Investigation of Types and Hazard of Weeds in Coffea arabica Orchads in Nujiang River Basin

[Objective] Through the investigation of weeds in Coffea arabica orchads in NuJiang River basin, this study aimed to provide scientific guidance for the weed control and improving the ecological and economic benefits of the plantation of Cof- fea arabica. [Method] The types of weeds and the characteristics of weed occur- rence in Coffea arabica orchads in Nujiang River basin were investigated from July to August in 2012. [Result] The results showed that there were 69 types of weeds belonging to 21 families in Coffea arabica orchads. The predominant harmful types were shown as follows： Commelina nudiflora L. ＋ Leptochloa chinensis, Cyperus ro- tundus L. ＋ Bidens pilosa L. ＋ Eleusine indica, Imperata cylindrical ＋ Ageratum conyzoides L. ＋ Eupatorium odoratum L., Ageratum conyzoides L. ＋ Digitaria san- guinalis （L.） Scop. The preponderant weeds consisted mainly of 10 species, namely, Cyperus rotundus L., Commelina nudiflora L., Leptochloa chinensis, Digitaria san- guinalis （L.） Scop, Imperata cylindrical, Bidens pilosa L., Ageratum conyzoides L, E- upatorium odoratum L., Eleusine indica and Chenopodium serotinum L. [Conclusion] The result from this study is of great significance for the plantation of Coffea arabica in Nujiang River basin, as well as the control of weeds.

Chemical Control of Herbicide Monosulfuron Plus Propazine 44% WP against Weeds in Millet Fields and Study on Factors Influencing Yield of Millet

[Objective] The paper was to resolve the poor efficacy or phytotoxicity problems in promotion of herbicide monosulfuron plus propazine 44% WP. [Method] Using orthogonal test and Duncan＇s new multiple range statistical analysis with four factors four levels and three factors two levels, the effects of factors such as herbi- cide dose, irrigation water volume, quality of soil preparation and soil moisture content on chemical control of monosulfuron plus propazine 44% WP against weeds and millet yield were compared in the test. [Result] Seven factors all had great impact on control effect of monosulfuron plus propazine 44% WP against weeds, of which her- bicide dose, irrigation water volume, quality of soil preparation and soil moisture content were the most important factors affecting millet yield. According to millet yield and economic benefit, the optimal scheme to ensure safe, efficient and economic control of monosulfuron plus propazine 44% WP against weeds was as follows： the dose of monosulfuron plus propazine 44% WP was 1 800 g/hm2, the soil was treat- ed after sowing and before seedling emergence; the soil should be smooth and sol- id; the soil moisture should reach 15%; the fields should not be irrigated after herbi- cide application, and the damage of weeds in millet fields could be effectively con- trolled within 45 d during high efficacy duration, especially the damage of dicotyledonous weeds. [Conclusion] The study provided useful information for comprehensive technology of weeds control and ensuring high yield and good harvest of millet.

Effects of Rice-duck Mutualism on Diseases Insect Pests and Weeds and Economic Benefits

[Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field. [Method] Comparison of the incidence of weeds, sheath blight and insects pest under rice-duck mutualism, conventional cultivation and control treatment, the yield and economic benefits were analyzed under the 3 treatments. [Result] Average occurrence of weeds in rice-duck mutualism group decreased by 2.33 and 52.0g ind/m^2 compared with that in conventional cultivation and control treatment ; the control rate of mutualism was up to 75% against rice hopper, but just between 25% -60% against rice leaf roller and Chilo suppressalis. The rates of diseased plant and diseased bell against rice sheath blight were higher and disease indices were lower compared with control group. The yield of mutualism group was identical with conventional cultivation, Which was greatly higher than that of control group. The results suggested an higher economic benefits and lower cost benefit ratio for rice-duck mutualism treatment. [Conclusion] Rice-duck mutualism gives birth to a positive effect to control the diseases, insect pests and weeds, as well as to economic benefits, providing basis on extension of rice-duck mutualism system.

