Aquatic Weed Management Research Articles

수로와 강변의 습지에 발생한 수생잡초의 분포 및 방제 현황

수로, 하천, 호수, 강 주변에서 발생하는 수생잡초는 왕성한 생장으로 관개, 배수에서 유속 감소, 수생 생태계에 영향 등으로 막대한 피해를 입히고 수생잡초를 방제하기 위하여 많은 비용을 지출하고 있다. 따라서 본 연구는 수로, 하천, 강 주변 습지와 수중에서 발생하는 수생잡초와 침입식물의 분포 및 방제에 관한 정보를 분석하여 수생잡초의 효과적인 관리대책 수립에 필요한 자료를 제공하고자 하였다. 수로, 저수지, 호수 주변의 수생잡초는 갈대, 나도겨풀, 줄, 망초, 개망초, 소리쟁이, 개기장, 미국가막사리, 부들, 주요 강변의 습지에서는 바랭이, 갈대, 소리쟁이, 쑥, 환삼덩굴, 피, 미국가막사리, 고마리가 우점하였다. 수로 및 호수에서 발생한 침수잡초는 검정말, 나자스말, 대가래, 말즘, 붕어마름, 생이가래, 마름이 우점하였다. 습지에서 외래잡초는 토끼풀, 달맞이꽃, 개망초, 망초, 미국가막사리, 메귀리, 돼지풀, 도꼬마리, 미국개기장, 소리쟁이가 우점하였다. 수생잡초 방제는 기계적, 화학적, 생물적 방법에 의존하고 있으며, 앞으로 우리나라에서 습지에서 수생잡초와 외래잡초를 방제하기 위하여 수생잡초의 주기적인 모니터링과 기계적, 화학적 방제를 포함한 종합잡초관리 체계에 관한 연구가 요망된다. Many irrigated and drainage canals, reservoirs, lakes, and rivers are choked by the explosive growth of aquatic weeds, resulting in enormous direct loss in Korea. Distribution of aquatic weeds and exotic invasive plant species in irrigation and drainage waterways, and riparian wetlands was reviewed to provide basic information for management of aquatic weeds and invasive plant species in wetlands. Dominant emergent weeds in canals, reservoirs and lakes were Phragmites communis, Leersia japonica, Zizania latifolia, Conyza canadensis, C. annuus, Rumex crispus, Panicum dichotomiflorum, Bidens frondosa, and Oenothera odorata. Dominant emergent weeds in wetlands of rivers include Digitaria sanguinalis, P. communis, R. crispus, Artemisia princeps, Humulus japonicus, Echinochloa crusgalli, B. frondosa, and Persicaria thunbergii. In irrigation and drainage canals and lakes, dominant submersed weeds were Hydrilla verticillata, Najas minor, Potamogeton malaianus, P. crispus, Ceratophyllum demersum, Myriophyllum verticillatum, Salvinia natans, and Trapa natans. Dominant exotic weeds in wetlands include Trifolium repens, O. odorata, C. annuus, B. frondosa, Avena fatua, Ambrosia artemisiifolia, X. strumarium, and P. dichotomiflorum. Approaches to aquatic weed control were mechanical, chemical and biological control techniques. Periodic monitoring of aquatic weeds and exotic weeds, and their integrated management studies are needed in waterways and riparian wetlands in Korea.

Management options of invasive Elodea nuttallii and Elodea canadensis

Elodea nuttallii and Elodea canadensis , two invasive submerged and rooted aquatic macrophyte species, are receiving increasing attention for their rapid and lasting invasion of many freshwater habitats throughout Europe, Asia and Australia. This review summarizes the present scientific knowledge about means of controlling E. nuttallii and E. canadensis within of aquatic weed management programs. Both species exhibit high growth rates with a high tolerance to wide ranges of environmental conditions, low vulnerability to grazing and other stress factors, high distribution and reproduction potential, and relatively high resistance to common conventional aquatic weed management procedures. Possibilities for the further use of harvested Elodea biomass are presented and novel approaches to the improvement of the monitoring and management of Elodea plagues are discussed.

