More flowers in sugarcane fields in Africa: an urgent need to attract and preserve natural enemies to increase the biological control of sugarcane pests

Abstract: Most sugarcane areas in Africa belonging to small and large farmers as well as sugar
companies are generally poor in terms of biodiversity due to the monocropping system used
with conventional agricultural and harvesting practices while they encounter many pest
problems and economic yield losses. Particularly, flowering plants, flower strips and natural
vegetation that provide shelter, nectar and pollen for many useful insects are missing along
arable fields. Integrated Pest Management (IPM) in sugarcane remain conventional with the use of resistance varieties, pesticides and augmentative biological control. Conservation biological control is not yet used as a long-term strategy to reduce pest infestations. In Tanzania, we have discovered the importance of using flowering plants such as Tithonia diversifolia to not only help controlling the Yellow Sugarcane Aphid Sipha flava but also the white grub Cochliotis melolonthoides, a key pest of sugarcane in Tanzanian sugarcane fields. Regular surveys, observations and collections of different predators such as ladybirds, hoverflies, lacewings, long-legged flies, spiders and scoliid wasps in T. diversifolia shrubs along sugarcane fields has proven the importance of these banker plants for the abundance and activity of these natural enemies. We then concluded that more flowering plants are needed in sugarcane fields to increase pest control and could be integrated in future sugarcane crop protection in African sugar producing countries.