Weed Samples Research Articles

Sesame (Sesamum indicum L.) Response to Different Fertilizing System and Cover Crops in Weed Competition

AbstractBackground & objectives: This study was conducted to investigate the effect of different nutrition systems and cover crops on morphological traits, yield, yield components and competitive indices of sesame in competition with weeds. Materials & Methods: This research was carried out in the research farm of Sari Agricultural Sciences and Natural Resources University in 2016 as a randomized complete block design with three replications and eight treatments. Experimental treatments include: 1- sesame + soybean cover crop + without fertilizer, 2- sesame + millet cover crop + without fertilizer, 3- sesame + soybean cover crop + vermicompost, 4- sesame + millet cover crop + vermicompost, 5- sesame + soybean cover crop + chemical fertilizer, 6- sesame + millet cover crop + chemical fertilizer, 7- sesame + without weeding + without fertilizer (control) 8- sesame + weeding + chemical fertilizer (control). Also, two treatments of monoculture of sesame were considered as control (weed infestation and weed free). The traits studied in this experiment include weed density and weed biomass, competitive indices, yield and yield components, as well as morphological traits of sesame. Results: The results of weed sampling in three stages (10- leaf, seed dough and harvesting time) showed that the highest weeds density and biomass was in control with weed infestation and then in soybean cover crop with chemical fertilizer application. The results showed that fertilizer resources and cover crops had a significant effect on the grain yield, number of capsules per plant, seed number per capsule, 1000 seed weight, biological yield, as well as competition index (CI), so that the highest and lowest grain yields were observed in the treatment of millet with organic fertilizer (1630.22 kg.ha-1) and millet without fertilizer (413.33 kg.ha-1), respectively. The highest number of capsules per plant (41) was observed in weed control and the highest number of seeds per capsule (64.33 and 63.66) and 1000-seeds weight (2.56 and 2.53 g) in two treatments of weed control and millet cover crop with organic fertilizer application, respectively. Also, the highest rate of competition index (4.38%) was observed in millet cover crop with organic fertilizer, which showed significant effect of treatments on this index in sesame. Conclusion: The result of this experiment showed that millet cover crop, with decreasing weed density and biomass, increased sesame yield significantly. Furthermore, the use of organic fertilizers comparison to chemical fertilizers improves the properties of the soil and, also, the use of these fertilizers with the appropriate cover crops is a suitable strategy for sustainable agriculture in order to achieve greater yield and higher quality of the sesame. So, use of millet cover crop as well as organic fertilizer is recommended to improve sesame yield and proper weed management.

Occurrence and Distribution of Viruses Associated with Okra and Their Alternative Hosts in Kaduna and Zamfara States, Nigeria.

One of the major constraints to production of okra (Abelmoschus esculentus L.) in Nigeria and in particular in Kaduna and Zamfara States, is the problem of okra mosaic virus and okra leaf curl virus. This study was carried out to provide information on the occurrence and distribution of okra mosaic and okra leaf curl viruses on okra, in Kaduna and Zamfara states, Nigeria. A survey of okra-producing farms was carried out during dry and wet seasons of 2017 cropping season in Kaduna (Zaria, Lere, and Igabi Local Government Areas) and Zamfara (Gusau, Bungudu, and Zurmi LGAs) states. Leaf samples (15) of symptomatic okra plants were collected from each farm in the study area. The total number of plants and the number of symptomatic plants within each subplot were recorded, and the disease incidence was determined. Double Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DAS- ELISA) kit was used in the detection of Okra Mosaic Virus while Polymerase Chain Reaction (PCR) was employed for the detection Okra Leaf Curl Virus. The results showed that all the okra leaf samples tested for OLCV were negative in this study while OkMV was tested positve in all the samples with a recorded incidence of 20 % and 14 % in Kaduna and Zamfara states respectively, however, only 8 out of total weed samples were also tested positive for OKV, but all were tested negative to OLCV.

