Performance of Push–Pull Technology in Low-Fertility Soils under Conventional and Conservation Agriculture Farming Systems in Malawi

Abstract

Push–pull technology (PPT) is one of the most viable low-cost agroecological practices that reduces the effects of insect pest infestations (e.g., stemborer) and parasitic weeds (e.g., Striga) in croplands. PPT was evaluated in low-fertility soils and two farming practices, minimum-tilled conservation agriculture practice (CA), and conventionally tilled practice (CP), in contrasting agroecological zones at the Chitedze, Mbawa, and Chitala stations in Malawi. Stemborer and Striga infestations were also investigated and the suitability levels of two Desmodium species. Farmers’ perceptions of PPT were gathered through a focus group discussion. The performance of PPT varied significantly between treatments, sites, and years on grain yields and the number of cobs that could be assigned to soil attributes. Significant variations were found in the number of exit holes, stemborer damage severity, and the number of Striga-affected plants with severe infestation. In Chitedze, CP recorded significantly shorter maize plants by 14.1, 11.6, and 5.8 cm than CP–PP, CA, and CA–PP, respectively, in 2016–2017. There were no significant differences in plant height between CP–PP, CA, and CA–PP. Similar results were also found in 2017–2018. Focus group discussions among farmers attested to up to 70% reductions in Striga weed and stemborer pests under PPT over the two seasons. Farmers who used push–pull technology reported a 45–50% yield increase. Push–pull was also perceived as a technology that improves soil fertility and controls soil erosion. The study presented the importance of soil physicochemical properties in the performance of the technology, as supported by the high occurrence of Striga asiatica in the country and the low suitability of Greenleaf Desmodium. Results reaffirmed the technology’s agronomic benefits in productivity, pest management, plant vigour, and Striga control. The cost of labour was described as a challenge, and research to identify more suitable Desmodium species is needed. The current study suggests the release of the technology in Malawi, emphasizing the inclusion of Desmodium and Brachiaria as animal fodder for the adoption of the technology.

The push-pull intercrop Desmodium does not repel, but intercepts and kills pests

“…This cropping strategy reduces infestations of various Lepidoptera pests, including Chilo partellus and Busseola fusca, as well as Spodoptera frugiperda, a polyphagous invasive pest that is ravaging maize and vegetable production and threatens food security in sub-Saharan Africa 14,15 . Strongly propagated by institutions and governments [16][17][18][19][20][21] , this intercropping strategy has found widespread adoption in East Africa. As a hallmark of sustainable pest control, it also serves as a tremendous source of inspiration for intervention strategies in other cropping systems.…”

Push-pull cropping system soil legacy alter maize metabolism and fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) resistance through tritrophic interactions”

“…root and shoot tissues usually remain in and on the ground after harvest and so contribute to elevated organic matter in the soil. In contrast, conventional monocultures, speci cally those of maize, lack all of these attributes and usually negatively impact soil properties (Drinkwater et al, 1998;Niassy et al, 2022). What is surprising, however, is that this improvement of plant growth is accompanied by a remarkable increase in maize plants' expression of direct and indirect resistance in push-pull soils.…”

Farmers’ perceived pathways for further intensification of push-pull systems in Western Kenya

“…According to farmers, inadequate technical knowledge, high initial capital, and high initial labor requirements have constrained the adoption of the push-pull farming system. As with other knowledge-intensive technologies, acquiring this requisite knowledge has remained a challenge, limiting push-pull adoption (Midega et al, 2016;Niassy et al, 2022). Specifically, high costs of desmodium and brachiaria seeds put the initial capital outlay beyond the reach of many smallholder farmers (De Groote et al, 2010).…”