Effect of Cropping Systems on the Dispersal of Mycotoxigenic Fungi by Insects in Pre-harvest Maize in Kenya

Maize productivity has remained low and has worsened in the wake of a changing climate, resulting in new invasive pests, with earlier designated minor pests becoming major and pathogens transported by pests and/or entering their feeding sites. A study was conducted in 2021 in Kisumu and Makueni counties, Kenya, to determine how different maize cropping systems affect insect diversity, insect damage to maize, and their ability to spread Aspergillus spores in pre-harvest maize. The field experiments used a randomized complete block design with the four treatments maize monocrop, maize intercropped with beans, maize-bean intercrop with Trichoderma harzianum, and push-pull technology. The fall armyworm Spodoptera frugiperda (J.E Smith) (Lepidoptera: Noctuidae) was the most damaging pest in the two regions. The push-pull and the maize-bean intercropping technologies significantly reduced the maize foliage and ear damage caused by the Fall armyworm. Beetles passively spread mycotoxigenic Aspergillus spp. and Fusarium verticillioides on pre-harvest maize. Maize weevils, Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae) and Carpophilus dimidiatus Fabricius, 1792 (Coleoptera: Nitidulidae), earwigs, Forficula spp. L. (Dermaptera: Forficulidae) and carpenter ants, Camponotus spp. L. (Hymenoptera: Formicidae) carried the highest number of spores on their exoskeletons. The study stresses the role of insects in the spread of fungi on pre-harvest maize and their possible control by intercropping and other cropping technologies.