Hawaii Department of Agriculture (HDOA) has requested that the green waste generated from pruning or removing a Lobate Lac Scale (LLS) infested plant be left at the site where it originated to reduce the risk of spreading this pest around Oahu. For example, chipped green waste from a tree can be left as mulch under the tree that was pruned. Smaller green waste, like hibiscus branches, can be bagged in dark plastic and left in the sun in an out-of-the-way corner of the property for a few days. The heat generated in the bag will hopefully be sufficient to “cook” the LLS. Leaving any of the green waste out in the sun for a month or so would probably work as well. Unfortunately, research on the life cycle of LLS and how long the different stages last doesn’t exist, so this is just a best guess. It is certainly better than doing nothing. LLS is sufficiently established on Oahu to be impossible to eradicate, but landscape professionals are the first line of defense in slowing it down.
Most importantly, because LLS has only been found on Oahu thus far, DO NOT MOVE INFESTED MATERIALS BETWEEN ISLANDS. As a reminder, all plants and propagative plant material require inspection by the HDOA Quarantine Branch before moving between islands. If found infested with LLS, it will require treatment to exterminate the pest before it can be shipped.
Carol Kwan is the President of Carol Kwan Consulting, a Certified Arborist, and the Secretary of Aloha Arborist Association.