Parasitism and Damage Caused by Loranthaceae to Subsistence Fruit Trees Growing Alongside Cocoa Trees in Bonoua, South-East, Côte d’Ivoire

Abstract

In Côte d’Ivoire, parasitism caused by the Loranthaceae family poses a serious problem for cocoa plantations. These hemiparasitic plants colonise various trees, whether wild or cultivated, with impacts that vary from case to case. This study aimed to identify the species responsible and assess the degree of infestation of subsistence fruit trees associated with cocoa trees in Ono and Wehou in the Bonoua area. The study was conducted from March to August 2025. Surveys were conducted in 50 m x 50 m plots, where the circumference, height and parasite load of each individual were recorded. Four species of Loranthaceae were identified: Phragmanthera capitata, Tapinanthus bangwensis, T. buntingii and T. sessilifolius. The collection of T. buntingii represents the first record for the flora of south-eastern Côte d’Ivoire. These parasites affect 41 fruit species (32 genera, 16 families), mainly within the Anacardiaceae, Annonaceae, Fabaceae, Malvaceae and Rutaceae. T. bangwensis predominates (24 400 clumps, representing 52.58 % of the total infestation) and exerts pressure on 33 host species (80.49 %), followed by P. capitata (13 804 clumps distributed across 21 hosts). The mean incidence (33.30 ± 10.45 %) and severity index (27.55 ± 11.66 %) differed significantly between the two sites. In Persea americana, Spondias mombin and Cola nitida, severity was high, with respective percentages of 58.96 %, 52.19 % and 50.08 %. A close correlation was observed between infestation parameters and the morphometric development of the hosts. To ensure the sustainability of cocoa agroforestry, selective pruning of large-trunked and tall trees, which are the main sources of infestation, is essential.