USDA approves fireweed control


Tribune-Herald staff writer

U.S. Sen. Daniel Inouye announced Wednesday that the U.S. Department of Agriculture has approved a biocontrol project aimed at slowing the spread of fireweed, or Madagascar ragwort, on the islands of Hawaii and Maui.

Fireweed is a noxious, invasive species that has infected an estimated 850,000 acres on the two islands, more than 20 percent of the state’s agricultural pasture lands.

The weed has no natural predators in Hawaii and is resistant to drought which allows it to spread rapidly, and it is expected to spread to an additional 1.5 million acres in the next 10 years if left unchecked.

Agriculture officials plan to release a species of moth next month on the two islands. The moths, which, like fireweed, are native to Madagascar, have been studied under quarantine in Hawaii since 1999. They are known to feed on fireweed, which is toxic to livestock.

Tim Richards, president of Kahua Ranch and past president of the Hawaii Cattleman’s Council, said the news of the approval is huge for Hawaii, “and that’s an understatement.”

For the past 10 years, the cattle ranchers have been losing the battle against fireweed, using chemicals and mechanical means in an attempt to control it. But due to the immense size of the infestation, “those methods are not feasible or economical,” Inouye said.

“It’s an ongoing ecological wreck,” Richards said, spreading up from the coast into the rain forests. “Because of the drought it grows quickly.”

KIA‘I MOKU: Fireweed has gotten a foothold – The Maui News


Even the largest wildfires start small. The 1988 Yellowstone fire started with a single lightning strike. The 2002 fires in Colorado and Utah started from burning love letters.

The blaze now burning on Maui and the fire on the Kohala Coast of Hawaii island both started with a single spark in the early 1980s.

What fire, you ask? Fireweed is burning across the hills of Upcountry Maui, and pastures are ablaze with little yellow flames. Fireweed, or Senecio madagascarensis, is a small shrubby plant from South Africa with a reputation for spreading like wildfire.

On Maui, the yellow daisylike flowers carpet the pastures around Makawao and Kula, creeping south into Ulupalakua and Kanaio. A survey of alien-plant populations along Maui roadsides done in 2000 and repeated in 2009 shows an explosion of fireweed. Forest and Kim Starr, who conducted the surveys, say fireweed has spread faster than any other alien-plant species they monitored and now covers tens of thousands of Maui acres.

Herbicide Field Day on Wedelia & Sedges

Reminder…Herbicide Field Day on Wedelia & Sedges

This Friday, April 4, 2008

To: Landscape & Golf Course Industries

Wedelia is often used as a groundcover. However, some people consider it a weed and efforts are currently being taken to place it on the invasive weed list. Recently an herbicide trial was conducted with Sedge-Hammer (SledgeHammer | Sledge-Hammer), Manage, Certainty, Monument, and Image for the control of wedelia, purple nutsedge, green kyllinga, and white kyllinga. You are invited to attend a field day to observe the herbicide effects on wedelia and the early results on these sedges.

Date: April 4, 2008 (Friday)
Place: Meet at Maui Community College Greenhouse, Kahului
Time: 11:00 to 12:00 pm
Registration Deadline April 3.

To register you may call the Cooperative Extension Service at 244-3242 x222 or x230.
Please notify us if you require special assistance or if you need directions to attend this event.

Educational Credits

  • One (1) pesticide credit from the Hawaii Dept. of Agriculture will be provided for categories 3 (Ornamental & Turf) and 10 (Demonstration, Research & Instruction).
  • Golf Course Superintendents Association of America educational credits will also be awarded.
  • One (1) UH/CES Landscape Advisor IPM credits will be provided.

This project is supported in part by the County of Maui.

Norman M. Nagata
Extension Agent (Landscape, Turfgrass, Ornamental Plant)
University of Hawaii at Manoa, Cooperative Extension Service
310 Kaahumanu Avenue, Bld. 214; Kahului, Maui, Hawaii 96732
Tele. (808)244-3242 x 230, Fax (808)244-7089