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fountaingrass Pennisetum setaceum

Fountaingrass (Pennisetum setaceum) is a major fire hazard on the Big Island and threatens native dryland forests there.

Photos by J.B. Friday, James Leary

Weed Control Information for Conservation

CTAHR PublicationsDr. James Leary

Herbicides and Native Plants

HBT: Herbicide Ballistic Technology (video): Dr. James Leary, CTAHR Invasive Weed Specialist, introduces Herbicide Ballistic Technology (HBT) to control invasive weeds in Hawaii. HBT provides accurate, long range directed herbicide applications for hard to reach incipient weed populations. Includes trials on banana poka (Passiflora tarminiana) and Australian tree fern (Sphaeropteris cooperi).

HBT Research Trials for Controlling Invasive Trees (video): Dr. James Leary, UH-CTAHR Invasive Weed Specialist, works with Jane Beachy, O'ahu Army National Resource Program at the Kahuku Training area, on HBT (herbicide ballistic technology) trials. Includes footage and descriptions of imazapyr (Habitat©) trials on silk oak (Grevillea robusta), octopus tree (Schefflera actinophylla), Christmas berry (Schinus terebinthifolius) and shoebutton ardisia (Ardisia elliptica).

HBT for Control of Photinia (video): Dr. James Leary, UH-CTAHR Invasive Weed Specialist, conducts HBT (herbicide ballistic technology) trials on Photinia davidiana with imazapyr (Habitat©). Includes footage showing herbicide damage to photinia and minimal damage to adjacent ohia and Acacia koa.

Koa Regeneration: Hands-free Spraying for Koa Corridors (video): Dr. James Leary, UH-CTAHR, conducts herbicide trials at Hakalau Forest National Wildlife Refuge to help re-establish critical habitat with Acacia koa vegetative corridors. Leary demonstrates the use of a prototype hands-free backpack sprayer to safely apply herbicide in uneven terrain.

Grass Suppression for Koa Regeneration (video): Dr. James Leary, UH-CTAHR, conducts herbicide trials at the Kona Hema Reserve to control grasses suppressing regrowth of koa seedlings (Acacia koa) using glyphosate (Roundup©), fluazifop-p-butyl (Fusilade©), and imazapyr (Habitat©). Dr. Leary also demonstrated use of a hands-free spraying system and evaluates the impacts of imazapyr on other native species (‘ohia, Metrosideros polymorpha).

Herbicide Trials at Volcano National Park (video): Dr. James Leary, UH-CTAHR, conducts herbicide field trials at the Volcano National Park to control grasses suppressing regrowth of koa seedlings (Acacia koa) using glyphosate (Roundup©), fluazifop-p-butyl (Fusilade©), and imazapyr (Habitat©). Two types of hands-free spraying systems are shown.

The Response of Native Hawaiian Grasses to Sequential Application of Pre and Postemergence Herbicides. Two experiments: One to determine the response of emoloa and pili grass to 4 preemergence herbicides applied twice to transplants and the other to determine the response of both grasses to two postemergence herbicides alone and in combination. Dr. Joseph DeFrank

The Response of Three Native Hawaiian Grasses to Two Sequential Applications of Selective Postemergence Grass Herbicides. Three native Hawaiian grasses are treated with 4 selective postemergence grass herbicides 2 times to determine sensitivity. Dr. Joseph DeFrank

The Response of Two Native Hawaiian Broadleaf Plants to Two sequential Applications of Preemergence Herbicides. Transplants of two native Hawaiian broad leaf plants are sprayed 2 times with 4 preemergence herbicides. Dr. Joseph DeFrank

Pre- and Post-emergent Herbicides on Two and Four Week Old Emoloa (Eragrostis variabilis) Seedlings Grown in Greenhose Trays Outdoors. Outdoor tray study to determine the response of 2 and 4 week old seedlings of emoloa to spray applications of both pre and postemergence herbicides. Dr. Joseph DeFrank

Evaluation of Herbicide Spray Applications to Seedling Emoloa. Direct seeded field grown emoloa seedlings are treated with both pre and postemergence herbicides applied with a 20 foot tractor mounted sprayer. Seedlings are 14 and 42 days old when treated. Treatments are similar to those found in tray study, see above. Dr. Joseph DeFrank