Effect of spatial arrangement of push-pull companion plants on fall armyworm control and agronomic performance of two maize varieties in Ghana

Abstract

Maize (Zea mays L.) production is constrained in Ghana by declining soil fertility, erratic rainfall and the recent fall armyworm invasion. We hypothesised that adopting push-pull farming practices would reduce infestation and damage of maize by fall armyworm, while increasing maize yield. We conducted field experiments at two sites over two cropping seasons to evaluate the effects of spatial arrangements of push-pull companion crops on fall armyworm infestations and grain yield of maize. The experiment was arranged in a split-plot design with variety (Abotem and Opeaburo) as the main plot and fall armyworm treatment options (1 row maize and 1 row Desmodium [conventional push-pull]; three maize rows before one row of Desmodium [modified push-pull]; synthetic chemical and no treatment [control]) as a subplot. Results showed that, regardless of location or maize variety, both conventional and spatially modified push-pull companion cropping significantly reduced fall armyworm infestations under all seasons, as compared with the control. The push-pull companion cropping systems reduced the mean maize damage score of fall armyworm by 168%, compared with the control. Additionally, both conventional and spatially modified push-pull companion cropping significantly increased maize grain and biomass yield by 46.80% and 51.11%, respectively, irrespective of the maize variety compared with the control. The mean damage score, biomass and grain yield of conventional push-pull and modified push-pull were not significantly different. The fall armyworm infestation was decreased by 14.61% in the major season compared with the minor cropping season. This study provides novel evidence of the effectiveness of push-pull farming practice in reducing fall armyworm infestation and damage, and in increasing maize yield in Ghana, which has a different ecosystem to East Africa, where push-pull was developed. Further, it provides critical evidence of the effectiveness of a spatial modification of the push crop in relation with the main crop against the fall armyworm.