NEW INVASIVE PLANT IDENTIFIED ON SAIPAN

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By John Ravelo

SAIPAN, CNMI (Saipan Tribune, Jan. 16) - The Department of Lands and Natural Resources disclosed yesterday the presence of another invasive plant that threatens the islands' vegetation.

The DLNR estimated that the Mimosa invisa, a fast-growing thorny shrub, has infested approximately 200 hectares of land in the CNMI.

Although DLNR's Tim Thornberg said the infestation is still relatively small, the invasive plant continues to spread.

"We're catching it early, so we should be able to control it," Thornberg said.

The U.S. Forest Health Service has awarded a $50,000 competitive grant to the DLNR to control the spread of the giant sensitive plant, he said.

"The giant sensitive plant climbs over other plants and forms tangled thickets that smother useful plants. Its sharp thorns make it impenetrable and grazing animals avoid it. The giant sensitive plant is a recent introduction into Guam and is now present on Saipan as well," a DLNR media release stated.

Thornberg said the CNMI is planning to release a biocontrol agent to control the spread of the plant. The use of the insect, Heteropsylla spinulosa, has been used to combat the invasive plant in Australia, Fiji, Samoa, Pohnpei, Palau and Papua New Guinea.

In the media release, DLNR Secretary Tom Pangelinan disclosed that his agency is working with Dr. Rangaswamy Muniappan, a retired entomologist and a professor emeritus at the University of Guam, in securing the U.S. Department of Agriculture's approval of the release of the biocontrol agent.

Initially, however, Pangelinan said hand weeding is possible when the plant first appears; the thorns could cause painful sores, though.

CNMI Division of Agriculture Donald Flores said they considered several options to eradicate the invasive plant, which include the slash-and-burn method and the use of pesticides. While pesticide use is not desirable for economic and environmental reasons, Flores said the slash-and-burn method would also be ineffective because it could leave seeds in the soil and allow them to germinate.

The DLNR has yet to ascertain the status of a biocontrol agent-a beetle known as weevils-that was released sometime last year to control another invasive plant specie, the noxious ivy gourd. The DLNR released a total of 450 weevils sometime in May and July.

The proliferation of ivy gourd has also supported the population of melon flies, an agricultural pest that destroy several crops. Isidoro T. Cabrera, agricultural consultant to the Northern Marianas College's Cooperative Research, Extension & Education Service, recently said the melon fly population remains in the millions.

The U.S. Agricultural Service considers the melon fly as a major economic pest, which attacks agricultural crops such as squash, cucumber, melon, tomato, pumpkin, guava, papaya, cowpea, string bean, and bitter melon, among others. Cabrera said the flies also attack bitter gourd, cantaloupe, watermelon and mango. The insect lays its eggs inside these fruits

January 16, 2004

Saipan Tribune: http://www.tribune.co.mp/

 

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