Fungus in the Frass

The first study to implicate ambrosia beetles in Rapid ʻŌhiʻa Death (ROD) has been published by CTAHR researchers and co-authors. Working out of the Komohana Research and Extension Center, the researchers placed 200 frass traps onto ʻōhiʻa trees at four locations on the east side of Hawai‘i Island. Frass is the sawdust and woody droppings produced by ambrosia beetles and other wood-boring insects when they bore into and colonize trees. They identified Xyleborus ferrugineus, a non-native ambrosia beetle, as one culprit in the spread of Ceratocystis lukuohia in the Puna area of the Big Island. C. lukuohia is a tree-colonizing fungus that leads to widespread ROD in ʻōhiʻa lehua trees. Lead author Kylle Roy, who was in PEPS when she did the study, pointed out that other wood-borers may also produce infective frass, and management strategies for the disease can be developed as more is understood about its vectors. Read more about the study here.