RES 062 Draft 01 2016-2018 - Laserfiche WebLink

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lighting the need for biosecurity measures focused on plant diseases to prevent additional importations. Such measures ;, 114. �J ' ' would also prevent further spread of this disease statewide and beyond. Analyses of DNA from thousands of fungal isolates , . ,` suggests similarities with the Caribbean group of Ceratocystis (most similar to Species A) and the Asian group of Ceratocys- �i, * f tis (most similar to Species B). There remains a critical need • t to definitively identify the genetic relationships of the Hawai'i s t g` species to other Ceratocystis species, in order to understand ,} : t where these species are from, what host plant material they en- tered on, what additional plant species might be vulnerable to •t� r• ''f attack, and what additional biosecurity measures are needed to restrict entry of other host plant species. There are several suspected vectors for the spread of ROD, In some areas like this forest although the relative importance of each is not known. The in Puna, nearly all of the 'ohi'a disease can be spread by people moving infected materials to have died from ROD, and there ROD-free areas —for example the movement of infected 'ohi'a are few if any 'ohi'a seedlings logs for posts or firewood, or 'ohi'a plants for landscaping or emerging among the invasive restoration. Certain Ceratocystis spore types are "sticky" and plants in the understory (LB. can be transported on cutting tools such as machetes and Friday photo) chainsaws, which can spread the disease when used on unin- fected trees. Ceratocystis also produces highly durable spores that are long-lived under a variety of environmental conditions. Researchers also suspect that the disease is spread by wind and movement of infected sawdust called frass that is created when wood boring beetles bore into infected, dying, or dead 'ohi'a trees. The resulting wood frass can contain fungal spores that can be spread by wind. Initial wind transport modeling suggests that infected frass can be transported for many miles, al- though it is not clear how much of the inoculum is needed to infect a tree. Following transport, Cera- tocystis-laden dust or frass can land on 'ohi'a where it may enter an 'ohi'a tree through aboveground wounds, or become incorporated within surrounding soil where it may enter trees through the root system. Ceratocystis has been detected in soil near infected trees, and this soil can be spread by shoes and vehicles that trap and transport spores to new locations. The fungus can remain viable for at least a year in dead wood, although it is not yet clear how long after a tree dies or is harvested before the material no longer contains living, infective spores. Kiln-dry- ing wood at temperatures greater than 130°F kills the fungus. Moving any 'ohi'a wood product that has not been thoroughly kiln-dried may pose a risk. The Ceratocystis fungus and resulting spores can also persist in soils, and so transport of soils or live plants in unsterile media or soil should be avoided. Potted 'ohi'a plants also pose a risk and should not be moved into disease free areas. To this end, the Hawai'i Department of Agriculture (HDOA) instituted an interim rule in August 2015, which bans the movement of Myrtaceae plants, plant parts, and soil from Hawai'i Island to other islands in the State without a permit. In 2016, HDOA went through formal rulemaking to make the interim rule perma- nent. To date, there are no ROD-related interstate or foreign export restrictions for the protection of related Metrosideros species outside of Hawai'i including Samoa, Fiji, New Caledonia, and New Zealand. Current research efforts urgently seek to understand how environmental conditions may be associated with stands of ohi'a impacted by ROD, with a focus on geology, soil types, climate, and 3