Impact of push–pull cropping system on pest management and occurrence of ear rots and mycotoxin contamination of maize in western Kenya

Abstract

Push–pull involves intercropping of cereals with Desmodium as a “push” crop and planting Napier grass/Brachiaria as the “pull” crop at the border. The technology has been reported to effectively control stemborers, striga weed, and fall armyworm (FAW), and to improve soil nutrition, resulting in increased grain yield. This study evaluated the impact of stemborer and FAW management using this technology on incidence of maize ear rots and preharvest contamination of grains with aflatoxin and fumonisin in western Kenya. The study was conducted during three cropping seasons on maize grown under the push–pull system and as a monocrop. Incidence of stemborer and FAW damage was determined as percentage of damaged plants, while incidence of ear rots was determined as percentage of ears with symptoms. At harvest, fungi were isolated from kernels and aflatoxin and fumonisin were quantified using enzyme‐linked immunosorbent assay. Stemborer and FAW damage was significantly (p = .001) reduced by over 50% under the push–pull system. There was also a significant (p < .001) reduction in the incidence of Fusarium verticillioides (60%) and Aspergillus flavus (86%), which was reflected in a reduced incidence of ear rots (50%) with the push–pull system (p = .001). Fumonisin in maize from push‐pull farms was significantly (p = .048) reduced (39%) but the technology had no significant (p > .05) effect on aflatoxin. The study showed that push–pull is an effective strategy for managing maize ear rots and fumonisins, and therefore could play a role in improving food safety among smallholder maize farmers in the region.

Long-term maize-Desmodium intercropping shifts structure and composition of soil microbiome with stronger impact on fungal communities

“…Moreover, the technology provides other ecological benefits contributing to improved cereal crops yield, including nitrogen fixation by Desmodium, soil structure improvement and a mulching effect in the fields. Finally, the technology reportedly reduced the incidence of human pathogenic fungal toxins in maize kernels (Njeru et al 2020;Owuor et al 2018). In addition, both Desmodium and the trap crops are a reliable source of animal fodder, particularly in drought periods, as farmers do not uproot them between farming seasons (Khan et al 2010).…”

Effectiveness of Push–Pull Systems to Fall Armyworm (Spodoptera frugiperda) Management in Maize Crops in Morelos, Mexico

“…Urb. Recently, Njeru et al [ 39 ] reported a reduction of more than 50% of fall armyworm infestation in the same Push–Pull system. In the current study, the greatest reductions in Fall Armyworm incidence and severity were recorded in the MIIC, TC, MIID, MC, MIIT and MD systems ( Table 3 ).…”

Long-Term Maize-Legume Intercropping Shifts Structure and Composition of Soil Microbiome with Potential Impacts on Ecosystem Services and Food Safety

“…The maize-desmodium push-pull intercropping system, originally developed to reduce stem borer impacts , has evidently very pronounced below-ground bene ts, including control of the parasitic weed striga, increase in soil carbon and fertility through perenniation and nitrogen xation (Khan et al 2016;Midega et al 2018), and a lower incidence of mycotoxin-producing fungal infection (Owuor et al 2018;Njeru et al 2020). By virtue of the long-term cropping plots managed by ICIPE, long-term push-pull and monoculture plots (more than 14 years old) are exquisitely suited for studies on long-term effects of legume intercropping on soil microbiomes.…”

“…Recent papers reported lower incidences of maize ear rot and associated mycotoxins (a atoxins and fumonisins) (Owuor et al 2018) as well as lower rate of infection of maize kernels with Fusarium verticillioides and Aspergillus avus (Njeru et al 2020) in smallholder farmers' push-pull plots compared to monoculture. Push-pull thus appears to promote food safety by reducing the risk of mycotoxins entering the human food chain, although the mechanisms remained unclear.…”

“…Moreover, push-pull technology provides other ecological bene ts contributing to improved cereal crops yield, including nitrogen xation by Desmodium, soil structure improvement and mulching effect in the elds. Finally, push-pull cropping reportedly reduced the incidence of human pathogenic fungal toxins in maize kernels (Njeru et al 2020;Owuor et al 2018).…”