Water hyacinth [Eichhornia crassipes (Mart.) Solms.] engineered soil nutrient availability in a low-land rain-fed rice farming system of north-east India

A study was conducted to investigate the mulch role of water hyacinth (Eichhornia crassipes) on soil properties of a lowland rain-fed rice farming system in north-east India. The green mulch had higher carbon and nutrient contents as compared to its compost and vermicompost forms, and so were the hemicellulose, cellulose and lignin. Significant reduction in C/N ratio from fresh water hyacinth indicated rapid N release while composting. Over all, mulching significantly (p<0.05) increased soil C, total N, available P and K as compared to the non-mulched plots. Nonetheless, soil C was greater in the green mulch plots, followed by compost and vermicompost plots. Net N mineralization rate also followed similar patterns. Upon comparison with other aquatic weedy species, E. crassipes had 20–50% more C and 10–40% more N in its residues. Likewise, the compost prepared out of E. crassipes also seems to be of good quality as indicated by a C/N ratio less than 25, as compared to Hydrilla spp., Najas spp., Ottelia spp. and Pistia stratiotes. It is therefore suggested that recycling of water hyacinth can be an ecofriendly aquatic weed management strategy to improve soil health and nutrient redistribution through a faster turnover that can engineer sustainable agricultural production in the tropical soils.

Grass Carp: A Fish for Biological Management of Hydrilla and Other Aquatic Weeds in Florida

Abundant growth of aquatic plants causes serious problems in ponds, lakes, rivers, and irrigation and drainage throughout Florida. In some situations, native aquatic plants become weeds, but most often exotic plants introduced from areas outside the state flourish under the favorable growing conditions found in Florida. Long-term economical solutions to Florida’s aquatic weed problems have been elusive and there is a need for control techniques to alleviate aquatic weed problems. This 6-page fact sheet provides information on a biological method, the grass carp, for management of some of Florida’s aquatic weed problems. Written by David L. Sutton and Vernon V. Vandiver, Jr., and published by the UF Department of Fisheries and Aquatic Sciences, November 2012. &#x0D; http://edis.ifas.ufl.edu/fa043

Effects of the herbicide imazapyr on juvenile Oregon spotted frogs

Conflict between native amphibians and aquatic weed management in the Pacific Northwest is rarely recognized because most native stillwater-breeding amphibian species move upland during summer, when herbicide application to control weeds in aquatic habitats typically occurs. However, aquatic weed management may pose a risk for aquatic species present in wetlands through the summer, such as the Oregon spotted frog (OSF, Rana pretiosa), a state endangered species in Washington. Acute toxicity of herbicides used to control aquatic weeds tends to be low, but the direct effects of herbicide tank mixes on OSFs have remained unexamined. We exposed juvenile OSFs to tank mixes of the herbicide imazapyr, a surfactant, and a marker dye in a 96-h static-renewal test. The tank mix was chosen because of its low toxicity to fish and its effectiveness in aquatic weed control. Concentrations were those associated with low-volume (3.5 L/ha) and high-volume (7.0 L/ha) applications of imazapyr and a clean-water control. Following exposure, frogs were reared for two months in clean water to identify potential latent effects on growth. Endpoints evaluated included feeding behavior, growth, and body and liver condition indices. We recorded no mortalities and found no significant differences for any end point between the herbicide-exposed and clean-water control frogs. The results suggest that imazapyr use in wetland restoration poses a low risk of direct toxic effects on juvenile OSFs.