Analysis of the Fusarium graminearum Species Complex from Gramineous Weeds Near Wheat Fields in Jiangsu Province, China.

Several weed species are known as alternative hosts of the Fusarium graminearum species complex (FGSC), and their epidemiological significance in Fusarium head blight (FHB) has been investigated; however, scant information is available regarding FGSC occurrence in weeds near Chinese wheat fields. To evaluate the potential role of gramineous weeds surrounding wheat fields in FHB, 306 FGSC isolates were obtained from 210 gramineous weed samples in 2018 in Jiangsu Province. Among them, 289 were Fusarium asiaticum, and the remainder were F. graminearum. Trichothecene genotype and mycotoxin analyses revealed that 74.3% of the F. asiaticum isolates were the 3-acetyldeoxynivalenol (3ADON) chemotype, and the remainder were the nivalenol (NIV) chemotype. Additionally, 82.4% of F. graminearum isolates were the 15-acetyldeoxynivalenol (15ADON) chemotype, and the remainder were the NIV chemotype. FHB severity and trichothecene analysis indicated that F. asiaticum isolates with the 3ADON chemotype were more aggressive than those with the NIV chemotype in wheat. 3ADON and NIV chemotypes of F. asiaticum isolated from weeds and wheat showed no significant differences in pathogenicity in wheat. All selected F. asiaticum isolates produced perithecia, with little difference between the 3ADON and NIV chemotypes. These results highlight the epidemiology of the FGSC isolated from weeds near wheat fields, with implications for reducing FHB inoculum in China.

Weeding Frequencies Decreased Rice–Weed Competition and Increased Rice N Uptake in Organic Paddy Field

Different weeding frequencies (WFs)―0WF, 2WF, 4WF, 6WF, and 8WF―were adopted in an organic rice field to investigate their influence on weed types, rice and weed biomass, rice tiller and weed number, N concentration, and N uptake. The study field was located in Tsuruoka, Yamagata, Japan. Rice (cv. Sasanishiki) was planted from May to September 2019, and all weeding events were carried out until 49 days after transplantation (DAT) using a rotary weeder. Rice and weed samples were collected at 60, 88, and 110 DAT. Echinochloa crus-galli (E. crus-galli), Schoenoplectus juncoides, and Monochoria vaginalis (Burm. f.) were the most commonly found weeds. High weed diversity was observed at both 6WF and 8WF, E. crus-galli was the dominant weed at 0WF. Compared to 0WF, 2WF displayed a significantly decreased weed biomass. However, at 8WF, the weed biomass was reduced by 79.0%, the rice biomass was increased by 277%, and the rice tiller number was almost three times higher than that at 0WF and 110 DAT. Compared to 0WF, a significantly increased rice N uptake was observed at 4WF, and rice N uptakes achieved at 6WF and 8WF were two and four times higher than those at 0WF, respectively. Higher weeding frequencies provide notable benefits in suppressing weeds and supporting rice growth, especially in N uptake competition with weeds.

Evidence of expanded diversity in weeds as reservoir host of viruses in pepper fields across southwestern Nigeria

This study aimed to investigate virus occurrence in weed species in the main pepper-growing areas in Southwest Nigeria. The weed samples collected from pepper farms were identified and subjected to Antigen-Coated Plate Enzyme-Linked Immunosorbent Assay using antibodies specific eight different viruses. Results showed that the Weed species collected contain 17 families, 33 genera and 36 plant species of which 83.33% of the plant species tested positive to one or more plant viruses. The results indicate that potato virus Y (PVY) and potato virus X (PVX) infected more weed species (24). Also, Ageratum conyzoides serve as host to 8 viruses while Alchornea cordata, Corchorus olitoris and Talinum triangulare serve as host to 7 viruses respectively. These results provide information on weeds as virus reservoirs and contribute to the knowledge of epidemiology of these diseases, enabling a proper weed management aiming at reducing the secondary spreading control of viruses.

