The Cocoa swollen shoot disease probably represents today the greatest threat to cocoa production in Côte d'Ivoire. The disease is caused by the Cacao swollen shoot virus (CSSV), a badnavirus transmitted to cocoa by about 15 mealybug species in West Africa. At local scale, the propagation of CSSV outbreaks is closely related to mealybug dispersal behaviors. The ability of barrier crops to stop the disease spread has been demonstrated in Togo and Ghana, yet mechanisms involved are still not elucidated. The present study aims at better understanding these mechanisms by studying mealybug population dynamics in young plantations surrounded by barrier crops. A set of twelve 0.25 ha cocoa plots surrounded by 10 m large hedges of coffee (Coffea robusta) or acacia (Acacia auriculiformis), or without hedges (control plots), was implemented within large CSSV outbreaks in mature cacao plantations, in July and August 2019, near Soubré (South-West Côte d'Ivoire). First counts of mealybug colonies on cocoa and barrier crops were done in September 2019 and February, March and May 2020. From November 2020 to August 2022, populations were assessed monthly using a scoring scale, a score from 0 to 3 being given to each cocoa according to the size of the hosted population. Pseudococcus longispinus and Ferrisia virgata were the first species present on cocoa, but populations remained small until May 2020 with a maximum of 0.5% of trees infested by few mealybugs. These two species have long waxy hairs that allow them to be transported by wind. Although very common in neighboring mature plantations, Formicococcus njalensis populations remained small in young plots. During the period November 2020 - August 2022, F. njalensis was the dominant species on cocoa with 63.8% of the total number of infested trees. F. virgata, Planococcus citri and P. longispinus represented 10.8%, 4.7%, 2.9% of infested trees, respectively. Following results were obtained for the most infested plantation, with coffee barriers. Weighted infestation rate for F. njalensis showed significant variation throughout the period, but without clear seasonal trend, suggesting that other factors than climate may have affected mealybug populations. Maps of infestation and semivariograms showed that F. njalensis population was globally aggregated, meaning that cocoa trees hosting mealybugs were usually grouped. In addition, borders of the plot were more infested than center. suggesting that plot colonization by mealybugs started from coffee barriers. These results were discussed and recommendations given for more efficient barrier crops.