Optimising diquat use for submerged aquatic weed management

An experimentally derived prediction tool is under development which aims to assess potential deactivation of diquat caused by water and deposits on plant leaf surfaces in New Zealand water bodies, where aquatic weeds are targeted for diquat treatment. Optimising the use and success of diquat is important not only in managing public confidence in the use of aquatic herbicides, but also in minimising financial risk from failed treatments. Our approach focuses on characterising lake water quality and plant condition factors in these lakes to identify parameters that might be useful indicators of diquat deactivation potential. Water samples have been collected at 3-month intervals from lakes receiving large scale treatment for weed control. Samples have been analysed for turbidity, suspended solids, chlorophyll a, conductivity and dissolved anions. Samples have also been spiked with 1 mg l−1 diquat to measure loss from adsorption and/or absorption. Shoot samples were also collected from targeted weed species at each sampling site and the amount of organic and inorganic deposits on plants has been measured and then added to a second diquat spiked sample to assess potential additional diquat loss from these deposits. Our results have shown deactivation from deposits on plant surfaces which is highly correlated with turbidity, including inorganic suspended solids and total suspended solids. A plant “dirtiness” scale has been devised to help predict the likely success or risk of diquat failure prior to any decision to proceed with treatment. Deactivation in water was only weakly linked to total suspended solids. Our failure to find significant correlation with the water quality factors measured may reflect the need for more detailed analysis of the particle size and composition of suspended solids and future research will address these issues.

Nipping aquatic plant invasions in the bud: weed risk assessment and the trade

The importation and sale of ornamental pond and aquarium plants is the most important pathway for the introduction of potential aquatic weeds into and subsequent spread of these within a country. Most current aquatic weeds were at one time deliberately imported for ornamental use. This article discusses a weed risk assessment approach to evaluating new potential weeds. It assesses the potential invasiveness of an aquatic plant based on its habitat versatility, competitive ability, reproductive output and dispersal mechanisms, range of potential impacts, potential distribution and resistance to management activities. The Aquatic Weed Risk Assessment Model (AWRAM) has been used to evaluate potential aquatic weeds in New Zealand, Australia and the USA. A similar approach could be used to guide the management of aquatic weeds in Europe. Banning the importation of highly ranked species effectively keeps biosecurity risks off-shore. Assessment of aquatic plant trade patterns, especially volumes of high-risk species, along with knowledge of current and potential distribution of those species and ease of management, are all factors to be considered when evaluating candidate plants for prevention of sale and distribution. This is a highly effective way of restricting both long-distance dispersal and density of propagules. A cooperative approach involving researchers, policy and trade representatives has been an effective way to achieve regulation of this risk pathway. European initiatives to prevent the distribution of potential aquatic weeds include the preparation of lists of known invasive aquatic species by the European and Mediterranean Plant Protection Organization (EPPO), with recommendations to member countries to consider measures to prevent their spread (e.g. banning importation of, banning sale and distribution of, and undertaking control programmes against those species). Belgian initiatives include an upcoming Royal Decree concerning the importation, exportation and possession of non-native invasive species, development of codes of conduct with the horticultural sector and prohibiting the sale, purchase and intentional release of these species in the wild. This article reviews these approaches and discusses other species of concern.

A novel approach to aquatic weed control and habitat restoration using biodegradable jute matting

This technical paper presents results from pilot field trials conducted on the novel use of a biodegradable jute material to eradicate the highly invasive aquatic macrophyte Lagarosiphon major Ridley from Lough Corrib, Ireland. The results demonstrate the ability of the jute material to comprehensively kill L. major and to restore native macrophyte communities to areas of the lake that were previously overgrown with this priority invasive species. To date, eight indigenous plant species (four charophytes and four angiosperms) have been recorded growing through the loose-weave jute fabric. However, no Lagarosiphon has been recorded as doing so. This material has the potential for broader application in the management of nuisance aquatic weeds and in the restoration of native flora extirpated by these alien species.

A Rotary-wing Unmanned Air Vehicle for Aquatic Weed Surveillance and Management

This paper addresses the novel application of an autonomous rotary-wing unmanned air vehicle (RUAV) as a cost-effective tool for the surveillance and management of aquatic weeds. A conservative estimate of the annual loss of agricultural revenue to the Australian economy due to weeds is in the order of A$4 billion, hence the reason why weed control is of national significance. The presented system locates and identifies weeds in inaccessible locations. The RUAV is equipped with low-cost sensor suites and various weed detection algorithms. In order to provide the weed control operators with the capability of autonomous or remote control spraying and treatment of the aquatic weeds the RUAV is also fitted with a spray mechanism. The system has been demonstrated over inaccessible weed infested aquatic habitats.

