Fall armyworm (Spodoptera frugiperda, FAW) was recently introduced to African landscapes and the insect pest has been chewing its way through many of the continents staple crops since. First detected in central and western Africa in early 2016, FAW larvae were initially assumed to be those of a native species. By late 2016, the pests true identity had been confirmed and the outbreak had spread to eastern and southern Africa.
In 2017, farmers in CCRP countries Niger, Kenya, Tanzania and Uganda were severely affected. FAW is native to tropical and subtropical regions of the Americas. The pest has a broad host range that includes nearly 100 plant species, but it prefers graminaceous plants. FAW is ravenous, prolific and the moths can fly for long distances. Larval feeding can cause extensive defoliation in maize and injure other parts of the plant including the whorl and developing ear.
Given its habits, FAW outbreaks are likely to continue to pose a threat to food security and livelihoods until effective management strategies are implemented. A key question for CCRP farmers and researchers is what integrated pest management options exist to battle the invasion. Sorghum cultivation may be part of the answer. FAW is known to prefer maize over sorghum, and findings from CCRP research confirms that sorghum was less damaged in the recent growing season. During the Eastern Africa community of practice meeting in May, several groups of meeting participants visited different sites within the farmer research network (FRN) area of the FRN-NGO project, where large numbers of farmers were testing sorghum varieties produced through prior CCRP research. Farmers were impressed by the performance of their experimental sorghum crops, particularly in the face of FAW damage as well as drought stress, and the visitors were impressed by the farmers knowledge and enthusiasm.
In post-meeting conversations, a plan was hatched to conduct a survey to formalize the observation that sorghum was less damaged than maize and to begin to understand some of the contributing factors. Over the course of a few days, a simple survey design was refined with input from the research methods support (RMS) team, the regional team, the sorghum project team and FRN-NGO. Ten young farmers, equipped with mobile phones and training from a member of the multi-purpose legume project team, served as enumerators and quickly fanned out to collect data. The farmer-enumerators captured survey responses on their mobile devices using Open Data Kit and the results were rapidly analyzed by the RMS team. Of the1,271 farmers interviewed, 1,194 grew maize and sorghum and observed FAW damage. Of these, 83% assessed the damage as worse on maize. Only in one high-altitude region was sorghum not more resistant than maize.
Planting time seemed to influence FAW damage. With early and normal planting (relative to the start of the rains), sorghum was less damaged than maize. The advantage of sorghum over maize disappeared, however, when the crops were planted later. All of the types of maize varieties being grown (local, hybrid or both) seemed to be equally susceptible to FAW. The FAW advantage of sorghum was higher with traditional than with new varieties. There was no difference in relative susceptibility of maize and sorghum when they were intercropped compared to being grown separately. More observations will be made in the next season on the damage caused by the pest to sorghum and maize crops.
Farmers declared 2017 to be the Year of Sorghum, with the effects of drought and FAW rendering sorghum a better bet than maize. Maize remains the preferred food of many Kenyans, but with drought and FAW pressure likely to remain serious constraints to maize production in future seasons, farmers may be motivated to diversify their crop portfolios to include other staples like sorghum. The FRN-NGO project worked with 900 farmers in the recent season to test a new suite of sorghum varieties produced by the CCRP sorghum project, and such trials will continue and expand to a broader range of sorghum germplasm as well as other key crops that may provide greater resiliency and nutritional benefit.
Meanwhile, the CCRP thematic group on pest and disease management has been considering other work that can complement the deployment of sorghum to reduce farmers risk due to FAW. CCRP research has led to the identification of botanical pesticides that might be tested for effectiveness on young FAW larvae. Other researchers in the field are looking for additional alternatives, such as natural enemies that might provide biological control. These options may be of interest to FRNs looking for ecological alternatives for FAW management. An FRN offer an evolving platform for farmers, researchers and development practitioners to share knowledge and learn about problems and opportunities, source possible options to cope with challenges and capitalize on ideas, and to build a shared understanding as their efforts progress.
In the case of the FAW crisis, one issue will be to ensure that farmers can distinguish between damage caused by FAW and by the maize stalk borer, to better understand the two problems and to identify workable ways of managing each of these pests.