Decontamination of Ceratocystis Pathogens Responsible for Rapid ʻŌhiʻa Death

Abstract

Rapid ʻōhiʻa death (ROD) is caused by two recently described species of Ceratocystis, C. lukuohia and C. huliohia. These fungi are decimating ʻōhiʻa lehua (Metrosideros polymorpha), the keystone native tree species of Hawaiʻi. Viable Ceratocystis propagules can persist in ambrosia beetle frass (Coleoptera: Scolytinae), and movement of the frass may play a key role in the spread of the disease. In order to prevent the spread of ROD, we developed effective and practical surface (e.g., tools and shoes) decontamination methods to be used by researchers, managers, and the public alike. We first tested different household and laboratory disinfectants on the Ceratocystis fungi in culture, and then we applied the effective culture disinfectants to contaminated ambrosia beetle frass. Laboratory-grade ethanol (70, 80, and 95%), Clorox bleach (10%, 0.825% active ingredient [a.i.]), and isopropanol (70 and 91%), were all equally effective at decontaminating cultured C. lukuohia and C. huliohia. Although all concentrations of isopropanol (50, 70, and 90%) and ethanol (50, 70, and 90%) were effective disinfectants of Ceratocystis-contaminated frass, treatments of frass with up to 20% Clorox bleach (1.2% a.i.) were not completely adequate at killing the fungus. These data reveal that bleach is not a sufficient ROD disinfectant when frass is present, and isopropanol or ethanol are the more reliable options.

Seasonal and Elevational Differences by Sex in Capture Rate of ‘Ōpe‘ape‘a (Lasiurus semotus) on Hawai‘i Island

“…After careful evaluation of conditions in Hawai‘i, implementation of enhanced fieldwork protocols, acquisition of personal protective equipment, and personnel training in the proper use of N95 respirators, bat captures resumed in early June 2020. Additionally, throughout our field surveys we followed best available decontamination practices for preventing the spread of Rapid ‘Ōhi‘a Death (ROD), an emergent fungal disease affecting the keystone species ‘ōhi‘a lehua ( Metrosideros polymorpha ), a culturally and ecologically important native tree species in Hawai‘i (Roy et al 2020).…”

The use of semiochemicals for attracting and repelling invasive ambrosia beetles (Coleoptera: Curculionidae) in ʻōhiʻa (Metrosideros polymorpha) forests

“…Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The data and metadata associated with this manuscript are available at https://doi.org/10.5066/P9ALYPF8 (Roy et al, 2022). We acknowledge that our fieldwork took place in the ahupuaʻa of Waiākea in the moku of Hilo, and ʻŌlaʻa in the moku of Puna on the mokupuni of Hawaiʻi, which are the ancestral and traditional lands of the Native Hawaiian people.…”

Ambrosia beetles (Coleoptera: Curculionidae) can directly transmit the fungal pathogens responsible for Rapid ʻŌhiʻa Death

“…Any use of trade, firm, or product names is for descriptive purposes and does not imply endorsement by the U.S. Government. The data and metadata associated with this manuscript are available at https://doi.org/10.5066/ P99TXGKI(Roy et al, 2022). We acknowledge that our fieldwork took place in the ahupuaʻa of Waiākea and Waipunalei in the moku of Hilo, Kalopā and Waipunalei in the moku of Hāmākua, Puʻukapu in the moku of Kohala, and ʻŌlaʻa in the moku of Puna on the mokupuni of Hawai'i Island, which are the ancestral and traditional lands of the Native Hawaiian people.…”