Introduction of floating gardening in the north-eastern wetlands of Bangladesh for nutritional security and sustainable livelihood

AbstractFloating gardening is a form of hydroponics or soil-less culture. It is an age-old practice of crop cultivation in the floodplains of southern Bangladesh, where aquatic plants such as water hyacinth (Eichhornia crassipes) are used to construct floating platforms on which seedlings are raised and vegetables and other crops cultivated in the rainy season. The platform residue is used in the preparation of beds for winter vegetable gardening. Floating gardening was introduced in 2006 on a pilot-scale in the north-east wetlands of the country, as a contribution to food security and as a supplementary income for the marginalized community. The overall experience of floating cultivation in three selected villages was encouraging. Local people became aware of this new farming system and their level of knowledge improved. Communities were mobilized into groups to make floating platforms, and platform residues were later used to establish winter gardens. Cultivation was successful on both types of plot, and vegetables were both consumed by the producers and sold in the market. The input–output analysis revealed floating gardening to be a feasible alternative livelihood option for the wetland dwellers. The method provided targeted landless people with parcels of land in the monsoon, enabling them to grow vegetables. Floating gardening and associated winter gardening appear to have the potential for introduction to other parts of the world where aquatic weed management is a major problem.

Segurança das condições de aplicação de herbicidas com aerobarco em plantas daninhas aquáticas no lago da Hidrelétrica de Jupiá

Os objetivos deste trabalho foram quantificar as exposições dérmicas (EDs) e respiratórias (ERs) proporcionadas ao piloto e ao seu ajudante nas aplicações de herbicidas para o controle de plantas daninhas aquáticas com aerobarco; classificar essas condições de trabalho em seguras ou inseguras; e calcular a necessidade de controle das exposições (NCE) e o tempo de trabalho seguro (TTS). O aerobarco utilizado tinha casco de alumínio (4,85 x 2,42 m) e acionamento por hélice acoplada a motor a gasolina de 350 HP. O equipamento de pulverização era composto por bomba de diafragma com fluxo máximo de 49,69 L min-1, pressão máxima de 25 kg cm-2, acionada por motor a gasolina de 4 HP, e tanque de calda de 189 L. A barra de pulverização de alumínio era composta de duas seções laterais de 3 m, posicionadas na linha entre o encosto do banco do piloto e o início da estrutura protetora da hélice. Cada seção da barra tinha seis bicos com pontas de jato plano com indução de ar AI 100 03, espaçados de 0,5 m, e uma ponta OC 20 fixada em cada extremidade. O conjunto de pontas pulverizava faixas de 6 m de largura e aplicava o volume de calda de 200 L ha-1. O sistema tinha gerenciador de fluxo, controlado por central eletrônica acoplada a DGPS (com precisão submétrica), para corrigir automaticamente a vazão em função de alterações na velocidade real da embarcação. As EDs e ERs aos herbicidas foram calculadas com os dados substitutos das exposições às caldas, avaliadas com os traçadores cobre e manganês adicionados às caldas. As exposições foram extrapoladas para uma jornada de trabalho de seis horas. A segurança das condições de trabalho foi determinada com o cálculo da margem de segurança (MS), utilizando-se a fórmula MS = (NOEL x 70)/(QAE x 10), em que QAE = quantidade absorvível da exposição. As condições de trabalho foram classificadas em seguras, se MS&gt;1, ou inseguras, se MS&lt;1. As exposições proporcionadas pelas condições de trabalho foram de 10,65 mL de calda por dia para o piloto e de 16,80 mL por dia para o ajudante, que fica sentado em uma cadeira a 2,0 m à frente do piloto e da barra de pulverização. Classificaram-se como seguras as aplicações dos herbicidas glyphosate (Rodeo, 6 L ha-1), 2,4D (DMA 806 BR, 8 L ha-1) e fluridone (Sonar AQ, 0,4 L ha-1), para o piloto e o seu ajudante. Classificou-se como insegura a aplicação do herbicida diquat (Reward, 4,0 L ha-1) para as duas condições de trabalho, cujas necessidades de controle das exposições calculadas foram de 65% para o piloto e de 78% para o ajudante do piloto.

