Journal of Research in Weed Science

Abstract Since its introduction into Ethiopia during 1970s, Prosopis juliflora, became an environmental issue in areas where it was first introduced to combat desertification. This review paper was aimed at reviewing some adverse effects of the plant on socioeconomic, environmental and biodiversity with its control practices in the eastern Ethiopia. Contrary to its purpose of introduction, this plant has been found to be highly invasive and, it imposed adverse effects on the native plant species. The plant is declared as an invader which has put impacts on socioeconomic, environment, and biodiversity of the eastern region of Ethiopia especially afar region and Dire Dawa; which became alarm for pastoralists, development agents, scientists, and policy makers. Though cultural practices such as burning and cutting were mainly practiced, the invasion could not be stopped.

Abstract Water hyacinth is free-floating, stoloniferous and perennial herb. It is an aquatic invasive species; native to South America and most aggressive invasive species worldwide. It profoundly invaded the tropical and subtropical region of the world, as a result of ornamental properties and reproductive capability of the weed. In addition, it is recognized as one of the worst weeds due to its rapid proliferation rate, ecological adaptability and detrimental effects on environment, human health and economic development. It poses serious socio-economic and environmental problems includes destruction of biodiversity, hindrance to water transport and recreation, oxygen depletion and reduction of water quality, breeding ground for pests, vectors and their effect on human health, hampering agriculture and fisheries, affect hydropower and water supply systems and increased evapo-transpiration. Therefore deferent management strategies such as physical, chemical and biological methods had been used to control the weed. Accordingly manual removal was used in South Africa; Zimbabwe Lake Mutirikwi; Ethiopia Wonji-Shewa Sugar Factory and Owen fall hydropower in Jinja at Lake Victoria. Chemical control was practiced in Zimbabwe Lake Chivero using 2-4-D; South-west Nigeria Ere fishing channel by glyphosate; South Africa larger dams and river systems by using glyphosate; Zimbabwe acetic acid and glyphosate control the weed at experimental site. Biological control was practiced in Zimbabwe Lake Chivero through combination of weevil and fungi; Kenya Lake Victoria and China by two types of weevils (Neochetina bruchi and Neochetina eichhornia) and Ethiopia Neochetina bruchi and fungi at Rift Valley and in green house at experimental level respectively.

Abstract Availability of herbicides inflicts to adopt an integrated use of weed control methods (other than chemical methods) in minor crops. In Pakistan more than 70% farmers have land less than 5 ha, so it is improvident to employ very costly chemical and mechanical weed control methods. At present, the resource conservation technology is widely adopted, so it is a major challenge to develop a sustainable, reliable and integrated weed management system. As in minor crops, sustainable production contributes in agricultural production as well as food security and food supply; therefore, it is important for national economies and human health. Excessive use of herbicides over a long time make leads herbicide resistant weeds. There are some factors including shifting ability of weed population, increase in environmental concerns and increase in cost of management, all these factors made farmers difficult to control resistant weeds within their limited resources. It is proved from previous research that selection of viable seed and the use of different cultural practices maybe conceivable strategy to decrease weed competition. Our focus in this review article is on the utilization of these practices to reduce the competitive ability of weeds, for their proper management in minor crops. Our basic aim of this article is to assist researchers in the design of eco-friendly and economically viable weed management strategies, which will help in reducing the herbicides liability and mechanical cultivation from farmer’s production costs.

Abstract Weeds are ubiquitous and eternal pests. In India, the total annual loss of agricultural produce by weeds, insects, diseases and other pests are estimated to be 37%, 29%, 22% and 12%, respectively. Weeds are, mainly, autotrophs, but few are heterotrophs/parasitic such as Orobanche/ Phelipanche sp (Broomrape). Several species that are dominant across the world are Orobanche cernua, Orobanche crenata, Phelipanche ramosa, Phelipanche aegyptiaca, Orobanche cumana, and Phelipanche muteli. Orobanche is an important holo-root parasitic weed and cause yield losses of many economically important crops. The damage by Orobanche can range from 0-100%. Studies highlighted annual crop losses due to Orobanche infestation was to the tune of $1.3 to 2.6 billion worldwide.A Orobanche plant can produce more than 500,000 seeds, whose longevity may vary from 2-20 years. The distribution, species diversity and biology of this weed have been discussed in this review. Sound management strategies involving physical, cultural, biological and chemical options, and above all, integrated Orobanche management have been contemplated as well. New bio-technological approach that must trigger to develop host plant’s resistance against Orobanche and recommended selective herbicides should be envisaged for better Orobanche management.

Abstract The weeds are well accepted source of herbal medicines. However, these plants should be managed and removed from agro ecosystems due to their negative impacts on agricultural production systems. However, it is matter of interest that some of well-known weeds are source of drugs and traditional medicine. The weeds have certain biological phytochemicals viz. alkaloids, flavonoids, phenols, terpenes, and saponins etc. which are used to treat health disorders. The demand and importance of natural occurring herbal drugs is rising globally. This is due to their social contentment, easy accessibility, cheapness, effectiveness and no side effect claims. The use of herbs and weeds is based on empirical treatment and experiences from many generations with info accessible solely in native magazines. These medicines possess numerous biologically active ingredients associated with health disorders. Thus their potential has not been fully explored. There is need to improve the quality and analysis of herbal products to be fabricated with research advancements in their efficacy. This review identifies bioactive or phytochemicals present in different plant parts of weeds and ways to extract them are discussed. In addition, the medicinal beneficial aspects of weed species, their medicinal utility and major concerning issues are also highlighted.

