Insect and avian threats to the industrial production of balanites fruit in Eritrea

Balanites fruit pulp and seed kernel contain considerable amount of steroidal saponins, which are used as raw material for the production of pharmaceutical drugs. However, insect and avian pests are the key limiting factors in balanites production. This study was conducted to record the causal insect and avian pests and level of their infestation. Balanites fruits fallen on the ground were collected at regular intervals for two fruiting seasons at Keren, Eritrea. The fruits were put in polybags and stored at room temperature. The emerging insects were counted and percent infestation was calculated. The insects identified were balanites stone borer, Eublemma (= Eupsoropsis ) robertsi (Lepidoptera: Erebidae) and carob moth, Apomyelois (= Ectomyelois ) ceratoniae (Lepidoptera: Pyralidae). Eublemma robertsi larva consumed the kernel and bored into the stone with one exit hole (ca. 3 mm) at pre-pupal stage whereas A. ceratoniae larvae infested and contaminated fruit pulp with faecal waste. More than 70% of fruits collected during October and November were infested by E. robertsi and oviposition of 1–3 eggs were found on 73% of examined fruits. Damage from A. ceratoniae was unnoticeable in field-collected fruits but larval infestation was observable after one month of storage. The speckled mousebird, Colius striatus (Coliiformes: Coliidae), was the most frequent avian visitor, which not only nibbled on fruits attached to branches but also caused drop of fruits to the ground. Fruit damage caused by birds ranged 58 to 95% during the two fruiting seasons.