Acta Hortic. 1272. ISHS 2020. DOI 10.17660/ActaHortic.2020.1272.19 XXX IHC – Proc. XI International Symposium on Banana: ISHS-ProMusa Symposium on Growing and Marketing Banana under Subtropical Conditions Eds.: I. Van den Bergh et al. 153 Red rust thrips in smallholder organic export banana in Latin America and the Caribbean: pathways for control, compatible with organic certification M. Arias de López 1 , R.E. Corozo-Ayovi 1 , R. Delgado 1 , B. Osorio 1 , D. Moyó n 1 , D. Rengifo 2 , P. Suárez 2 , A. Paulino 2 , S. Medrano 2 , L. Sanchez 2 , J.C. Rojas 3 , U. Vegas 3 , D. Alburqueque 3 , C. Staver 4 , R. van Tol 5 and L. Clercx 6 1 INIAP E.E. Litoral Sur, Yaguachi, Ecuador; 2 IDIAF, La Vega, Dominican Republic; 3 INIA Sullana, Peru; 4 Bioversity International, Montpellier, France; 5 WUR, Wageningen, The Netherlands; 6 Agrofair Benelux BV, The Netherlands. Abstract Since 2010, red rust thrips (RRT) have become a serious pest in organic export banana plantations, causing yield losses of 30-40%. Although RRT blemishes on banana peel are only cosmetic, exporters apply zero tolerance. During 2014-2017, FONTAGRO co-financed studies on measures to reduce RRT damage in smallholder organic export banana. Research was initially guided by an IPM approach based on thrips population thresholds and linked abiotic factors, in order to schedule practices. Initial studies resulted in a preventive model for thrips management based on the year- round use of transparent bags with 3-mm orifices to protect bunches just as the bell emerges and before bracts open. This approach minimizes losses due to both Chaetanaphothrips signipennis found in Peru and Ecuador and Chaetanaphothrips orchidii common in the Dominican Republic. Experiments to develop scouting methods and establish thresholds suggested three conclusions: C. signipennnis flies very little, complicating trapping even with pheromones; thresholds for economic damage are very low; and scouting is difficult, costly and not practical for decision making. Routine monitoring of losses caused by RRT and other factors should be done during packing. Experiments to test the effectiveness of bagging and the use of applied products to repel or kill thrips showed that bagging alone reduced losses by 90-100% compared to bunches with no bag. Applications of organic products to the bell at bagging and the leaf whorl and the upper bunch stem simultaneously with other bunch practices reduced losses further by 0-8%. Studies of biological control identified predators, parasitoids and entomopathogens which attack different stages of thrips. Preliminary lab and release studies suggest that biological control should be further developed. However, RRT form part of a complex of insect bunch pests, and the use of general or targeted applications should be reviewed to avoid the use of products which reduce beneficial organisms. Keywords: organic banana, biological control of thrips, bio-insecticides INTRODUCTION In Peru and Ecuador, two leading countries globally in organic export bananas, blemished fruits due to red rust thrips (RRT) caused by Chaetanaphothrips signipennis increased sharply from 2011 onwards, reportedly reaching 30 to 40% damaged fruit (Clercx et al., 2015). RRT are found on pseudostems and young suckers, but economic damage occurs when the adult female lays eggs between tender fingers. The nymphs feed on the surface of the peel, causing oozing sap which oxidizes turning rust colored. Fingers with these lesions are rejected during the packing process and are often sold on the national markets. However, although the RRT spots do not affect the fruit quality (Corozo-Ayovi et al., 2017), exporters have established zero tolerance for such damage in European and US markets (INIAP- ASOGUABO-PROMESA, 2013). In conventional export bananas, the use of insecticide-impregnated bags has minimized fruit rejections due to RRT, other thrips and bunch insect pests. However, this practice is not