Influence of Adjuvants on the Efficacy of Tolpyralate plus Atrazine for the Control of Annual Grass and Broadleaf Weeds in Corn with and without Roundup WeatherMAX^®

Tolpyralate is a new HPPD-inhibiting herbicide that is efficacious on annual grass and broadleaf weed species in corn. For maximum herbicide performance of tolpyralate, it is recommended that atrazine is tank mixed with tolpyralate along with the adjuvants methylated seed oil concentrate (MSO) plus urea ammonia nitrate (UAN). A common use pattern of tolpyralate plus atrazine will be in a tank mix with Roundup WeatherMAX®due to the high proportion of corn acres that are seeded to Roundup Ready®hybrids in Eastern Canada. There is no information in the peer-reviewed literature if the adjuvant system in Roundup WeatherMAX®is adequate for optimal herbicide performance of tolpyralate plus atrazine, or if MSO and UAN are still required. Six field trials were conducted over two years near Ridgetown and Exeter, ON, Canada to determine if adjuvants are still required when tolpyralate plus atrazine is tank mixed with Roundup WeatherMAX®in corn. Tolpyralate plus atrazine plus MSO and Roundup WeatherMAX®plus tolpyralate plus atrazine provided excellent control of velvetleaf, pigweed spp, common ragweed, lambsquarters, ladysthumb, wild mustard, flower-of-an-hour, barnyardgrass and green foxtail in this study. Results of this study show that in the absence of Roundup WeatherMAX®, weed control with tolpyralate plus atrazine was improved substantially with the addition of MSO;however, there was little to no increase in weed control with the addition of UAN. When tolpyralate plus atrazine was co-applied with Roundup WeatherMAX®, there was no improvement in weed control with the addition of MSO and/or UAN.

Control Efficiency and Crop Safety of 20% Cyhalofop-butyl WP on Grass Weeds in Direct Seeded Rice Fields

The purpose was to define the control efficiency and safety of 20% cy- halofop-butyl WP on grass weeds in direct seeded rice fields, in order to provide the basis for chemical weeding. This study measured Leptochloa chinensis（L.） Nees, Echinoch/oa crusgalli （L.） Beauv and other gramineous weed control efficiency with four concentrations of 20% cyhalofop-dutyl WP and 100 g/L cyhalofop-dutyl EC in direct seeded rice fields, and analyzed the yield-increasing effect and safety of rice. The results showed that 20% cyhalofop-butyl WP had a good control efficiency on grass weeds such as Leptochloa chinensis（L.） Nees, Echinoch/oa crusgalli（L.） Beauv and other grasses. The effective dosage of 90-150 g/hm2 was over 90.7% on Lep- foch/oa chinensis（L.） Nees and the comprehensive control effect of the grass weeds was above 86.7%, which was basically consistent with 100 g/L cyhalofop-dutyl EC. Furthermore, 20% cyhalofop-dutyl WP was high security for direct seeded rice fields. The yield of rice was increased by 10.18%-11.22% after spraying herbicide. There- fore, 20% of cyhalofop-dutyl WP can be used as a special herbicide for controlling Leptochloa chinensis（L.） Beauv in direct seeded rice fields, and has a good applica- tion prospect.

Chlorobenzenes in waterweeds from the Xijiang River (Guangdong section) of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes （CBs） in both water and waterweeds collected from 4 stations in the Xijiang River （Gangdong section） of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs （ZCBs） in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ZCBs in waterweeds ranged from 13.53×10^2μg/g to 38.27×10^2μg/g dry weight （dw）. There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs （DCBs）, whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip （bioconcentration factor） of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was： Fengkai County 〈 Yunan County 〈 Yun＇an County 〈 Gaoyao County according to the ZCBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River .

Damage and Control of Poisonous Weeds in Western Grassland of China

Western grassland is the main source of living and means of production of western inhabitants. For many years, desertification and poisonous-weeds growth in grassland were resulted from over-grazing, over-reclaiming, over-spading and population growth. Western natural ecological environment is destroyed severly. Meanwhile, it has restricted the sustainable development of animal husbandry. The fast spreading poisonous-weeds, which caused grassland ecology unbalance, is one of the considerable bioecology problems and an important index of grassland degeneration. Based on analysis and induction of previous data, this article introduced the situation of poisonous-weeds disaster of western grassland in recent decades, category and distribution of poisonous-weeds, integrated control and reasonable utilization.

Evaluation of soil flame disinfestation(SFD) for controlling weeds,nematodes and fungi

Soil flame disinfestation(SFD) is a form of physical disinfestation that can be used both in greenhouses and on field crops. Its use for soil disinfestation in different crop growing conditions makes it increasingly attractive for controlling soilborne pathogens and weeds. But little is known about the effect on weeds and soilbrone diseases. This study reports on greenhouses and field crops in China that determined the efficacy of SFD to control weeds, nematodes and fungi. It also determined the impact of SFD on the soil physical and chemical properties(water content, bulk density, NO3^–-N content, NH4^+-N content, conductivity and organic matter) in three field trials. A second generation SFD machine was used in these trials. SFD treatment significantly reduced weeds(>87.8%) and root-knot nematodes(Meloidogyne incognita)(>98.1%). Plant height and crop yield was significantly increased with SFD treatment. NO3^–-N and NH4^+-N increased after the SFD treatment, and there was also an increase in soil conductivity. Water content, bulk density and organic matter decreased significantly in the soil after the SFD treatment compared to the control. Soil flame disinfestation is a potential technique for controlling weeds and diseases in greenhouses or in fields. SFD is a non-chemical, safe, environmentally-friendly soil disinfection method.

