Can we eradicate Congress grass from NE India?

Prof N Irabanta Singh *

Parthenium hysterophorus at Salem, Tamil Nadu :: Pix - Wikipedia/Thamizhpparithi Maari

Introduction

The problem of Congress grass (Parthenium hysterophorous L.) has been known to the public since last six decades as it affects human and animal health, disturbed biodiversity, changed environment. It is one of the dreaded terrestrial weed in India. Of late, it has become serious problem for the NE India also.

The plant can grow under harsh environment with unique ecological effect, human and animal health hazards, etc. Today, the general public need awareness of harmful effects of Parthenium.

Density and Infestation of Parthenium in NE India

The present writer and his associates recorded the highest density and infestation of Parthenium in NH-31 (Bongaigaon), NH-53 (Goalpara), NH-39 (Dimapur-Imphal Road), NH-52 (Tezpur), NH-150 (Imphal-Bishnupur Road). The spread and infestation level was medium in NH-40 (Guwahati), NH-59 (Goalpara) and NH-37 (Nagaon) while low spread was recorded in NH-62 (Rhi Bhoi district, Meghalaya State), NH-53 (Imphal-Jiri Road) and NH-44 (Agartala, Tripura) (Please refer to The Sangai Express, 30th June, 2012).

In term of density and infestation level of Parthenium in the North East India as compared to other states of India, it was moderate in Assam and low in Arunachal Pradesh, Manipur, Mizoram, Meghalaya, Nagaland and Sikkim (Irabanta Singh, 2012).

Management of Parthenium in NE India

An integrated approach involving physical-mechanical, chemical and biological methods can offer an effective control measure of Parthenium from the NE India.

Physical-mechanical method

Manual removal/uprooting of Parthenium could be carried out before flower bloom and fruit sets in particularly when the soil is wet to prevent further re-enforcement of its seed to the soil and dispersal to newer areas. But manual method is not practicable in vast areas with heavy infestation (Mahadevappa, 1999).

In limited situations the method can work that too by engaging persons insensitive to Parthenium allergy to uproot the plants. Even in such cases, with safety measures such as wearing hand gloves and nose covers are necessary. The relief expected from this method alone is only temporary and need to be repeated as and when the weed appears.

Moreover, mechanical control is time consuming and unpleasant job and made worse by the health hazards involved with handling Parthenium.

Chemical method

Herbicides are found effective against the control of Parthenium in cultivated and non-cultivated areas in various parts of India. The performance of metribuzin application at 1000 and 1500g/ha was superior to other herbicidal treatment (Sharma and Gautam, 2004) which resulted its 100 percent mortality within a week of its application. The herbicidal effect does not last long, it ends only in one generation. Moreover, chemicals are often too expensive for farmers to use and the value of amenity land makes their use prohibitive.

The available mechanical or chemical control measures are neither feasible nor economical.

Therefore, weed control using classical biological means is less expensive, pollution free. Hence, recommended for biological control method.

Biological control method

Here living things (allelopathic or competitive plants, insects, fungus, etc.,) are used to suppress the growth of Parthenium weed.

Through competitive plants

It can be achieved either by conservation of naturally occurring plant species or through deliberate use of known competitive plant species to suppress the growth of Parthenium.

Use of Sickle pod (Cassia tora L.)

As a competitive biological control measure, sickle pod (Cassia tora L.) can be recommended for replacement of Parthenium on the road side, community land and waste lands in the NE India (Please refer to The Sangai Express, 8th Nov. 2015 issue).

Through Mexican beetle (Zygogramma bicolorata)

Field release of Mexican beetle were initiated in NE India (Please refer to The Sangai Express. 12th Oct, 2015 issue). The present writer and his associates made serious effort to multiply large number of beetles in mosquito net as well as net house by sowing the seeds of Parthenium and subsequent planting of seedlings after defoliation by the beetles. Mass rearing of the beetles in agro-net house during summer and in polyhouses for winter are in progress. Mass release undertaken when sufficient amount of beetles are available.

Conclusion and suggestion

Integrated approaches including physical-mechanical, chemical and biological control methods have to be made at least 2 – 3 years for complete eradication of Parthenium in a locality. Further, every citizen also needs to take responsibility to eradicate the Parthenium plants establishing in their surrounding.

Also broadcasting of Cassia tora (Sickle pod) seeds in the Parthenium infested areas followed by the release of Mexican beetle (Z. bicolorata) could reduce the spread of Parthenium. If such approaches are made, Parthenium can be eradicated from the soils of NE India.