Dr. Banarsi Lal
Every year 16-22nd of August is celebrated as the Parthenium Awareness Week across India by the agricultural institutions across the nation. This week is celebrated by organising various awareness-cum-training programmes, campaigns, rallies, debates, essay competitions etc. by the various agricultural institutions. Through this programme people are guided how to eradicate this weed by manual, biological and chemical practices. Various posters, folders, books, video films etc. on Parthenium management are also provided to the stakeholders. Parthenium hysterophorus is commonly known as congress grass or carrot weed. It is also called as gajar ghas, ragweed, white cap or top, gajari, chatak candani, nakshtra gida, safed topi etc. It is most commonly called as ‘gajar ghas’ as it appears like carrot plant. It is herbaceous, an annual plant belonging to subfamily Heliantheae and family Asteraceae (Compositae).This weed has attained the status of “Worst Weed” It is a deadly weed infesting cropped and non-cropped areas. It has been observed that its infestation causes yield losses up to 40 per cent in several crops and reduces forage production up to 90 per cent. It is an aggressive annual herbaceous plant which has been widely dispersed in both the tropical and sub-tropical areas. This weed rapidly covers the new surroundings and poses a serious threat to our environment and biodiversity. This weed has been rapidly spreading from the last two decades. Parthenium weed has been categorised as “Cosmopolitan weed”, “National culprit” and “National health hazard” due to its serious environmental threats. Earlier it was considered as a weed of wasteland but now it has invaded almost every crop. Initially it was considered a problem in the crops of rain fed areas only but with the increase in irrigation facility, it germinates throughout the season. Parthenium causes inhibition of nodulation in legumes. Pulses have little impact in terms of smothering effect on parthenium as the crops are slow growing and short statured in nature.
Union Territory of Jammu And Kashmir is northernmost territory of India and its major part is situated in the Himalayan Mountains. It is also considered as the heaven on the Earth. J&K is blessed with immense natural beauty and most of its land is under orchards, pastures, grasslands, forests and wasteland ecosystems. As most of these lands are not used for frequent cultivation, the obnoxious weed like Parthenium hysterophorus (Congress grass) has invaded most of these areas. This is regarded as the worst weed because of its invasiveness, potential for spread and economic and environmental hazards. It is noxious because it is highly adaptable to almost all types of environmental conditions and can invade all types of lands, causes high losses in the yield of crops. This weed forms dense, impenetrable thickets and reduces the productivity of crops, pastures, orchards and forestry plantations by its competition for resources and allelopathic effects. The low productivity of these ecosystems lead to scarcity of food, fuel wood, fodder, fruits, monkey menace and migration of rural people to urban areas in search of jobs after leaving the land fallow. However, the majority of people of J&K depend upon their subsistence needs on such cultivated, uncultivated and degraded lands. Productivity of such lands can be restored by managing this obnoxious weed with the available technologies. I have made some efforts to discuss the biology of this obnoxious weed, its ecological impacts and management techniques. This troublesome weed has high rate of dispersal and adaptation to adverse conditions. Consequently, this weed has led to shrinkage of grazing area for animals, reduction in productivity crops and grasslands, threat to plant biodiversity, reduced growth of newly planted trees in manmade forests and interference in succession of natural forests which act as hiding place for wild animals and threat to ecology of J&K. This weed is now spreading rapidly its tentacles in agricultural lands, forests and pastures. It is spreading at an alarming rate in J&K and is found in almost all the districts of J&K. This weed is inversely affecting the biodiversity and ecological system of J&K. Parthenium origin is considered to be Mexico. In India, its occurrence was first noticed in Pune (Maharashtra) in 1955 and now it has spread throughout India. It is supposed to be introduced in India from the United States of America along with wheat and other cereals import. By 1972, it dispersed into the majority of the western states from Kashmir in the North to Kerala in the South. It has widely spread in India from Kargil region of Jammu and Kashmir to Port Blair in Andeman and Nicobar. It is said that it was introduced in Jammu and Kashmir in 1963 from Madhopur in Punjab across the Ravi River all along the national highway. After that it has been spread all over Jammu and Kashmir. Presently its infestation is alarming as it has covered large area in the state. It has been observed that this weed has reduced crop yields and has also affected biodiversity in J&K. It can be seen on roadside, railway tracts, vacant lands, wastelands, agricultural, horticultural and plantation crops, industrial areas, irrigation canals etc.Presently it is considered as one of the most problematic weed. Its invasion in India has been estimated to be about 35 million hectares. It has wide adaptability to climate and soil conditions. It grows luxuriantly and does not allow any other vegetation nearby or underneath. It grows even in the Central Himalayan Mountains at an elevation of about 2000m above MSL. It has also been found to occupy large area of pasture land and hence reducing the fodder availability to animals. The average height of parthenium plant is 60cm-1.5m and the average plant population is 112-828 per square meter. It is deep-rooted ,much branched and dicotyledonous weed plant. A single healthy plant can produce about 15000-25000 seeds.