Abstract Rice industry in Malaysia faces serious challenges in managing weedy rice (Oryza sativa L.) since it was first observed in 1988. Unfortunately, there is no simple control method for weedy rice. Recommended practices in Malaysia adopted various integrated weedy rice management strategies mainly on land preparation and pre-harvest period controls. Multiple tillage, chemical applications via pre-emergence and pre-sowing herbicide, and manual weeding are the usual weedy rice control practices by majority of Malaysian farmers. The conspecific nature of weedy rice with cultivated rice increased the difficulty to control the weed with several weedy rice biotypes have already mimic the local varieties. Introduction of Clearfield® Rice Production System (CPS) in 2010 has shifted the current weedy rice management strategies to an herbicide-tolerant crop approach. Some concerns of the technology including potential resistant to weedy rice and environmental issues were discussed. Additional weedy rice management strategies as alternative approaches for Malaysia rice agro-ecosystems were proposed in this review to fill the gaps on current weedy rice controls including reducing cross contamination between farms, managing weedy rice seedbank, empowering alternative culture methods in rice farming, strengthening current Clearfield® system, and exploring ‘omics’ research for other potential herbicide tolerant rice. Improvement in communication is proposed to ensure any information on weedy rice management is effectively transferred between farmers and authorities.

Abstract An inventory of cultural control practices is undertaken by considering each practice for its biological selectivity with respect to weeds. Descriptions of cultural practices in the literature are often brief. Some recent syntheses neglect knowledge from older publications. Disagreement concerning the delimitation of these practices is common. Clarification of the knowledge base concerning the cultural management of field flora is required for "sustainable agriculture". The selectivity most often mentioned for each practice is limited to a few examples of taxa in a geographically limited area and is rarely considered in the light of general mechanisms of action on biological cycles. The controversial distinction made by many authors between preventive and curative methods is unnecessary. Each practice listed is presented with its biological target. On the scale of a single cultural cycle, thirty practices are compared. Each target tends to have a specific biological descriptor. Most of the practice target pairs have the disadvantage of having an extreme state opposed to that of the target. Crop rotations are described as successions between non-competitive crops or practices that encourage certain weeds on the one hand and cleaning crops or practices on the other. The latter mainly target diaspores that have a lifespan inferior to the planned cleaning duration. The allelopathic after-effects show three mechanisms. In temperate climates, rotations may be complex with respect to the diversity of crop and weed phenologies. Combinations of cultural interventions must take into account the mechanisms involved, particularly because some results could cancel each other out.

Abstract Most of the people think that weeds are not useful, so they should be eradicated in any case. However weeds have numerous secondary metabolites of medical utility. These secondary metabolites serve as a treatment for many psychological, physical and pharmacological disorders of human body. The essential oils (EOs) extracted from weeds could be utilized as aromatherapy to cure several ailments. This review highlights the role of EOs in aromatherapy, health benefits of aromatherapy by essence or EOs of weeds, methods to extract aroma or EOs, their mode of action, quality and storage issues of EOs, scope and future trends in aromatherapy.

Abstract In the fieldof weed science,data transformation techniques are of frequent use while evaluating investigating weed count data. Even after having its criticism, data transformation still remains as a very popular technique because the reasons for its use are quite greater than its non-use. Depending on the functional relationship existing between mean and variance of the weed count data, suitable transformations like logarithmic, square root and angular, should be used.

Abstract The use of weeds as insectary plants is an emerging management tactic by agroecologists to sustain beneficial insect species. Fallow lands have always been used by insects, and are an important part of their diet in fragmented ecosystems. Weeds provide nectar and floral resources to beneficial insects, and provide resources to keep those insects within a field in between flowering events. Using weeds as a tool in agricultural production reliant on pollination allows farmers to increase yield, end herbicide use, and increase biodiversity of both plants and insects. Native weeds expand the range of native insects from natural areas into agroecosystems, supporting insects that buffer against lapses in pollination by agricultural honey bees. Weeds also support parasitoid and predatory insects by providing nectar and pollen to adults, as well as alternative prey. This review examines the plant-insect ecological interactions supported by weeds left within a farm, and their potential role in supporting pollinators and parasitoids.

Abstract Parthenium hysterophorus, one of the world’s most invasive weeds, is accountable for enormous losses to the biodiversity, agriculture, and even the health of human beings and animals. It is regarded as immensely prolific weed and most awful in crop production which devastated all the useful crops. However, various studies revealed that Parthenium can be used in agriculture in different form. In agriculture, it can be used as biopesticides, green manure, compost, soil amendment values, and vermi composting. Being a competitive weed, it consumes more and more nutrients from the soil and hence, the plant is rich in nutrients. During premature stage, i.e. before flowering, the plant is uprooted from field and burying it in the soil produces higher quality organic manure. Green manure and compost used improves the physical, chemical and biological properties of soil, increased the yield of agricultural crops. Numerous studies show that it has also insecticidal and pesticidal properties to control several insect pests in agricultural crops. This review briefly discusses the application of Parthenium in agriculture concluded by various researchers.