New & Noteworthy: Mouflon, Devil Weed, and Myoporum Thrips

posted in: August 2011 | 0

Maui Mouflon? Investigations into how axis deer arrived on the Big Island have turned up one intriguing theory: that at least some of the deer were brought from Maui in exchange for mouflon from the Big Island.

Lending credibility to that suspicion are recent blog accounts and photos of mouflon hunts and a mouflon trophy taken on the slopes of Haleakala, at Arrow One Ranch. The ranch itself advertises “mouflon-hybrid” hunts on its web site,, and says it has more than 1,000 axis deer and mouflon/hybrid sheep.

Keevin Minami, the Department of Agriculture’s land vertebrate specialist, told Environment Hawai`i that no one on Maui has applied for a permit to possess mouflon during his six-year tenure at the department.

Jeff Grundhauser, manager of Arrow One Ranch, told Environment Hawai`i in an email that his ranch does not have pure mouflon, but “we only have cross breed sheep, mostly Texas dall and Barbados.”

“Sometimes there are rams with similar colors like a mouflon,” he said, but he insisted there were no pure mouflon sheep. “The only place you can hunt a pure mouflon sheep now is on Lana`i and maybe there’s a couple of places on the Big Island.”

Devil Weed: The dreaded weed Chromolaena odorata, which the U.S. Army’s environmental crew recently discovered on O`ahu’s North Shore, may not pose a huge threat to Hawai`i’s wild habitats, according to University of Hawai`i forester J.B. Friday.

Although the weed – toxic to humans, livestock, and other plants – is considered one of the worst in the world, it struggles in the shade.

“Personally, I don’t see Chromolaena becoming a major problem in natural areas, but it could be a real problem for ranches,” Friday stated in an email he recently posted on an invasive species list serve.

The weed, which forms dense, monotypic stands, has overwhelmed grazing lands in dry and mesic areas in East Timor, he added, but seemed outcompeted by grass in west areas.

It’s also present in the Philippines “but I never heard it referred to as a problem. Farmers find it easy to clear for cultivation,” he wrote.

The Army, the O`ahu Invasive Species Committee, the state Department of Agriculture, and the Bishop Museum’s O`ahu Early Detection program are mapping the weed’s locations and developing a management strategy.

Although the plant can produce annually 800,000 seeds that can last up to a year in the soil, effective control methods, including several biocontrol agents, exist.

Military training most likely introduced the weed to Hawai`i, according to an article by the Army’s Jane Beachy in the May/June 2011 issue of Public Works Digest. 

Chromolaena is found throughout Asia, Australia, Africa, and Oceania. So far, surveyors have spotted the weed on at least 150 acres on O`ahu.

Eureka! A few months ago a state contractor determined through genetic testing that the Myoporum thrip, a pest that poses a threat to native naio, is originally from Tasmania. That’s according to Cynthia King, an entomologist with the state Department of Natural Resources’ Division of Forestry and Wildlife.

Now that managers here know the insect’s home range, they can search for its natural enemies and test whether any of them can be used as biocontrol agents.

The thrips were found to be attacking naio (Myoporum sandwicense) at Waikoloa in March 2009, and the infestation has since spread to other areas in the northwestern part of the Big Island.

“What we’re seeing in the field, it’s pretty bad,” King told the Natural Area Reserve System Commission in June. She added that a grant application has been filed to fund biocontrol research.

Volume 22, Number 2 — August 2011