Studies on Population Dynamics of Senegalese Grasshopper (Oedaleus senegalensis) in Kordofan of Sudan

摘要

The Senegalese grasshopper (Oedaleus senegalensis) is a serious pest affecting cereal crops and grassy pastures in western Sudan. Intensive and extensive field’s surveys were conducted over a three-year period targeting O. senegalensis to study its ratio among other grasshopper species, in addition to its density and population structure/dynamics. Observations made twice a week, between April and November for three years (2006-2008) in two sites in Kordofan. Light traps installed in three selected areas to study nocturnal activity and migration every night from April to November for two seasons (2007/2008). The density assessed by visual counts of the nymph instars in 100 m2 and adults in 1,000 m2. The obtained data were analyzed using descriptive statistics. Results revealed that the Senegalese grasshopper is dominant over other grasshopper species and that the adults and nymphal instars appeared in two morphs: green and brown, according to prevailing environmental conditions. Mean population density was 1037 adult/ha and 3464 adult/ha in Kuik and Gellabiya sites, respectively; for nymphal instars, 2145 nymph/ha and 5500 nymph/ha, in Kuik and Gellabiya sites respectively.