Safe Use of Glyphosate-containing Products in Aquatic and Upland Natural Areas

Land and water managers who apply herbicides to control invasive plant species and other nuisance vegetation strive to minimize environmental impacts as a matter of policy and daily operations. It is, therefore, not surprising that concern has been expressed and many questions asked relative to recent publications by Relyea (2005a, 2005b, 2005c), which implicate use of glyphosate-containing herbicides in global decline of amphibians. The purpose of this article is to put these recent publications in perspective relative to aquatic and terrestrial natural area weed management and explain why land managers should continue to use glyphosate-containing products to protect managed habitats from weeds without concern for unreasonable adverse environmental impacts. This document is SS-AGR-104, one of a series of the Agronomy Department, Center for Aquatic and Invasive Plants, UF/IFAS Extension. Original publication date February 2006.

A review of aquatic weed biology and management research conducted by the United States Department of Agriculture-Agricultural Research Service.

Ever-increasing demand for water to irrigate crops, support aquaculture, provide domestic water needs and to protect natural aquatic and riparian habitats has necessitated research to reduce impacts from a parallel increase in invasive aquatic weeds. This paper reviews the past 4-5 years of research by USDA-ARS covering such areas as weed biology, ecology, physiology and management strategies, including herbicides, biological control and potential for use of natural products. Research approaches range from field-level studies to highly specific molecular and biochemical work, spanning several disciplines and encompassing the most problematic weeds in these systems. This research has led to new insights into plant competition, host-specificity, and the fate of aquatic herbicides, their modes of action and effects on the environment. Another hallmark of USDA-ARS research has been its many collaborations with other federal, state action and regulatory agencies and private industry to develop new solutions to aquatic weed problems that affect our public natural resources and commercial enterprises.

Allelopathic Interactions and Allelochemicals: New Possibilities for Sustainable Weed Management

Weeds are known to cause enormous losses due to their interference in agroecosystems. Because of environmental and human health concerns, worldwide efforts are being made to reduce the heavy reliance on synthetic herbicides that are used to control weeds. In this regard the phenomenon of allelopathy, which is expressed through the release of chemicals by a plant, has been suggested to be one of the possible alternatives for achieving sustainable weed management. The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particularly of crop plants, or by using allelochemicals as natural herbicides. In the former case, a number of crop plants with allelopathic potential can be used as cover, smother, and green manure crops for managing weeds by making desired manipulations in the cultural practices and cropping patterns. These can be suitably rotated or intercropped with main crops to manage the target weeds (including parasitic ones) selectively. Even the crop mulch/residues can also give desirable benefits. Not only the terrestrial weeds, even allelopathy can be suitably manipulated for the management of aquatic weeds. The allelochemicals present in the higher plants as well as in the microbes can be directly used for weed management on the pattern of herbicides. Their bioefficacy can be enhanced by structural changes or the synthesis of chemical analogues based on them. Further, in order to enhance the potential of allelopathic crops, several improvements can be made with the use of biotechnology or genomics and proteomics. In this context either the production of allelochemicals can be enhanced or the transgenics with foreign genes encoding for a particular weed-suppressing allelochemical could be produced. In the former, both conventional breeding and molecular genetical techniques are useful. However, with conventional breeding being slow and difficult, more emphasis is laid on the use of modern techniques such as molecular markers and the selection aided by them. Although the progress in this regard is slow, nevertheless some promising results are coming and more are expected in future. This review attempts to discuss all these aspects of allelopathy for the sustainable management of weeds.Referee: Dr. Amrjits S. Basra, Central Plains Crop Technology, 5912 North Meridian Avenue, Wichita, KS 67204

Interactions between national and local strategies for the management of aquatic weeds

Interactions between national and local strategies for the management of aquatic weeds

Mechanical aquatic weed management in the lower valley of the R�o Negro, Argentina

Mechanical aquatic weed management in the lower valley of the R�o Negro, Argentina

