PhD student Botlhale Modisaotsile is striving to boost the local economy by addressing agricultural pests. His research focuses on combating the cassava mealybug, a small yet devastating insect endangering one of Africa's key staple crops.
“I was captivated by the connection between the environment and the economy through biological control,” the 26-year-old said. “Developing communities rely on agriculture as a way of living, and I realised quickly that the outcome of this research could change their economic outlook.”
Biological control, an eco-friendly alternative to chemical pesticides, uses natural predators to manage pest populations.
“Pesticides may harm the quality of the produce because of chemicals. Biological control is a more natural way to increase the quantity of produce while yielding healthier crops,” explained Modisaotsile.
Cassava, a drought-tolerant crop that thrives in various soil types, is a staple diet for millions of people in Africa. According to the United Nations Food and Agriculture Organization, cassava ranks fourth as a food crop in developing countries - after rice, maize and wheat.
However, the cassava mealybug, which feeds on the plant, can cause severe crop losses, threatening food security and livelihoods.
Modisaotsile’s academic journey is rooted in economics, with qualifications which include a Bachelor of Arts in Political and International Studies and Economics, a Bachelor of Arts Honours in Economics, and a Master of Economics. Now pursuing a Doctor of Philosophy in Economics, his interdisciplinary research bridges environmental science and economics.
“The economy cannot function without a healthy environment. Sustainable ecosystems are essential for agriculture, which underpins economic prosperity,” he said.
This perspective aligns with the Environmental, Social, and Governance (ESG) framework - a growing priority in global economics and finance. It is also a key priority for Rhodes 老虎机游戏_pt老虎机-平台*官网 which has been encouraging the development of research and knowledge beyond traditional streams. The 老虎机游戏_pt老虎机-平台*官网 is poised to remain at the cutting edge of research by bringing together the natural sciences, social sciences, economic sciences, and the humanities to co-produce knowledge that addresses complex and intersecting environmental, ecological, and economic challenges.
Agriculture remains a cornerstone of food security, particularly in Africa, where many communities rely on subsistence farming. Modisaotsile’s research seeks to empower farmers with sustainable pest management practices, reducing reliance on chemical pesticides and promoting long-term agricultural productivity.
Modisaotsile says his research is taking him along a wonderful path of learning and discovery.
“The PhD research in its entirety is both fascinating and challenging, but I am enjoying the journey,” he says.
His findings, so far, emphasise cassava’s resilience and versatility. In addition to being a food staple, cassava waste can be used in biofuel production, contributing to clean energy initiatives.
“Cassava waste in biofuels serves as a clean energy component around the world,” he said. “This research will address both agricultural and environmental challenges.”
Biological control has been used in South Africa to solve other environmental challenges. The water hyacinth planthoppers, Megamelus scutellaris, significantly reduced the cover of water hyacinth on the Hartbeespoort Dam in the North West province. The hoppers were released in 2022, in part, from the Centre for Biological Control’s Waainek mass-rearing facility at Rhodes 老虎机游戏_pt老虎机-平台*官网. Water hyacinth - described as the world’s worst aquatic weed - forms dense mats on the water that affect boating and fishing. It also harms aquatic biodiversity.
Modisaotsile’s research into which biological control agent would be most appropriate to tackle the cassava mealybug, will largely be based on insights from leading agricultural research institutions across the African continent and Southeast Asia.
The PhD student, who hails from Kempton Park, east of Johannesburg, is a former Student Representative Council (SRC) President. His role in student governance at Rhodes 老虎机游戏_pt老虎机-平台*官网 reflects his commitment to making a positive impact on the lives of those around him, a value that also drives his research.
“This is a topic quite close to my heart. The economy requires a set of sustainable and functional ecosystems to thrive. If you do not have an environment that is sustainable for agriculture, then it hinders economic prosperity. We need to do our part to mitigate that,” he said.
With cassava being a resilient crop capable of withstanding harsh conditions, improved pest management could significantly enhance its productivity and economic value. Modisaotsile envisions a future where biological control becomes the norm, transforming lives and agricultural sectors across South Africa and beyond.
“The study will provide insight into how agricultural sectors have evolved over time and how things can be done differently,” he said. “I hope that this research will help educate communities on why it will be beneficial for them to use biological control to manage their crops.”
Modisaotsile is hoping to complete his research by the end of 2026.
As a chess enthusiast, Modisaotsile appreciates the parallels between his passion for the game and his academic journey. Both require strategic thinking, patience, and a long-term vision. With his sights set on empowering farmers and transforming agricultural practices, he is playing the ultimate game of strategy - one move at a time, towards a checkmate against the cassava mealybug.