Herbicidal activity of Aureobasidium pullulans PA-2 on weeds and optimization of its solid-state fermentation conditions

Fungal strain PA-2 was isolated from infected poplar leaves from the Ping’an District, Haidong City of Qinghai Province, China. Based on the culture characteristics and the internal transcribed spacer(ITS) sequence of its 16S r DNA, the strain was identified as Aureobasidium pullulans. The culture and metabolites of strain PA-2 showed high herbicidal potential to five tested weeds Galium aparine var. tenerum, Chenopodium album, Malva crispa, Polygonum lapathifolium and Avena fatua. For the in vitro test, 5 days after the detached leaves were inoculated with PA-2 culture, all leaves infected by the hyphae and became black and rotten. For the in vivo test, a metabolite filtrate of PA-2 culture was sprayed over the living weed plants, and five days after inoculation, the weed plants became withered and necrotic. Seven days after inoculation, the fresh weight reductions of G. aparine var. tenerum, C. album, M. crispa, P. lapathifolium and A. fatua were 87.25, 78.46, 82.25, 62.11, and 80.27%, respectively. Galium aparine var. tenerum and M. crispa exhibited significant reductions in fresh weight. The bio-safety test on the five crops showed no significant plant height reductions, which was also observed for wheat(Triticum aestivum), faba bean(Vicia faba), and barley(Hordeum vulgare). By contrast, oilseed rape(Brassica napus) and pea(Pisum sativum) exhibited light spots but no significant reductions in plant height. These results indicated that A. pullulans could be a potential microbial herbicide for the control of the target weeds in crops. Optimization of the carbon and nitrogen sources for cultural media and substances for solid-state fermentation indicated that PA-2 had better colony growth and spore production with the optimal carbon source of glucose(C4), nitrogen source of soybean flour(N2), and the optimal substance was wheat bran. The results in this study provide useful information for the development ofA. pulluans PA-2 as an herbicide for bio-control of the weed.

Synergistic Effects of Herbicide Adjuvants on Weeds Control and Safety Determination in Field Application

The effects of 9 plant adjuvants on the control of Stellaria japonica and Poa pratensis by 3 herbicidesor mixtures,including MCPA-Na+Clethodim,Atrazine and Bentazon,were studied by pot experiments.The results showed that all these 9 plant adjuvants could significantly promote the control effects of MCPA-Na+Clethodim on 2 weeds,except Jiabajin for Poa pratensis.The control effect on plant number and fresh weight of Stellaria japonica increased by 90.6%~100.0%and 47.6%~56.2%respectively 10 d after the treatment,and 25.1%~96.4%and 17.7%~90.4%for Poa pratensis respectively.Pharmacodynamics,Doctor lemon oil,Pamiere,Beirunsu and Wynote had better synergistic effects.Plant adjuvants had little synergistic effect on Atrazine and Bentazon in the early stage which was 10 d after the treatment.However,when it was 20 d after the treatment,adjuvants like Yaoxiaoling,Pamiere and Beirunsu could significantly increase the control effect of Atrazine on Stellaria japonica.Yaoxiaoling,Jiabajin and Beirunsu could promote the synergistic effect of Bentazon on Poa pratensis.Adding herbicide Yaoxiaoling could increase the herbicide control effect,fresh weight control effect,plant height and fresh weight inhibition rate of weeds in maize and flax fields.And the herbicide phytotoxicity was not obvious.The combinations of plant adjuvants with 4 herbicides including Atrazine,Nicosulfuron Mesotrione Atrazine,Nicosulfuron Atrazine,and Bentazon;had better control effects on weeds in maize fields,while MCPA-Na+Clethodim+adjuvants had better control over weeds in flax fields.

