Assessment of phytotoxic action of Ageratum conyzoides L. (billy goat weed) on weeds

Xuan, Tran Dang; Tawata, Shinkichi; Hong, Nguyen Huu; Khanh, Tran Dang; Min, Chung Ill

doi:10.1016/j.cropro.2004.02.005

Cited by 81 publications

(61 citation statements)

References 11 publications

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“…Some reports indicate that the weed exhibits allelopathic effects and affects the growth of arable crops like wheat, rice and chickpea and it was attributed to the presence of phenolics (Singh et al 2003;Batish et al 2006aBatish et al , 2008. A number of putative allelochemicals, both volatile and non-volatile, have been identified from the fresh leaves and aerial parts of the weed (Kong et al 2004;Xuan et al 2004;Batish et al 2008). However, the studies exploring the allelopathic interference of leaf debris of A. conyzoides that falls in large amount onto the ground and upon degradation gradually mixes with the soil, are lacking.…”

Section: Introductionmentioning

confidence: 97%

Nature of interference potential of leaf debris of Ageratum conyzoides

et al. 2008

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The present study investigated the allelopathic interference of leaf debris of Ageratum conyzoides (billy goat weed; Asteraceae)-a weed of cultivated land-against rice (Oryza sativa). Seedling length and dry weight of rice were significantly reduced (16-20%) in soil from A. conyzoides infested fields compared to the soil from an area devoid of the weed. It indicated the presence of certain phytotoxins in the A. conyzoides infested soil. To explore the possible contribution of the weed in releasing these phytotoxins, growth studies involving leaf debris extracts and amended soils (prepared by incorporating leaf debris-5, 10, 20 g kg -1 soil, w/w, or its extracts-0.5%, 1.0% and 2.0%, v/v) were conducted. The growth of rice was severely inhibited in A. conyzoides leaf debris-and debris extractamended soils compared to unamended control soil. A significant amount of water-soluble phenolics, the potent phytotoxins, was found in the A. conyzoides infested soil, leaf debris, and debris-amended soils. These phenolics were identified as gallic acid, coumalic acid, protocatechuic acid, catechin and p-hydroxybenzoic acid. Among these, protocatechuic acid was in the maximum amount (35.72%) followed by coumalic acid (33.49%) and these two accounted for[69% of total phenolic compounds. Further, there was a significant increase in the available nutrient content in soil amended with A. conyzoides leaf debris thus ruling out the possibility of any resource depletion upon residue incorporation and their negative role in causing growth reduction. Based on the observations, the present study concludes that leaf debris of A. conyzoides deleteriously affects the early growth of rice by releasing water-soluble phenolic acids into the soil environment and not through soil nutrient depletion.

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Section: Introductionmentioning

confidence: 97%

Nature of interference potential of leaf debris of Ageratum conyzoides

et al. 2008

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“…Ambika et al (2003);Hart et al (1976);Kohli and Rani (1994);Kong et al (2002);Okunade (2002);Saleh (1974);Vidya (1994);Xuan et al (2004).…”

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confidence: 96%

Status, invasiveness and environmental threats of three tropical American invasive weeds (Parthenium hysterophorus L., Ageratum conyzoides L., Lantana camara L.) in India

et al. 2006

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Invasive weeds have threatened the integrity of ecosystems throughout the world. They affect not only the species diversity of native areas but also their biological integrity. In India, a number of invasive exotic weeds have been reported but some viz. Parthenium hysterophorus, Lantana camara and Ageratum conyzoides, especially those from tropical America are troublesome and have caused adverse ecological, economic and social impact. These weeds can be seen growing in different landscapes but are luxuriantly localized in unattended forests and cultivated areas. Parthenium hysterophorus (Asteraceae, commonly known as congress grass) is perhaps the most troublesome and noxious weed of urban and rural India. Besides rapidly colonizing areas replacing the native vegetation, it is also known to cause a number of human health problems such as skin allergy, rhinitis and irritation to eyes of the residents in the vicinity. Likewise, it causes fodder scarcity in addition to being unpalatable and toxic to livestock. Lantana camara (Verbenaceae), another serious tropical American pest, has encroached upon large areas of land, especially the forests where it has virtually replaced the forest floor vegetation and reduced tree growth. Also because of its bushy and spreading type of growth it obstructs forest operations. The third weed, Ageratum conyzoides (Asteraceae, Billy goat weed) has invaded agricultural fields. It interferes with crops and causes yield reductions of major staple crops of India. When it invades rangeland areas, it out competes native grasses causing scarcity of fodder. These weeds have similar growth strategies such as fast growth rates, short life-cycles, greater reproductive potential, high competitive abilities and allelopathy that make them successful invaders of native habitats. Mechanical, chemical, biological and cultural control tactics have failed individually, though integrated approaches combining all these approaches along with community participation and proper land management have been relatively successful. This paper presents various aspects of biology, ecology, hazards and control measures of these weeds.

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“…Other compounds such as tannins have also been detected [9,10]. However, the toxicity, including hepatotoxicity, of this plant has not been extensively studied [4,11].…”

Section: Introductionmentioning

confidence: 99%