Allelopathic aquatic plants for aquatic weed management

This report presents, results of a feasibility study of use of allelopathic aquatic plants for aquatic weed management. In order to establish a list of potential allelopathic plants, we selected 16 aquatic plants native to the southeastern United States and subjected them to two bioassays — one involving lettuce seedlings and one involving the aquatic plantLemna minor as the target species. The lettuce seedling bioassay was selected because it is a widely used, experimentally simple assay to determine allelopathic activity. However, it uses lettuce, a terrestrial plant, as the target species, and thus may be less appropriate for use with aquatic plants. TheL. minor assay involves an aquatic plant as the target species and so is more appropriate for our goals, but it is experimentally much more complex and time-consuming. The plants selected for study wereBrasenia schreberi, Cabomba caroliniana, Ceratophyllum demersum, Eleocharis acicuiaris, Eleocharis obf usa, Hydrilla verticillata, Juncus repens, Limnobium spongia, Myriophyllum aquaticum, Myriophyllum spicatum, Najas guadalupensis, Nymphaea odorata, Nymphoides cordata, Potamogeton foliosus, Sparganium americanum, and Val/isneria americana.Nymphaea odorata (leaves and petioles) inhibited 78 % of lettuce seedling radicle growth and 98 % ofL. minor frond production. Brasenia schreberi inhibited 82 % of lettuce seedling radicle growth and 68 % of L. minor frond production. These results suggest thatN. odorata andB. schreberi are both highly inhibitory and are therefore candidates for use in aquatic weed management. Results also suggest that the simple lettuce seedling assay is a reasonable first “easy” one to use in an attempt to determine allelopathic potential of aquatic plants.

An examination of the phytotoxicity of the water shield,Brasenia schreberi

Antialgal, antibacterial, and allelopathic properties of the submersed, aquatic, dicotyledonous water shield,Brasenia schreberi Gmelin (Cabombaceae), were examined. Extracts ofB. schreberi were found to inhibit the eukaryotic alga,Chlorella pyrenoidosa, and the prokaryotic alga,Anabena flosaqua, as well as nine different bacteria. Lettuce seedling bioassay showedB. schreberi to be allelopathic. These phytotoxic properties probably contribute to the observed dominance ofB. schreberi in aquatic environments and also make it a promising candidate for allelopathic plant management of aquatic weeds.

Residues of dalapon and TCA in sediments and irrigation water

AbstractWhen dalapon and TCA are used for the management of aquatic weeds in irrigation distribution systems, they are often applied to established stands of Typha spp. and Phragmites australis in autumn or early winter, after draining water from the system. It has been assumed that the herbicides would dissipate from the sediments within 6 weeks, so that water supplies could be safely restored. In field experiments the decay of dalapon and TCA in sediments followed the classical pattern for a microbially mediated process, with a slow lag‐phase, followed by a rapid phase of decline, but not to completion. Particularly for TCA, there was a final slow phase in which residues were sufficient to contaminate eluting water at concentrations much greater than the legally prescribed tolerance, even when the interval between herbicide treatment and water re‐supply was more than 6 weeks. Although the overall pattern of dissipation in the sediment was similar for the two herbicides, concentrations of TCA were higher than those of dalapon in the elution water, probably reflecting differences in herbicide mobility and elution efficiency. Dye tracers were used in three field experiments to investigate the efficiency of herbicide elution and carryover of contaminated water when canals were filled to capacity, drained and refilled. Together with the rate of dissipation from sediments, canal topography and draining efficiency determined the safety of the elution process in removing surplus residues before re‐supply of water for irrigation. In large‐scale management operations, where the dissipation interval was only 17‐19 days, the TCA was eluted from the sediment into flowing water in proportion to the square root of time, giving average concentrations over 3 days of discharge of more than 0.4gm−3. Ideally, the interval between spraying and water re‐supply should be extended beyond 6 weeks. Alternatively, herbicide use should be restricted, or provision made for elution of surplus residues and disposal of contaminated water to waste, or onto tolerant crops or fallow land.

Aquatic weed management in natural streams: the effect of shade by the marginal vegetation

(1978). Aquatic weed management in natural streams: the effect of shade by the marginal vegetation. SIL Proceedings, 1922-2010: Vol. 20, No. 2, pp. 1451-1456.