Effects of Paddy Field Rotation on Diseases,Pests and Weeds of Rice

[ Objective] The paper was to explore ecological effect of paddy field rotation on reducing disease, pests and weeds of rice. [ Method] With long-term continuous cropping rice as control, according to field location experiments for consecutive 14 years, the effects of paddy field rotation on diseases, pests and weeds of rice were studied in details. [ Result] Paddy field rotation in some extent could reduce diseases, pests and weeds of rice. The diseased plant rate and disease in- dex of rice sheath blight in early rice under paddy field rotation treatment were averagely 10% and 0.4% lower than those in continuous cropping treatment, respec- tively. The diseased plant rate and disease index of rice sheath blight in late rice were 17.7% and 13.3% lower than those in treatments with continuous cropping mode, respectively. The diseased plant rate and disease index of rice false smut in both early rice and late rice under rotation treatments were lower than those in treatments with continuous cropping mode. White leaf rate caused by rice leaf roller and dry heart rate caused by striped rice borer under rotation treatments were significantly lower than those under continuous cropping treatment. The growth status of weeds under rotation treatments was weaker than that under continuous cropping treatment. [ Conclusion] The paper has important significance on alleviating diseases, pests and weeds of rice and improvement of ecological environment of farmland, and provides theoretical basis for sustainable development of agriculture.

Control Effects of 3 Kinds of Herbicides against Weeds in Dogbane (Apocynum venetum) Field

[ Objective] The paper was to explore the control effects of 3 kinds of herbicides against weeds in dogbane （Apocynum venetum） field. [ Method ] Using haloxyfop-R-mithyl and quizalofop-ethyl EC specifically killing monagenns gramineous weeds and chipton specifically killing dicotyledonous broad-leaf weeds, the control test against weeds in 2-year-old dogbane field was carried out. [ Result ] Haloxyfop-R-mithyl had good control effect against gramincous weeds, and its control effect against both barnyard weed （ Echinochloa crusgalli） and green bristleweed （ Setaria viridis ） was greater than 35.0% ; the control effects of quizalofop- ethyl EC against barnyard weed and green bristleweed were 14.8% and 28.6%, respectively; chipt0n had good control effect against Chenopodium album, and the control effect reached 30.8%. Moreover, 3 herbicides did not cause damage to dogbane. [ Conclusion] The study provide theoretical basis for completing cultivation technique of dogbane.

A Review of Research Directions and Research Methods of Farmland Weeds

Farmland weeds are an important part of farmland ecosystems.Research on farmland weeds is one of the major research fields in agricultural ecology.It is of great significance for achieving high yield,high quality and high efficiency in agriculture.In recent years,research on farmland weeds has focused on investigation of weed communities,research on weed seed banks,and research on weed control.These three research directions complement each other.Among them,the investigation work of weed communities and the research of weed seed banks are helpful for us to grasp the occurrence of farmland weeds more accurately and provide references for the control of farmland weeds.This article summarizes the research directions of farmland weeds in recent years(weed community investigation,weed seed bank,weed control)and the research methods used,provide reference value for the follow-up research work of farmland weeds,and provide theoretical support for promoting the development of rural ecological industry and building beautiful villages.

Estimating Carbon Capture Potential of Fallow Weeds in Rice Cropping Systems

Weeds occurred during the fallow season can well perform the function of carbon(C)capture due to receiving little human disturbance.This study aimed to evaluate the C capture potential of fallow weeds in rice(Oryza sativa L.)cropping systems.A six-region,two-year on-farm investigation and a three-year tillage experiment were conducted to estimate C capture in fallow weeds in rice cropping systems.The on-farm investigation showed that the average mean C capture by fallow weeds across six regions and two years reached 112 g m^(-2).The tillage experiment indicated that no-tillage practices increased C capture by fallow weeds by 80%on average as compared with conventional tillage.The results of this study not only contribute to an understanding of C capture potential of fallow weeds in rice cropping systems,but also provide a reference for including fallow weeds in the estimation of vegetative C sink.

Several Exotic Harmful Weeds in Beilun Port of Ningbo

An investigation was carried out in wharves, inspection yards, processing plants in Beilun Port and the surrounding areas. Five kinds of exotic harmful weeds were discovered and collected, and they were described and analyzed.

Preliminary Report on Species and Occurrence Regularity of Diseases,Pests and Weeds of Corn in Angola

[ Objective] The paper was to understand species of diseases, pests and weeds and their occurrence periods and dynamic changes of quantity during corn growing period in rainy and dry seasons in Angola. [ Method] Using systematic investigation method, the species and occurrence regularity of diseases, pests and weeds of corn in Pedras Negras farm （ Malanje）, Sanza Pombo farm （Uige） and Catete farm （Luanda） in the Mrican continent, the Republic of Angola, were studied in two dry seasons and a rainy season from 2011 to 2012. [ Result] The occurrence status of pests and diseases of corn during dry and rainy seasons were basically similar, and only individual diseases and pests had different incidence degrees. The corn varieties from the United States and Brazil had prominent advan- tages in resistance to diseases and barren. Due to different climate environments in dry and rainy seasons, the unearthed rate of weeds in fields was also different. Soil moisture had great impact on weed population and density. Soil layer depth greatly influenced unearthed speed and unearthed rate of weeds. [ Conclusion ] The study cleared species, occurrence period and harmful levels of pests, diseases and weeds of corn in three provinces of Angola.