Identification of Weed Hosts of Tomato yellow leaf curl virus in Field-Grown Tomato in Sudan Savanna, Nigeria

This study is aimed to detect weed hosts of Tomato Yellow Leaf Curl Virus (TYLCV) in field-grown tomato (Solanum lycopersicum L.) in Sudan savanna regions (Gombe, Jigawa and Kano states) of Nigeria during 2017 and 2018 dry and wet seasons. Three farms each from three Local Government Areas (LGAs) of each state were surveyed. Ten symptomatic and asymptomatic weed samples within and around each farm (n=1080) were randomly collected and assayed against TYLCV using Triple Antibody Sandwich Enzyme-linked Immunosorbent Assay (TAS-ELISA). Based on the obtained results, 14 weed species from 12 families were detected as alternative host of TYLCV in all states surveyed but with variation in distribution. Gombe and Kano states had significantly (p ≤ 0.05) the highest number (7) of TYLCV weed hosts while the lowest number (4) of TYLCV weed hosts was recorded in Jigawa state. Cassia obtusifolia Linn., significantly (p ≤ 0.05) showed the highest TYLCV frequency rating of 12.1%. The study reports for the first time 13 weed species naturally occurring as an alternative host of TYLCV in Nigeria. The detection of these weed hosts of TYLCV will give a better understanding of the virus disease epidemiology for its effective management. Exploring more weed hosts of TYLCV and molecular characterization of the virus in these weeds for the possible evolution of novel strain(s) in the region is recommended.

A Survey of Five Plant Viruses in Weeds and Tobacco in Poland

Weeds may contribute to the spread of plant virus epidemics by acting as reservoirs of viruses or/and their vectors. The aim of this research was to study the prevalence of five viral pathogens in weeds in the fields of solanaceous crops in six provinces in Poland differing with soil and climate conditions. Most of the sampled sites were associated with tobacco production. The total number of 157 samples of tobacco and 600 samples of weeds were subjected to DAS-ELISA detection of tomato spotted wilt orthotospovirus (TSWV), cucumber mosaic virus (CMV), potato virus Y (PVY), tobacco mosaic virus (TMV) and tobacco ringspot virus (TRSV). Twenty nine percent of samples of weeds were infected with at least one virus. TSWV and TMV were the most frequently detected in 17.5% and 14.7% of samples, respectively. In most provinces where infected tobacco was found, the same virus was also detected in weeds. Results of this survey are discussed in the context of the current status of virus epidemics in tobacco fields in Poland.

​RCA-based Detection of Begomoviruses in Weed Genera Associated with Legumes in Southern Karnataka

Background: Yellow mosaic disease (YMD) caused by begomoviruses transmitted through the insect vector Bemisia tabaci poses a serious threat to the production of legume crops. Methods: Season-long surveys were carried out for YMD occurrence in six different legume crops and associated natural weeds both symptomatic and asymptomatic across the districts of southern Karnataka, India. The samples were analyzed through RCA PCR using specific primer pairs. Result: Up to 94.1 per cent YMD incidence was recorded and nine weed species were commonly found associated with legume crops. The weeds viz., Ageratum conyzoides, Alternanthera sessilis, Commelina benghalensis and Euphorbia geniculata were abundantly found in the surveyed regions. The weeds were both symptomatic and asymptomatic. Rolling circle amplification coupled polymerase chain reaction method was employed to detect yellow mosaic virus in asymptomatic weeds. Phylogenetic analysis based on the sequences of PCR amplified products of weeds and symptomatic legumes revealed a close clustering of the weed samples with horsegram yellow mosaic virus, legume yellow mosaic virus and mungbean yellow mosaic virus. Overall, our data suggests the role of weed species associated with legume crops as alternative/collateral hosts of begomoviruses and their role in the epidemiology of yellow mosaic disease.

​RCA-based Detection of Begomoviruses in Weed Genera Associated with Legumes in Southern Karnataka

Background: Yellow mosaic disease (YMD) caused by begomoviruses transmitted through the insect vector Bemisia tabaci poses a serious threat to the production of legume crops. Methods: Season-long surveys were carried out for YMD occurrence in six different legume crops and associated natural weeds both symptomatic and asymptomatic across the districts of southern Karnataka, India. The samples were analyzed through RCA PCR using specific primer pairs. Result: Up to 94.1 per cent YMD incidence was recorded and nine weed species were commonly found associated with legume crops. The weeds viz., Ageratum conyzoides, Alternanthera sessilis, Commelina benghalensis and Euphorbia geniculata were abundantly found in the surveyed regions. The weeds were both symptomatic and asymptomatic. Rolling circle amplification coupled polymerase chain reaction method was employed to detect yellow mosaic virus in asymptomatic weeds. Phylogenetic analysis based on the sequences of PCR amplified products of weeds and symptomatic legumes revealed a close clustering of the weed samples with horsegram yellow mosaic virus, legume yellow mosaic virus and mungbean yellow mosaic virus. Overall, our data suggests the role of weed species associated with legume crops as alternative/collateral hosts of begomoviruses and their role in the epidemiology of yellow mosaic disease.

Weeds e-Catalog as a Tool for Identification of Weeds in Plantation

Weeds are one of the organisms that interfere with plant growth. Information about the identity of weeds becomes very important on plantations. Although weeds data digitization has been done a lot, currently there is still not much weeds data information system can be accessed online. Weeds management is often dealt with weeds herbarium or weeds photographs.In an effort to provide a good information system for farmers, this research aims to create a database of various types of weeds and an information system that can be accessed online. The methodology for developing a weed catalog information system uses the Software Development Life Cycle (SDLC). Weed samples in database were collected through systematic random sampling in the form of images and text. The result of this study is a Weeds Electronic Catalog or Weeds e-Catalog that can facilitate the information of weeds identity such as names, classifications, morphology, life cycles, and habitats of various types of weeds that grow on plantation land. Weeds e-Catalog can be used by plantation practitioners and farmers to make decisions in controlling weeds.

Morphological diversity in purple nutsedge from four agro-ecological zones in Ghana

Purple nutsedge (Cyperus rotundus L.) exhibits plasticity and are morphologically different under different conditions. Due to these differences, the weed might respond differently to weed management. Here, we examined the morphological characteristics of purple nutsedge from southern Ghana relative to those reported from other countries and further assessed differences in ecotypes from four agro-ecological zones in Ghana. A total of 46 purple nutsedge samples: 40 samples from 40 communities across the study area and three each from two research stations were used for the study. The plants were multiplied, planted into pots and laid out in Completely Randomized Design with three replications. Qualitative and quantitative assessments were carried out on both underground and aboveground morphological traits of the weed samples. The qualitative traits of the samples generally conformed to those reported in other countries and did not vary significantly between the agro-ecological zones (P > 0.05). The quantitative (growth) parameters showed significant differences among agro-ecological zones (P < 0.05) and were generally smaller than those reported in other countries, suggesting morphological adaptation of the weed in Ghana. Samples from the transitional zone were significantly smaller and this could facilitate easier management of the weed in that area. The principal component analysis gave four latent factors, which mainly pointed to photosynthetic structures and growth characteristics as the major components determining variations in the collection. Cluster analysis gave four clusters (at 0.7 similarity index), which were related neither to their geographic origin nor to the agro-ecological zones.

