New menace to horticultural and staple food crops: Identification of an emerging thrips pest (Thysanoptera: Thripidae) infesting cassava

Abstract Cassava ( Manihot esculenta Crantz) is a key staple crop in Central and Western Africa, yet its production in the Democratic Republic of Congo (DRC) is increasingly threatened by insect pests. Among these, an emerging “cassava thrips” has caused substantial yield losses, but its identity remained unresolved. This study aimed to determine the species identity of this pest and assess its host range using an integrative morphological and molecular approach. Thrips were collected from cassava fields in the DRC and from Tithonia diversifolia in Kenya. Morphological examination of slide-mounted specimens revealed diagnostic characters consistent with Frankliniella borinquen Hood, including antennal segment III morphology, body colouration, and metanotal and abdominal features. Molecular analyses targeting ITS2 and mitochondrial COI-5P markers were performed, with ITS2 providing limited resolution, whereas COI-5P sequencing unambiguously confirmed species identity. Phylogenetic reconstruction and genetic distance analyses demonstrated strong conspecificity among F. borinquen samples and clear divergence from other Frankliniella species. The presence of F. borinquen on both cassava and T. diversifolia suggests a broader host range and potential host-shift dynamics, possibly facilitated by agricultural intensification and proximity of host plants. The establishment of F. borinquen on cassava raises concerns for crop productivity and food security, particularly given the genus’s potential as vectors of tospoviruses. These findings provide a foundation for monitoring, risk assessment, and the development of targeted, sustainable management strategies for this emerging pest.