Pest of the Month – February 2018
New exotic ornate pit scale species found in Hawaii Island
Asterococcus Prob. yunnanensis
Mahalo to the Hawaii Dept of Agriculture Plant Pest Control Branch, and Janis Matsunaga for the information and photos in this post. For more details, see: “Asterococcus sp. prob. yunnanensis Borchsenius (Hemiptera: Cerococcidae): A New Exotic Scale Insect Pest in Hawaii and the U.S.,” October 2016. https://hdoa.hawaii.gov/pi/files/2017/01/Asterococcus-yunnanensis-flyer.pdf
Distribution: This scale probably originated in China. In Hawaii, this new scale pest is so far found only in Waimea, Hawaii Island.
Hosts: In Waimea, hosts include Rhaphiolepis indica, Gardenia taitensis, and Rhododendron sp. (three different plant families). Elsewhere, hosts in three other family also are known.
Damage: Ornate pit scale feeding can result in major levels of sooty mold, which in turn causes twig bieback, defoliation, and sometimes plant death.
Control: Scale problems in general can be managed through a combination of monitoring for both the pest and effects on plant health, optimizing plant health, protecting natural enemies, and hiring a professional to apply narrow-range oils or insecticidal soaps that are more effective against scale pests.