locusts feeding on shrubs – this means they are recently hatched hoppers or nymphs.Isiolo County Commissioner Narman Shambi told the newspaper that the swarms had covered and area of up to 3,000 sq km (1,158 sq miles).Residents have appealed for help to save their harvests.Earlier this week, the government announced the beginning of aerial spraying of the locusts in the northern counties of Wajir and Marsabit.