Geospatial Analysis For Determination Of Preferential Soil Conditions For The Desert Locust Oviposition

Abstract

Understanding the thresholds of influencing parameters that favor the habitability of dangerous pests like desert locusts (Schistocerca gregaria) can aid in early detection and eradication using control operations. The life cycle of the desert locust and its behavioral changes are associated with the weather patterns and the region’s ecosystem settings. This study attempts to retrieve the preferential soil conditions like texture and moisture at the surface and subsurface levels for egg-laying by desert locusts. Towards this, Locust Hub, a comprehensive database of desert locusts maintained and disseminated by the Food and Agriculture Organisation under the Locust Watch program, was used to identify breeding site locations for 2017-2021. In this research, we extracted sand-silt-clay percentage at these breeding sites using SoilGrids ver. 2.0 from the World Soil Information Service database facilitated by International Soil Reference and Information Centre. Similarly, soil moisture conditions extracted from Level-4 data products of the Soil Moisture Active Passive mission for all these breeding sites aided in essaying the optimal soil conditions for the desert locust’s oviposition. This study’s results confirm the sand percentage in a broad range of 55-70% (for 90% of samples), followed by a narrow range of silt and clay with 19-24% and ~14-20%, respectively. Our study reveals that female desert locusts prefer sandy loam-textured soils for oviposition. The preferred range of soil moisture at the surface and subsurface resulted in 5-10% and 10-20%, respectively. These results confirm that dampness is required at the surface soil for initiating the oviposition by female desert locusts. Results from this research can aid in the early identification of breeding grounds during desert locusts’ invasion period.