Made a difference … Diana Crow

Maui’s ranchers and farmers are waging war against the toxic fireweed that can kill livestock and consumes water and nutrients, cutting off the food supply from other plants.

Beginning in March, farmers and ranchers received more than 2,500 Madagascan fireweed moths and larvae that they had hoped would rid their pastures of the plant toxic to their animals if eaten. More larvae have been given out in past months.

Rather than just leaving the eradication efforts to the experts, farmers and ranchers have taken it upon themselves to help combat the non-native plant that has infested more than 400,000 acres of range land in the state. Most of the noxious plants are found on Maui and the Big Island.

“It’s the first time we have had this collaborative effort with the ranchers or the clients that are impacted. They have been great with working with us and driving it,” said Neil Reimer, plant pest control branch chief with the state Department of Agriculture, which is assisting the farmers and ranchers along with the University of Hawaii’s College of Tropical Agriculture and Human Resources.

A similar effort is underway on the Big Island.

While Reimer and the ranchers and farmers admit it’s still early to tell whether their efforts are working, they are committed to raising the moths that are described as “eating machines” when it comes to eating fireweed. The caterpillars eat everything green on the plant while leaving other plants alone.

Officials involved with the project said ranches and farmers who have taken the larvae and moths include Haleakala, Kaupo, Thompson, Ulupalakua, Diamond B and Niles-Perreira ranches, Maliko Estate Coffee, Anuhea Hog Farm, Naalae Beef, Santos Ranch and ZD Ranch along with Forest and Kim Starr.

Official lists could not be obtained from state agencies that cited privacy reasons. The Maui Cattlemen’s Association is also assisting in the program.

Diana Crow, a horticulturist with Ulupalakua Ranch, said approximately 1,000 caterpillars per month have been released from their rearing cages since May.

While, she too says its too early to say how the project is going, she has seen some bright spots.

Fireweed enclosed in field cages with the moth “looks ragged and sad and sometimes other desirable forage plants are able to out-compete the fireweed,” she said in an email.

Crow and fellow workers at Ulupalakua Ranch are seeing the moths around the ranch, even around their buildings.

Since there is no fireweed for the tiny hatchlings to feed on around the buildings, Crow takes a paintbrush and a cup to rescue them.

“At this early stage every single individual is important,” she said.

* Melissa Tanji can be reached at