Design and development of a servo-controlled target-oriented robotic micro-dose spraying system in precision weed control

The broadcast spraying method using excessive amounts of pesticides is generally preferred for weed control in agriculture. In this study, a mobile robot was developed and tested on artificial weed targets for a micro-dose spraying system to reduce amount of liquid sprayed for weed control. A prototype mobile robot consisting of a robotic platform, machine vision and steerable spraying unit was constructed and controlled by using LabVIEW software and tested to evaluate the applicability of the spraying system. The greenness method and segmentation algorithm were used to extract artificial weeds from the background. The artificial weed samples were treated according to their coordinates by using a servo-based micro-dose spraying needle nozzle. The experiments were carried out at speeds of 0.42, 0.54, 0.66, 0.78 and 0.90 km h-1 to evaluate the performance of the spraying system under laboratory conditions. The tracking and targeting performances of the mobile spraying system were observed visually. Consumption, deposition and coverage rate experiments were carried out by using graduated cups, filter papers and water-sensitive papers to evaluate the spraying efficiency of the system under 200 kPa of spraying pressure. The results showed that the targeted micro-dose spraying method saved approximately 95% of the application volume compared with the broadcast spraying method. Higher spraying efficiency was determined at the middle locations rather than at the edge locations according to the amount of deposition and coverage rate results. The servo-controlled target-oriented weed control system that was developed was tested experimentally and found to be very efficient.

Do detection dogs respond differently to dried, frozen and live plant targets?

Weeds can have detrimental impacts on agriculture and the environment, and effective detection of individual plants is a crucial component of weed management. An emerging detection tool is the use of dogs (Canis familiaris) trained to recognise a weed’s scent. Scent-detection dogs are well established as a tool in other disciplines but deploying dogs within weed management poses novel challenges. It can be difficult (or even illegal) to source a large number of live target weeds for training and evaluation purposes, due to the risk that these targets will create further detrimental impacts. We investigate whether invasive weed samples could be processed into inert and therefore bio secure dried or frozen forms for use in training. There is currently limited understanding of whether training dogs on frozen or dried plant targets can transfer into successful detection of the live target. We trained four dogs to detect frozen plant samples and four dogs to detect dried plant samples and exposed all eight dogs to scent boards containing frozen, dried and/or live plant targets.All dogs detected the three target types with high precision (100 %) and sensitivity (>85 %). Only one dog showed a statistically significant preference for the frozen odour. Our findings support the use of frozen and dried plant matter as an effective training and evaluation tool for dogs, in cases where the live target cannot be safely used at a broad scale.

Identification of Weeds Based on Hyperspectral Imaging and Machine Learning.

Weeds can be major environmental and economic burdens in New Zealand. Traditional methods of weed control including manual and chemical approaches can be time consuming and costly. Some chemical herbicides may have negative environmental and human health impacts. One of the proposed important steps for providing alternatives to these traditional approaches is the automated identification and mapping of weeds. We used hyperspectral imaging data and machine learning to explore the possibility of fast, accurate and automated discrimination of weeds in pastures where ryegrass and clovers are the sown species. Hyperspectral images from two grasses (Setaria pumila [yellow bristle grass] and Stipa arundinacea [wind grass]) and two broad leaf weed species (Ranunculus acris [giant buttercup] and Cirsium arvense [Californian thistle]) were acquired and pre-processed using the standard normal variate method. We trained three classification models, namely partial least squares-discriminant analysis, support vector machine, and Multilayer Perceptron (MLP) using whole plant averaged (Av) spectra and superpixels (Sp) averaged spectra from each weed sample. All three classification models showed repeatable identification of four weeds using both Av and Sp spectra with a range of overall accuracy of 70–100%. However, MLP based on the Sp method produced the most reliable and robust prediction result (89.1% accuracy). Four significant spectral regions were found as highly informative for characterizing the four weed species and could form the basis for a rapid and efficient methodology for identifying weeds in ryegrass/clover pastures.

Influence of periods of coexistence of weeds on organic okra production

Weed management in okra grown in organic system minimizes crop yield losses. Thus, the objective of this study was to determine the period prior to weed interference in okra grown in organic system during the rainy and dry seasons in the state of Maranhão, northeastern Brazil. Experiments were conducted in the rainy and dry seasons in randomized block design with seven treatments and four replications. The treatments were T1 = weeds coexistence with okra for 7 days; T2 = coexistence for 14 days; T3 = coexistence for 21 days; T4 = coexistence for 28 days; T5 = coexistence for 35 days; T6 = coexistence for 42 days and, T7 = coexistence for 74 days). In addition to these treatments, we kept a control treatment with weed free until harvest to obtain maximum yield. At the end of each period of weed coexistence with the crop, three weed samples were collected in 0.25 m² to evaluate density, dry mass and to analise phytosociological parameters. The main weeds in both seasons were Commelina benghalensis, Cynodon dactylon, Eleusine indica, Alternanthera tenella and Amaranthus spinosus. The coexistence of weeds with the crop until harvest caused losses of 51% in the rainy season and 67% in the dry season compared to weed free control. In the rainy season, the period before weed interference (PBI) on okra crop of organic system was 12 days after emergence (DAE). In the dry season, 5% yield loss was observed 4 days after transplanting (DAT). Weed management in organic okra should be carried out earlier in the dry season than in the rainy season to avoid high yield losses

Morphological, Pathological, Biochemical and Molecular Characterization of &amp;lt;i&amp;gt;Ralstonia solanacearum&amp;lt;/i&amp;gt; Isolates in Bangladesh

One thirty samples (fifty-five potato tubers, twenty-seven potato stems, three chili stems, twenty-eight soil samples, five weed samples, three banana leaves, and nine water samples) were examined and one hundred six (106) Bangladeshi isolates of Ralstonia solanacearum were isolated and identified. Isolation was made on selective media (Tetrazolium chloride media) and R. solanacearum was identified based on morphological, pathological and biochemical properties and polymerase chain reaction (PCR) by using the species-specific primers. Studies showed that 81.54% (106) samples were positive on tetrazolium chloride solid medium. Among them 90 isolates were virulent and rest of them were avirulent. Fifty isolates were selected for chemical characterization based on hypersensitivity test. R. solanacearum is gram negative, aerobic facultative bacteria on the basis of chemical characterization. Fifty tested isolates expressed as race 3 while in biovar test forty-eight showed as biovar III and the rest two showed as biovar I. In nine tested isolates from the three districts a species-specific band of 280 bp was amplified in PCR that confirmed the identity of R. solanacerum.

‘Candidatus Phytoplasma australasia’ association with phyllody andpurpling diseases of carrot in India

Carrot plants showing suspected phytoplasma symptoms of witches’ broom and purpling at IARI fields, New Delhi and Kushmi Jungle, Gorakhpur, Uttar Pradesh were subjected to nested PCR assay on 16S rRNA and secA genes with specific primer pairs. Amplification of 1.25 kb and 480 bp was achieved from all the symptomatic samples collected from Gorakhpur and New Delhi using 16S rRNA and secA gene primers, respectively. Hshimonus phycitis from Gorakhpur and Empoasca motti from New Delhi and Cannabis sativa and Parthenium hysterophorus in and around carrot fields at Delhi and Kushmi Jungle, Gorakhpur were also detected positive for phytoplasma presence by employing both set of primers. The 16S rRNA and secA gene sequences and virtual RFLP comparison analyses confirmed the presence of ‘Candidatus Phytoplasma australasia’ (16SrII-D) in carrot, leafhoppers and weed samples. This is the first report of the presence of this phytoplasma associated with witches’ broom and purpling disease of carrot in Northern India.

Planococcus spp.: behavior and monitoring in conilon coffee crops

The damage caused by the citrus mealybug attack on Coffea canephora crops is becoming more and more frequent, and may cause losses close to 100%. Knowledge of aspects related to pest behavior and adoption of methods to monitor crop incidence are important tools for integrated pest management. