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

Abstract

Maize productivity has remained low and has worsened in the wake of a changing climate, resulting in new invasive pests, with pests that were earlier designated as minor becoming major and with pathogens being transported by pests and/or entering their feeding sites. A study was conducted in 2021 in the Kisumu and Makueni counties, Kenya, to determine how different maize cropping systems affect insect diversity, insect damage to maize, and insects' ability to spread mycotoxigenic fungi in pre-harvest maize. The field experiments used a randomized complete block design, with the four treatments being maize monocrop, maize intercropped with beans, maize-bean intercrop with the addition of <i>Trichoderma harzianum</i> at planting, and push-pull technology. The FAW, <i>Spodoptera frugiperda</i> (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 FAW. Beetles passively spread mycotoxigenic <i>Aspergillus</i> spp. and <i>Fusarium verticillioides</i> on pre-harvest maize. Maize weevils, namely, <i>Sitophilus zeamais</i> Motschulsky, 1855 (Coleoptera: Curculionidae), and <i>Carpophilus dimidiatus</i> Fabricius, 1792 (Coleoptera: Nitidulidae), earwigs, namely, <i>Forficula</i> spp. L. (Dermaptera: Forficulidae), and carpenter ants, namely, <i>Camponotus</i> spp. L. (Hymenoptera: Formicidae) carried the highest number of spores on their exoskeletons. This 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.