Re-evaluation of biocontrol agents released for Schinus terebinthfolia (Anacardiaceae) in Hawaiʻi 70 years later

Schinus terebinthifolia (Anacardiaceae) is locally known in Hawaiʻi as Christmas berry or wilelaiki. This shrub is native to Brazil, Argentina, and Paraguay and was introduced to Hawaiʻi prior to 1911 for ornamental purposes. Since its introduction, it has spread across all the major Hawaiian Islands where it is found in dry lowland to mesic forest areas. In 1954, Hawaiʻi Department of Agriculture identified three potential biological control agents from Brazil which were released to control Christmas berry: Lithraeus atronotatus (Coleoptera: Bruchidae), Episimus unguiculus (Lepidoptera: Tortricidae) and Crasimorpha infuscata (Lepidoptera: Gelechiidae) with establishment of two of the agents: L. atronotatus and E. unguiculus. Since its release, E. unguiculus has provided minimal control of Christmas berry stands. Monthly surveys across 3 sites on Oʻahu with elevation and rainfall gradients were done to determine the relative abundance of E. unguiculus. Partial lifetable studies were conducted to determine mortality factors to identify potential key factors limiting the success of this biological control agent. This work is part of a larger study to determine factors that impact success and failure of biological control agents of weeds and insects in Hawaiʻi.