Hawaii's Invasive Species
They aren’t cute, cuddly or shy. Here are six new—or just pesky—invasive species you should know about.
1. Small hive beetle, roughly one-third the size of a honey bee and native to sub-Saharan Africa. Discovered: Big Island, 2010. Feeds on wax and honey in hives, destroys comb and causes fermentation of honey. What’s being done: mechanical traps and pesticides; biocontrol (introducing a predator) is being researched.
2. Naio thrips, a 2-mm-long insect, either from New Zealand or Australia (unknown). Discovered: Big Island, 2009. The thrips has had a severe effect on the ornamental landscape plant naio; it feeds on its leaves, causing them to form heavy galls. The concern is that it will move into native naio forests. What’s being done: chemical control.
3. Varroa mite, a pinhead-size, red, crablike mite, native to Southeast Asia. Discovered: Oahu, 2007, and Big Island, 2008. Kills wild and managed bee populations by sucking the blood from honey bees and their young. What’s being done: chemical control, traps, cultural controls and biocontrol is in research.
4. Erythrina gall wasp, a gnat-size, brown insect with wings, native to East Africa. Discovered: Oahu, 2005, and has spread statewide. Feeds on non-native and native erythrina trees (including wiliwili), causing the leaves and stems to form galls, which halt normal plant functions. What’s being done: a natural enemy wasp was released in 2008.
5. Ohia rust, a microscopic fungus, likely from Florida. Discovered: Oahu, 2005, and has spread statewide. This particular strain of rust affects plants in the myrtaceae family (of which ohia is one) and has caused huge die-offs of the rose apple. The concern is that another strain will arrive and affect native ohia. What’s being done: No known treatments or control measures available.
6. Nettle caterpillar, a sluglike caterpillar with spines, originally from Southeast Asia. Discovered: Big Island, 2001; Oahu and Maui, 2002. Has stinging spines that cause pain and symptoms similar to man-of-war. Found on plants—grass, ti, palms—common in yards. What’s being done: chemicals and biocontrol; a tiny wasp that feeds on nettle caterpillars was released in 2010.
Sources: Christy Martin, public information officer for Hawaii’s Coordinating Group on Alien Pest Species, and Neil Reimer, chief of the Plant Pest Control Branch for the Hawaii Department of Agriculture.