Some years ago, an Australian native insect called the “macadamia felted coccid” found its way to Hawaiʻi, causing leaf and branch die back, flower drop and sometimes, tree death among Macadamia trees.
Relatively recently, the invasive pest insect became widespread on the Big Island – and of course, this has led to reduced crop yields.
To understand the relationship between macadamia felted coccid infestation level and yield loss, a Dept. of Plant and Environmental Protection Sciences team led by professor Mark Wright and Dr. Rosemary Gutierrez measured yields in various locations and varieties of macnut related to the number of insects infesting these trees over the course of a year.
Their study, Macadamia felted coccid impact on macadamia nut yield in the absence of a specialized natural enemy, and economic injury levels, provide estimates of the economic injury level for macadamia felted coccid – the minimum number of insects infesting a tree – that results in economic loss justifying pest management intervention. It appears in the most recent edition of the international journal Crop Protection.
“This work provides growers with a tool to decide when to apply pesticides, and will optimize the economics of pest management for them,” says Mark. “Right now, we do not have very good biocontrol for macadamia felted coccid, but hopefully will in the foreseeable future.”
He adds, “The Hawaiʻi Department of Agriculture has a promising species in quarantine, and we are collaborating with them to seek permission to release this potentially beneficial biocontrol agent.”
Read more about the macadamia felted coccid, its biology, and management.