3rd International Conference on Parthenium

Prof N Irabanta Singh *

The author recently attended the 3rd International Conference on Parthenium (8-10 December, 2010) being organized by Indian Agricultural Research Institute, New Delhi & supported by Entomological Society of India. About 100 scientists representing USA, Australia, Israel, Pakistan and India attended the three-day deliberations.

The scientific presentation on Parthenium consists of five key note addresses and five thematic presentations viz.,

• Theme –1 (Global view of Parthenium in different countries and its threat to biodiversity);
• Theme -2 (Management strategies of Parthenium and other invasive weeds);
• Theme -3 (Diagnosis and management of Parthenium linked diseases in human beings);
• Theme – 4 (Utility aspects of Parthenium – medical, compost, pesticidal property, etc.);
• Theme 5 (Interface with farmers, patients, NGO’s and scientists to develop an International working group on Parthenium).

The abstract volume consists of 103 papers.

Parthenim hysterophorus L. (Helianthicae: Asteraceae) is a fast growing alien annual weed, native of South and Central America. In India, the weed was reported from Pune (Rao, 1956). It grows luxuriantly all throughout the year suppressing native vegetation thereby threatening the natural diversity and causes serious health hazards to human beings such as contact dermatitis, eczema, allergic reaction and live stock etc.

The present author presented an invited lecture on Parthenium invasion along with the railway tracts and road sides of National and State highways in North East India.

Systematic surveys made in three different National Highways, i.e., NH-39, NH-53 and NH-150 and two State Highways of Manipur as well as surveys made in other NE States viz.,
Nagaland (Kohima, NH-39),
Assam (Jorhat, NH-37;
Golaghat, NH-59;
Tezpur, NH-62;
Golpara, NH-33;
Bongaigaon, NH-31) and
Meghalaya (Shillong, NH-32)
revealed that Parthenium has now widespread in the NE India.

The three day deliberations can be summarized as -

Ill effects of Parthenium

Human: According to the scientists Parthenium contact dermatitis and allergic manifestation in school children form the largest number of airborne contact dermatitis in India and elsewhere. Airborne Parthenium pollen grains are in abundance during June to August.

Livestock – According to scientists, though cattle do not eat Parthenium, it effects were observed on them when they walk by or graze through patches of this weed. Feeding the weed to buffalo and bull calves caused acute and chronic toxicity with ulcerations in mouth and digestive tract. Consumption of milk from livestock grazing around Parthenium invaded land is hazardous to health due to Parthenium.

Ill effects of Parthenium Pollen

Allergencity study of pollen by various scientists revealed 50 percent of the population developed asthma, 16-17 percent with Urticaria and rhinitis.

Management of Parthenium

The common agreement in adaptive research on management revealed that “Integrated Parthenium Weed Management (IPWM)” involving various methods and suggested the following five crucial steps:

(i) Maintenance of naturally occurring biodiversity - i.e., not to disturb the existing flora to the extent possible to avoid invasion of Parthenium,

(ii) In places where cleaning and exposure of soil is unavoidable, planting of proven plants at the start of rainy season is effective. The growth of such plants will insulate soils from invasion by Parthenium. In already infested areas, planting of Botanical Agents (BAs) may be taken up at the start of rainy season.

Parthenium plants that are growing along with antagonistic plants need to be uprooted in the first one or two years so that the latter can establish well and discourage the growth of Parthenium. The BAs may differ from situation to situation in their allopathic impact which has to be researched and only the eco-friendly and effective ones are to be identified in as many numbers as possible for each situation.

In Karnataka State (India) and neighbourhood, the successful ones are,
Cassia sericea;
C. tora;
C. occidentalis;
C. auriculata;
Hyptis suaveolens;
Tephrosia purpurea;
Styloxanthus scabra;
Amaranthus spinosus;
Croton sparciflorus;
Sida spinosa;
Tagetus erecta;
Kochia indica;
Mirabilis Jalapa.

(ii) The Mexican beetle, Zygogramma bicolorata, a specific defoliator of Parthenium imported from Mexico, are to be released at the commencement of rains.

(iv) In other situations such as gardens, flowers beds, lawns, intensively cultivated, manual removal is a better option. Only those who are not allergic to Parthenium should uproot the weed.

(v) In certain other situations where Parthenium has densely invaded vast stretches of land and immediate relief is needed, chemical herbicides may be sprayed although it does not provide permanent control. As chemical sprays cause environmental pollution, they are recommended only as a last resort to suppress the weed in emergent situations.

The last two methods can also be integrated initially with biological methods for faster impact. This conference is very informative. It gives us knowledge how we will manage Parthenium for the welfare of human beings, livestocks and air pollution due to Parthenium pollen grains.

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* Prof N Irabanta Singh wrote this article for The Sangai Express
This article was webcasted on December 29, 2010.

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