Parthenium hysterophorus L. – A NOXIOUS ALIEN WEED

 

Arshad Javaid[1] and Tehmina Anjum

 

ABSTRACT

 

 

 

 

 

 

 

 

 

Key words: Parthenium, distribution, Pakistan, Punjab, allepathy

 

INTRODUCTION

Parthenium hysterophorus L. is an upright annual herb of 30-150 cm of family Asteraceae. It is native to subtropics of North and South America (Adkins et al., 1996) and was accidentally introduced in subcontinent in 1955 through imported food grains. The weed has been rapidly spread in last twenty years and now it occurs widely along the roadsides, wastelands and sometimes in crop fields. The high dominance of Parthenium is attributed to its fast growth rate, high reproductive potential, adaptive nature and interference by allelopathy (Kohli and Rani, 1994).  P. hysterophorus establishes only from seeds, which can germinate anytime of year given suiTable-moisture levels. Plants flower when they are 4-8 weeks old and may flower for several months (Dhawan and Dhawan, 1996). An individual plant may produce 15,000-25,000 seeds (Navie et al., 1996). The weed lacks natural enemies in Pakistan. 

P. hysterophorus posses a serious health risk. The chemical analysis has indicated that all the plant parts including trichomes and pollens contain toxins called sesquiterpene lactones. The major components of toxin being ‘Parthenin’ and other phenolic acids such as caffeic acid, vanillic acid, anisic acid, chlorogenic acid and parahydroxy benzoic acid are lethal to human beings and animals (Oudhia, 1998). In addition to health hazards a lot of available data also highlights its impact on agriculture as well as natural ecosystems (Chippendale and Panetta, 1994; Evans, 1997). The weed is rapidly spreading in Pakistan. The present study reports the distribution of P. hysterophorus in wastelands and agricultural fields, effect of allelopathic grasses on distribution of P. hysterophorus and grazing response of cattle towards P. hysterophorus.

MATERIALS AND METHODS

Surveys of different districts of the province Punjab were undertaken during the years 2003-2005 to study the distribution of P. hysterophorus. In the surveyed areas P. hysterophorus distribution was studied on wastelands, along the roadsides, and along the sides and inside of the fields of various agricultural crops. In order to study the impact of P. hysterophorus on the distribution of native weeds, data was collected from undisturbed localities along the side of BRB canal near Daska, district Sialkot using  1x1 m² quadrate.  Frequency and density of P. hysterophorus and other weed species was estimated by applying the following formulas:

                

Absolute frequency (AF) (%) =	Number of quadrates in which species occurs	X 100
	Total number of quadrates

 

Relative frequency (RF) (%) =	Absolute frequency value for a species	X 100
	Total absolute frequency values for all species

 

Absolute density  (AD)   =	Total number of individuals of a species in all quadrates
	Total number of quadrates

 

Relative density (RD) (%) =	Absolute density for a species	X 100
	Total absolute density for all species

 

           Effect of other weed species especially perennial grasses on distribution of this weed species was also studied. The liking of animals including cows, buffalos, sheep and goats to parthenium was studied by observing these animals grazing in the pastures.

RESULTS AND DISCUSSION

Distribution of P. hysterophorus in wastelands

A general survey revealed that Parthenium has established itself in rain-fed districts of the province Punjab viz. Sialkot, Gujranwala, Lahore, Kasur, Shekhupura, Gujrat, Jehlem, Rawalpindi/Islamabad. It is also spreading up hills from Islamabad towards Murree.  However, the districts of southern Punjab viz. Bahawalpur, Multan and Bahawalnagar were either free of Parthenium colonization or there was a little infestation of this weed.  Low rain fall and salinity could be the possible regions of low Parthenium colonization in these areas. The weed is also spreading in Kashmir.

Most of the wastelands were found colonized by P. hysterophorus. Data collected from various localities in district Sialkot reveals that this weed was dominating the local flora at these sites with highest absolute frequency (AF) of 80%. The rest of the weed species showed 10–60% frequency of occurrence. Achyranthes aspera, Carthamus oxycantha, Malvestrum coromandelianum and Cynodon dactylon were found more frequent with 40-50% AF, than rest of the weed species with 10-30% AF. The highest relative frequency (RF) of 18.6% was exhibited by P. hysterophorus followed by C. dactylon (13.9%), M. coromandelianum (11.6%), C. oxycantha (11.6%) and A. aspera (9.3%), respectively. The rest of the weed species exhibited less than 7 RF (Table-1).

