Merremia spp.

April 2000. Merremia spp. are a problem in many countries of the Pacific; they can be a nuisance after logging or as an invasive weed. On Kauai a severe, but localized (several hundred acres in the Wainiha valley), infestation of the M. peltata (Convolvulaceae) was reported. the outbreak first occurred 25 years ago. The question was how to eradicate it before it spread more extensively.

Glyphosate appears to be a candidate pesticide for control of this weed (Miller F (1982) Evaluation of glyphosate for use against Meremia spp. in Solomon Islands. Tropical Pest Management 28: 347-354. The abstract provides the following information.

Trials have shown glyphosate to be an effective herbicide for use against Merremia spp., major weed problems in forestry plantation areas of the Solomon Islands. The herbicide’s cost, however, and the large size (10,000-13,000 ha) of areas requiring treatment are constraints which may limit its potential. The aim of these trials was to determine the minimum dosage that would give satisfactory control. Results indicate that 1.5 kg a.i./ha would be sufficient. A new method of objective assessment of growth is also described.

An alternative method reported from Daintree rain forests in North Queensland is to identify and cut the major stems. Regrowth is minimal.