Although no evidence of CRB life stages was present in these biosolid accumulations, it was deemed essential as part of the response and eradication effort to determine if these materials could support larval development. Within the CRB infestation zone on O'ahu are large accumulations of biosolids, the solid end product of wastewater treatment. In addition, accumulations of green waste or other suitable material for CRB oviposition and larval development are routinely monitored within the current infestation zone and are removed or sanitized when CRB life stages are present. Ongoing delimiting and monitoring surveys using ground and aerial traps provide both metrics of the CRB population and the removal of adults from the environment. The three larval instars feed on this organic material, further breaking it down, and the beetles are not considered damaging during these life stages.Ī breeding population of CRBs was discovered in O'ahu, Hawai’i, in 2013 ( 5), leading to the implementation of a large, multi-agency response and eradication effort. CRBs oviposit in decomposing plant material or soil with high organic content. Tree death may occur if the meristem is sufficiently damaged. Adult beetles burrow into palm crowns to feed on sap, causing foliar damage known as “V-cuts” to unfurled fronds. Coconut palm ( Cocos nucifera) appears to be the preferred host of CRB, although oil ( Elaeis guineensis), date ( Phoenix dactylifera), and numerous ornamental palm species are also common hosts ( 2– 4). The coconut rhinoceros beetle is a damaging pest of numerous palm species, particularly outside its native range ( 1, 2). These trials demonstrate a potentially novel approach to managing pest populations of O. In choice experiments, gravid females showed no oviposition preference for media hydrated with water or 2× Epsom salt but did avoid ovipositing in mulch rehydrated in 5× Epsom salt. Similar to the acute exposure, eggs exposed to 5× levels did not hatch, or the first instar died soon after emergence. Chronic exposure (eggs reared on mulch through pupation) to Epsom salt at these same rates resulted in significantly delayed instar development and reduced adult biometrics at both 1× and 2× levels. A similar trend in survival was observed in subsequent experiments using a horticultural grade of Epsom salt (MgSO 4) at 1×, 2×, and 5× the recommended application rate. Acute (7 days) exposure to mulch rehydrated in solutions of CaCl 2, KCl, MgCl 2, or NaCl increasing in concentration from 0 to 0.7 M resulted in increased mortality, with concentrations > 0.5 M generally being 100% lethal to both first and second-instar larvae. rhinoceros life stages were acutely and chronically exposed to several metal salts at increasing concentrations to determine the impact of these salts on survival, development, and oviposition behavior. To determine if the elevated metal salts present in the biosolid waste was responsible for this observation, O. Biosolid waste within Hawaii’s infestation zone, however, was determined to inhospitable to O. rhinoceros larvae develop in materials rich in organic materials such as green waste and animal manure. Oryctes rhinoceros (Coleoptera: Scarabaeidae) is an invasive pest of palms in the Pacific Region, including Hawaii, for which limited management options are available. Agrosecurity Laboratory, Department of Plant and Environmental Protection Sciences, College of Tropical Agriculture and Human Resources, University of Hawai’i, Honolulu, HI, United States.
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