Parthenium causes health problems in humans and animals. It has been observed that any part of the plant (even root) can cause the subsequent risk of allergic reactions. In humans it causes health hazards like skin allergy (dermatitis), hay fever, asthma and bronchitis with flowers, seeds and even hair on leaves. Allergic papules are observed in school boys when they volunteered for uprooting parthenium. Animals are equally prone to the harmful effect of the weed. In dry season, when the animals do not get palatable species in grazing lands, they are forced to feed on parthenium. As a result milk taste becomes bitter and they suffer with ulcers in mouth and intestine. Whenever animals walk or graze through parthenium, their udders are inflamed and they suffer with fever and rashes. Histopathology of the kidney and liver revealed degenerative changes and necrosis. The milk consumption of the animals grazing around parthenium invaded fields is hazardous to man. Some animals feeding on parthenium are died due to acute dysentery, itching, cryhematous, development of oedema around eyelids, dorsum of tongue, loss of hair etc. Parthenin is the chief chemical (0.3%) found in the weed.
The manual removal is effective if adapted before flowering. Uprooting the weed manually when the soil is wet and slashing with word, collecting and burning the weed before flowering are some of the means its manual control. Community efforts involving all sections of the society are needed to manage the parthenium. The spraying of a solution of common salt (Sodium Chloride) at 15-20 per cent concentration has been found very effective. Applications of herbicides like glyphosate (1-1.5%) for total vegetation control or metribuzin (0.3-0.5%) if grasses are to be saved in non-agricultural land are considered effective in preventing this weed spread. It can also be controlled by the use of bio agent Mexican beetle (Zygogramma bicolorata) as it is natural, self sustaining, inexpensive and is ideally suited to non-crop situations and wastelands. This bio agent remains most active during rainy season and it completely controls the weed. The plant species like Cassia tara, Cassia seriea, Amaranthus asper, Malva pustulata etc. have capability to replace parthenium. The other way to manage parthenium by uprooting it before flowering and make compost by pit method. It can also be used for vermicomposting. Farmers can make good quality compost as it does not need special equipments and infrastructure. It can also be used in papermaking, an antifeedant and phagostimulants. National Research Centre for Weed Science, Jabalpur (M.P.) organises many awareness programmes throughout the country by involving Krishi Vigyan Kendras, institutes under ICAR, environmental agencies, NGOs, schools etc. Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu (SKUAST-J) also organises such programmes and feedback from the stakeholders proved that people are really interested to curb this menace. SKUAST-Jammu also organises the awareness week on parthenium management from 16-22nd of August. Krishi Vigyan Kendras of SKUAST-J campaigns at different places of Jammu province including schools and motivate the people to eradicate this weed. People from all sections of society should actively participate to curb this obnoxious weed.
(The writer is Sr. Scientist & Head of KVK, Reasi SKUAST-J).
