Enhancing attraction and aggregation of desert locusts for efficient harvesting: Push–pull approach

Desert locusts (Schistocerca gregaria) pose a significant threat to food security. However, they also serve as a nutrient-rich delicacy in many African and Arabic communities where they are traditionally harvested for food and feed. Traditional harvesting methods are inefficient, laborious, and time-consuming; hence, there is a need to explore more convenient and efficient techniques. This study assessed preferential selection and feeding behavior of desert locusts to identify trap plants that could attract and aggregate them for easy harvesting. Four trap plants (cowpea, finger millet, sorghum, and amaranth) and four repellent plants (neem, pencil cactus, garlic, and cayenne red pepper) were evaluated through multiple-choice experiments. A randomized complete block design involving mature adult, immature adult, and hopper stages of desert locusts was used. Analysis of variance was used to determine the effects of repellent and trap plants on feeding preferences of desert locusts. Mean differences between treatments at p < 0.05 were separated using post hoc Tukey's honestly significant difference. Cowpea as the most preferred trap plant attracted 62.7%, 70.7%, and 76.9% of mature adult, immature adult, and hopper locust stages, respectively. Neem exhibited the most potent repellent effect and attracted no desert locusts for feeding. Neem repelled locusts, thereby reducing infestation and damage of cowpea as a pull plant when both plants were grown in the same pot in a “push–pull” system. The push–pull attracted 3.7%, 24.3%, and 7.8% of mature adult, immature adult, and hopper locust stages, respectively. However, cowpea attracted large numbers of locusts (96.3% mature adults, 75.7% immature adults, and 92.2% hoppers) when grown separately from neem. These findings provide valuable insights on the potential of exploiting traps and repellents to enhance aggregation and harvesting of desert locusts as food and feed.