The Problem of Eupatorium odoratum L. in Nigeria

Abstract

Oxford OX5 lPF, UK. Summary. A project was set up by the Nigerian government to study the ecology and biology of Eupatoriurn odoraturn and the possibility of biological control. Results of experiments with Gmelina arborea showed that E. odoraturn has very little effect on the establishment of Gmelina. Further experiments to test the interactions of Terminalis superba and lmperata cylindrica with E. odoraturn are being carried out. Work on seed biology shows that there seems to be l i t t l e seed dormancy and the seed does not survive in the soil for long. Soil conditions play an important part in E. odoratum establishment, seedlings growing more readily in sandy than in clay-loam soil. Latvae of the moth Arnmalo insdata Walk. provide the best possibility for biological control. Trials with the seed-eating beetle &ion brunneonigrurn B.B. are still in progress.Applications of either 2.4.5-T or 2.4-D a t 2 kg/ha killed only smaller plants.A mixture of 0.4 kg picloram and 1.6 kg 2.4-0 aminelha was very effective. Further experiments showed that a total dose of this mixture of only 1.0 kglha was still effective. Picloram, however, persisted in the soil for seven months when applied a t 2 kglha. Whilst 2.4-D is less persistant, the stage of weed growth a t which it is applied is far more critical and more trouble can be expected from subsequent seedling regrowth. Altrazine and diuron applied as foliage sprays at 5 kglha were effective.

Phytogeography and Invasion Spread of Chromolaena odorata (L.) R.M. King et H. Rob. in the Western Himalaya, India

“…In another study by Sahid & Sugau (1993) it was found that high allelopathic properties of this weed supported in gaining dominance in vegetation, and in replacing other aggressive invaders such as Lantana ca ma ra and Imperata cylindrica (L.) Beauv. of Poaceae, this was well supported by the findings of Eussen & de Groot (1974) and Ivens (1974) in Asia and Africa. The present stu dy shows that C. odorata forms extensive infestation in slightly moist frost free areas but it has started registering its presence in warm places also and will become invasive in medium to arid land use types that are not water stressed du ring summer season this is in line with the findings of Goodall & Erasmus (1996).…”

Use of Siam weed biomarker in assessing heavy metal contaminations in traffic and solid waste polluted areas

“…The plant is originated from the Caribbean, but has invasive population in Asia, southern and western Africa (Cruttwell McFadyen and Skarrat, 1996). It was accidentally introduced with forestry seed in Nigeria in 1947 (Ivens, 1974). It is a very resilient plant that survives cases of fire, drought or mechanical damage through coppicing because of an underground organ it possessed thereby tolerating a variety of climates (Gautier, 1993).…”

Invasion establishment and habitat suitability of Chromolaena odorata (L.) King and Robinson over time and space in the western Himalayan forests of India

“…In another study, the high allelopathic properties of this weed (Sahid and Sugau, 1993) support its gaining dominance in vegetation and in replacing other aggressive invaders such as Lantana camara L. (Verbenaceae) and Imperata cylindrica (L.) Beauv. of Poaceae (Eussen and de Groot, 1974;Ivens, 1974) in Asia and Africa. The present study shows that C. odorata forms extensive infestation in slightly moist frost-free areas, but it has also started appearing in warm places and will become invasive in medium to arid land use types that are not water stressed during summer season; this is in line with the findings of Goodall and Erasmus (1996).…”