Can lessons learned 30 years ago contribute to reducing the impact of the fall army worm Spodoptera frugiperda in Africa and India?

Abstract

The rapid spread of the fall army worm ( Spodoptera frugiperda) across sub-Saharan Africa, and now South Asia, has created surprise and distress to the smallholder farmers of both regions who face hunger and economic stress because of this pest. There has been high-quality support from the international agricultural information sector, but there has also been advice that may not be applicable to the farming systems of smallholder farmers. That comment arises from lessons learned from involvement with a similar pest outbreak of a related pest species in India starting in the mid-80s. Post-rainy season groundnut (peanut) Arachis hypogaea is a high-value crop in the coastal region of Andhra Pradesh. Changes in the management of tobacco crops to the North of the groundnut belt resulted in invasions of Spodoptera litura. The groundnut farmers responded by applying a wide range of insecticides that did nothing to protect their crops from further defoliation. Scientists from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) initiated research that enriched the knowledge of this crop–pest relationship. For instance, they showed that groundnut plants could withstand close to complete defoliation with little loss in yield. Farmers also learned that the cessation of their insecticide regime allowed natural enemies of the caterpillars to take over the management of the pests. They were showed how to enhance the populations of the coccinellids and the birds that were the key predators. ‘Citizen Scientists’ led this process. Non- and quasi-governmental organizations took over the extension process. They were provided with ongoing personal and technical support, for instance, the provision of definitive facts about the high levels of insecticide resistance, encouraging cultural control techniques, and of exploiting natural enemies, including entomopathogens. The involvement of the ICRISAT team later extended into the groundnut fields of South East Asia.