Aerial mapping of the Peruvian Chira Valley banana production system to monitor the expansion of Fusarium wilt caused by Tropical Race 4

Abstract

The recent incursion of Fusarium wilt of banana (FWB) caused by TR4 threatens banana production in the Chira Valley of Peru. To develop a management strategy, we mapped the entire production area from the air. During 12 flights at an altitude of 610 m (2,000 ft) we gathered 133,700 images in a timeframe of two weeks and constructed an orthomosaic map of 73,000 ha. This unveiled the complex logistic network across the banana-producing region, comprising 150 km of primary roads as well as numerous secondary and tertiary unpaved paths through and bordering banana plantations. Moreover, the Poechos reservoir – with a total length of 450 km - feeds the entire Chira Valley irrigation system, which could further exacerbate TR4 expansion. Using georeferenced landscape details (digital terrain model, DTM), we determined areas prone to flooding, which is also relevant for disseminating TR4. Analyses of the maps resulted in the identification of many suspect areas for direct sampling and subsequent analyses to study the expansion of TR4. At four locations, we confirmed two cases and by June 8, 2023, a total of 207 cases were reported. We conclude that TR4 is a serious threat to the entire region which exports approximately 25% of the global organic bananas.