Control Effect of 80% Nicosulfuron·Atrazine Water-dispersible Granules on Weeds in Spring Maize Field

[Objective] This study aimed to investigate the control effect of different concentrations of 80% nicosulfuron·atrazine water-dispersible granules on weeds in spring maize field. [Method] Maize field was sprayed with 300, 375, 450, 750 g/hm280% nicosulfuron·atrazine water-dispersible granules respectively, with 40 g/L nicosulfuron suspending concentrate and 38% atrazine suspending concentrate as control agents. Artificial weeding and control(CK) plots were set. [Result] Fresh weight control efficiency of 375-750 g/hm280% nicosulfuron·atrazine water-dispersible granules was significantly higher than that of 40 g/L nicosulfuron suspending concentrate and 38% atrazine suspending concentrate; no obvious phytotoxicity symptoms were observed after application of 300-450 g/hm280% nicosulfuron·atrazine waterdispersible granules; 750 g/hm280% nicosulfuron·atrazine water-dispersible granules posed certain impact on the growth of maize seedlings. Compared with control plots, various doses of 80% nicosulfuron·atrazine water-dispersible granules significantly improved the yield of maize. [Conclusion] In the present study, 375-450 g/hm280% nicosulfuron·atrazine water-dispersible granules exhibited high control effect on weeds in maize field and were safe for the growth of maize seedlings.

Technical Regulations for Integrated Prevention and Control of Weeds in Millet Fields in Hebei Province

According to the summary of experiments for many years, application scope, prevention and control principle and objects of technical regulation for integrated prevention and control of weeds in millet fields, as well as integrated control technologies including agricultural control, physical control and chemical control were studied, and the specific methods and technical indicators were determined.

Use of Gramoxone 20SL (Paraquat) Prior to Land Preparation in Controlling Aquatic Weeds in Wetland Areas of Bangladesh

Emergent aquatic weeds present in the monocropped fresh water wetland area of Bangladesh create a hazard in land preparation by developing dense stands. A field experiment was conducted at the farmers’ field of two villages namely Mahilara and Kashemabad under Gournadi Upazila of Barisal district, Bangladesh during October 2012 to evaluate the efficacy of Gramoxone 20SL (Paraquat) in controlling emergent aquatic weeds and to find out an appropriate dose of this herbicide. Three doses of Gramoxone 20SL at 1.96 l·ha-1, 2.00 l·ha-1 and 2.04 l·ha-1 were tried with an untreated control. All treatments were laid out in a randomized complete block design and replicated thrice. There were 8 different emergent weed species infesting the field among which the most dominant weed species were Eichhornia crassipes, Pistia stratiotes, Enhydra fluctuans, Monochoria vaginalis, Echinochloa crus-galli. The results revealed that, weed control efficiency was significantly affected by different herbicidal treatments. The treatments, Gramoxone 20SL at 2.00 l·ha-1 and 2.04 l·ha-1 were controlled in all the emergent aquatic weeds more than 85% infesting both the sites. Application of non-selective herbicide Gramoxone 20SL at 2.00 l·ha-1 prior to land preparation was most effective to suppress weed dry masses in both the site resulting reduced land preparation cost up to 78.93% as compared to manual weed control.

Study on Analysis Model of Millet Yield Loss Caused by Weeds in Summer Season Millet Field

Weed management in summer season foxtall millet field was studied by evaluating weed damage and exploring competition between weeds and foxtail millet, and a few fitting models were simulated and compared by employing field plot experiment and nonlinear regression analysis. The results showed that the millet yield losses and weed density were extremely significantly correlated. Among the tested models, the determination coefficient （ R2 ） of hyperbolic model was 0.997 12, and minimum residual sum of squares was 16.174, which was considered the optimal model to simulate the competition relation between weeds and millet. The predicted equation was Y = d/（ 1. 733 ＋ 0. 018d） ; the interspecific competitiveness of weeds was 0. 577 0 and the intraspecific competitiveness was 0.010 3 ; the maximum loss rate of millet yield was 55.56%. This study had established an analysis model with high gcodness-of-fit and practical prediction which could help weed management in summer season millet field.