Sir,
I have been reading that many residents have been complaining about the increasing menace of parthenium in parks, vacant sites, roadsides etc.(SOM dated June 19, 24, 25). There have been complaints of increased problems of mosquitoes, rats, rodents and snakes. They have been exhorting the MCC to take action in controlling this menace.
Parthenium is an alien invasive weed, supposed to have introduced into the country as a contaminant in wheat imports under the PL480 from USA in the early fifties. First recorded in Pune in 1955, the weed has spread like wildfire and has now taken over the entire country.
It is known to cause skin allergy and breathing problems is sensitive individuals. With its high seed production capacity and dissemination through wind and movement of vehicles and animals, the weed spreads fast and colonises the space by replacing the native flora. The livestock is therefore greatly affected by this as they are deprived of fodder.
The weed is not touched by the livestock (not even by goats) as they contain high phenolic compounds. It is not even attacked by any serious insect pests or pathogens. These are facilitating the unrestricted growth and spread of this invasive weed.
The weed is difficult to control. Uprooting of young plants before they flower is effective but is expensive as it needs to be done frequently. Many chemicals (herbicides) are available which are very effective against parthenium and are inexpensive. There are some which will kill only parthenium without affecting the grass. They are very safe if used judiciously. An introduced insect Zygogramma bicolorata (Mexican beetle) offers biological control of this weed. However, despite intense efforts by Indian Council of Agricultural Research (ICAR), the technology has been found to be of limited use. But it has its own advantages and can be one of the components in the overall long-term management of the weed.
There is a need for increased public awareness of the negative impact of the weed and its management strategies. It requires a collective effort by the community and the civic body. Selective and careful use of herbicides will be the cheapest and most-effective approach in managing this weed. I urge the MCC to treat this as a serious problem and initiate action to control the weed on a war-footing. I am willing to provide technical guidance, if required.
– N. T. Yaduraju, Former Director, ICAR-Directorate of Weed Research, Jabalpur, Mysuru 1.7.2017
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