KOHALA MOUNTAIN, Hawaii: A hungry caterpillar was released with fanfare last week on a wet and windy Kohala Mountain.
The Madagascan Fireweed Moth is the new weapon in the war against fireweed, a pretty but deadly plant with yellow daisy-like flowers, which has been spreading across Hawaii Island at an alarming rate.
The invasive plant is toxic to livestock, presenting a problem for the state’s prime pasturelands. It is estimated that the weed has infested more than 850,000 acres, mainly on Maui and Hawaii Island.
Dr. Tim Richards is the president of Kahua Ranch where the first moths were released. He says the ranchers are solidly behind the biocontrol effort.
It is believed that fireweed came to the islands in hydromulch material imported from Australia where it is a serious pest.
Besides Hawaii, fireweed has spread through many parts of the world killing animals in Australia, Brazil, Argentina, Colombia, Venezuela, Uruguay, and Japan. The moth is the first biocontrol agent to be released against Madagascar fireweed in the world.
It has taken more than 13 years to get to this point. Entomologists and researchers at the Hawaii Department of Agriculture literally searched the world for a natural enemy of the weed that would be safe to release in Hawaii.
Doing much of the legwork… exploratory entomologist, Dr. Mohsen Ramadan… who was present for the insect release on Kohala Mountain last week.
Ramadan traveled to Australia, South Africa and Madagascar in 1999 and returned with 14 insects and one fungus, all of which were researched and tested under quarantine conditions. Some were found to be ineffective, while others were found to harm other native or beneficial plants.
The most promising turned out to be the Madagascan Fireweed Moth, the larvae of which voraciously eats the leaves of fireweed.
The state approved the release of the moth two years ago, but the use of the insect also required a federal permit.
Now, with all approvals in place, the moths are being released, and officials are stepping up production of the insect, which they say is easy to rear.
These movable containers will also help the moth to proliferate in its new home.
It is believed that the moth will be only one aspect of the fireweed control.
The state ag department is also testing four other potential natural enemies of fireweed. Each one appears to attack different parts of the plant
Darcy Oishi is the section chief of the Ag Department’s Biocontrol Section.
There are also effective pesticides, but officials say its expensive and impractical to use them across hundreds and thousands of acres.
As we learned in September 2011, officials have big plans for biocontrol. The 13th annual Symposium on Biological Control of Weeds was held in Waikoloa, and state.
The philosophy of fighting one invasive species by introducing another has gotten a poor response from Hawaii’s residents in the past.
The community was sent into an uproar over a plan to release a scale insect to diminish the vigor of strawberry guava – also called waiawi.
The Hawaii County Council even passed a resolution resisting the plan to release the bug…
Nonetheless, the environmental assessments were approved.
Big Island Video news has learned that the scale insects have been quietly released, and that pending an initial review, another – more public – release will be planned like the one for fireweed at Kahua Ranch.
In light of the public resistance, state officials are quick to point out the successes they say they have had with biocontrol. Since 1975, the ag department says it has released 51 biocontrol agents and all have been successful. They say none have been found to attack anything but the target pest or weed.
The state also claims that the use of biocontrol has deep connections to Hawaiian culture. Ag officials say the Hawaiian Kingdom was a world leader in biocontrol with successful introductions of a beetle to control cottony cushion scale in 1890.
The state points to the more recent release of an insect to contain the spread of the stinging nettle caterpillar: A nasty creature that – unlike the fruitful strawberry guava plant – had no defenders on the island.
Big Island Video News documented the stinging nettle biocontrol release in June 2010, which was unopposed.
However, the public often points to the mongoose and the rat… the well known cautionary tale about the less scientific introduction to Hawaii of the mongoose in order to control rats in the days of the sugar plantations. The control was a failure, and the mongoose has proliferated to become a nuisance themselves.
The story of the mongoose and the rat makes modern day officials cringe. They say its unfair to compare it today’s tedious and careful process.
Meanwhile, Ramadan has continued his travels… looking for more potential biocontrols for fireweed and other pests, such as coffee berry borer, small hive beetle and the protea mealybug.