The highest absolute density (AD) of 41 was exhibited by P. hysterophorus followed by C. dactylon (39), M. coromandelianum (11.8) and C. oxycantha (5.9). The rest of the weed species showed an AD of less than 5. The relative density (RD) of P. hysterophorus and other weed species also exhibited a pattern similar to that of AD (Table-1). The domination and rapid spread of P. hysterophorus in wastelands with gradual reduction of local flora could be attributed to its invasive capacity, allelopathic properties, high growth rate, short growth cycle and large number of seed production (Srivastava et al., 1985; Evans, 1997; Oudhia, 1998). It has been reported as causing a total habitat change in native Australian grasslands, open woodlands, riverbanks and flood plains (McFadyen, 1992; Chippendale and Panetta, 1994). Similar invasions of Parthenium in National Wildlife Park in Southern India has also been reported (Evans, 1997). 

Effect of perennial allelopathic grasses on distribution of P. hysterophorus

            There was a very high infestation of P. hysterophorus in herb zone. The frequency and density of P. hysterophorus in this zone was 80 and 40, respectively. Both Desmostachya bipinnata and Imperata cylindrica colonization markedly reduced the distribution of this weed. The frequency and density of P. hysterophorus in D. bipinnata and I. cylindrica zone were reduced to 30 and 20, and 5 and 3, respectively (Figs. 1 & 2). This reduced frequency and density of P. hysterophorus in D. bipinnata and I. cylindrica dominating zones could be attributed to the release of water soluble allelochemicals released from roots and shoot of these grasses (Javaid et al., 2005; Anjum et al., 2005).

Invasion of P. hysterophorus in agricultural fields

            Heavy infestation of P. hysterophorus was found along the boundaries of the fields of agronomic and horticultural crops. However, P. hysterophorus was not found in the fields of economically important crops like rice, maize and wheat (Fig. 3). A careful observation over a period of one year revealed that the weed start to germinate in the fallow fields but later agricultural practices and crop competition generally eliminate it from the fields. It generally grows in field when crop is grown on ridges and furrows. It grows only on ridges. The weed can also grow in a field when a comparatively less competitive crop that does not cover the soil completely is sown as Citrullus vulgaris (Fig. 3D). Very few plants of P. hysterophorus were found growing in the fields of Trifolium alexandrinum only on the ridges. It seems probable that P. hysterophorus is unable to compete with most of the crops especially cereals. Furthermore, it is unable to cope with the agricultural practices and generally grows outside the agricultural fields. It is a common observation that P. hysterophorus does not grow on damp soils. Since it generally grows only on ridges in the fields, it is likely that irrigation schedule of the agricultural crops does not suit to P. hysterophorus. However, there are reports that this weed has become a problem in agricultural fields in India (Evans, 1997). It could be attributed to the difference in agricultural practices in the two countries. The failure of Parthenium to establish itself in our agricultural fields seems to be due to wetland rice cultivation.

Grazing response of cattle towards P. hysterophorus

            During surveys of various grazing pastures, it was found that cows, buffalos and sheep do not graze P.  hysterophorus while goats readily grazed it (Fig. 4). Similar findings have also been reported earlier from India (Narasimhan et al., 1977). However, earlier workers have reported that in artificial feeding tests cattle accepted the weed alone or in mixtures with green fodder, with severe consequences. The majority developed severe dermatitis and toxic symptoms and lesions were found subsequently in the gastrointestinal tract, liver and kidneys (Narasimhan et al., 1977). Changes in blood chemistry and inhibition of liver dehydrogenases, as well as degenerative changes in both the liver and kidneys, have been reported in buffalo and sheep (Ahmad et al., 1988; Rajkumar et al., 1988). The milk of cattle may also be tainted by Parthenium (Towers and Rao, 1992).

Table-1. Frequency and density of P. hysterophorus and other weeds in district Sialkot, Pakistan.