Bio-herbicide potential of naturalised Desmodium uncinatum crude leaf extract against the invasive plant species Parthenium hysterophorus

Abstract

The exotic plant Parthenium hysterophorus is rapidly invading ecosystems in sub-Saharan Africa, with negative effects on the environment, economy and human and animal health. With the exception of some synthetic herbicides, none of the available management methods have been effective against P. hysterophorus, and carry risks to the environment. Therefore, additional management methods must be explored for an effective integrated approach. Despite the fact that bio-herbicides are considered cost-effective and eco-friendly in mitigating biological invasions, little work has been done to utilize them for controlling P. hysterophorus. We investigated allelopathic effects and, thus, bio-herbicide potential of naturalised Desmodium uncinatum leaf (DuL) crude extract in various concentrations to control P. hysterophorus. Our results revealed that DuL crude extract can suppress P. hysterophorus, particularly at higher concentrations. The 75% and 100% DuL crude extract concentrations reduced the total leaf chlorophyll content by 26% and 22% in pots and plots, respectively. Further, these higher concentrations inhibited P. hysterophorus seed germination by 73% in petri dishes, 60% in pots, and 57% in plots, and negatively interfered with seedling growth vigour. Seedling stem heights under 75% and 100% DuL concentrations in pot and plot experiments was about 30% and 36% shorter than those sprayed with lower concentrations (< 70%) and the control, respectively. We show that naturalised plants with allelochemicals can be used as a management tool for controlling P. hysterophorus infestations in sub-Saharan Africa, particularly in Tanzania, and this method should become part of an integrated control toolkit being deployed in a communitybased approach.

Plant competition as an ecosystem-based management tool for suppressing Parthenium hysterophorus in rangelands

“…Four young, fresh leaves from 10 P. hysterophorus individuals per plot were selected for analysis of total leaf chlorophyll content (i.e., total Chl). 31 The total Chl was measured as an index of P. hysterophorus seedling health in response to suppressive effects of the competitive plant(s). We used 70 mg of P. hysterophorus leaves immersed in 6 ml of dimethyl sulfoxide (DMSO) in a test-tube, and incubated at 65°C for 12 h. 32,33 Afterwards, the extract was diluted to a total volume of 10 ml with DMSO.…”

Determination of allelopathic properties of Acacia catechu (L.f.) Willd.

“…Therefore, it is crucial to find alternative ways to manage weeds that is sustainable and eco-friendly. The biological approach is considered a natural method of weed management in farming systems (Hunt et al, 2017;Xiao et al, 2017; AcademicPres Notulae Botanicae Horti Cluj-Napoca Agrobotanici Ojija et al, 2019). Biological approach of weed control is a method which integrates the use of various natural organisms and approaches like allelopathy, competition of crop, and different agronomic practices (Sodaeizadeh and Hosseini, 2012).…”

Invasion, Impact and Control Techniques for Invasive Ipomoea hildebrandtii on Maasai Steppe Rangelands

“…As invasive plants dominate on rangelands they modify vegetation structure by suppressing native species through allelopathy or competition for resources i.e. water, nutrients, space, pollinators and light [16][17][18][19]. Allelopathy has been defined as effect of a plant species on seeds germination, growth and development of nearby plants by the release of allelochemicals into the habitat [20].…”

“…Moreover, previous studies show that invasive plants exert negative effect on crop and livestock production [21], pollination [17,22,23] as well as human and animal health [10,24]. The magnitude of the problem is supposed to be augmented by the increase of invasions and spreading nature of invasive plant species [21].…”