Agricultural Reviews

Mikania micrantha is an economically damaging invasive weed, which is widely naturalized in the tropical and subtropical regions of the world. This weed has reported yield losses in various cash crops and plantation crops in South East Asia including India. M. micrantha was found to change the soil microbial communities (bacteria, fungi and actinomycetes) as well as the soil chemical properties. It enhances a significant increase in aerobic bacteria but decreases in anaerobic bacteria due to which infested soil were free from other weeds. Similarly, in soil chemical characteristics significant increases in pH, total N and P were observed and a decrease in soil organic matter where M. micrantha is prevalent. It has allelopathic properties which affect neighbouring crops, weeds, insects and pathogens. This weed produces allelochemicals (phenolics, flavonoids, alkaloids and terpenes) that may be released by volatilization and decomposition of plant debris. It was also found that the aqueous leaf extract of invasive weed M. micrantha inhibited seed germination and seedling growth of various cereals, vegetables, and other plants. A similar result was found in test crops but there was no affected case found in the greenhouse experiment. This review will help the researchers and scientists in understanding the harmful effect of this invasive weed.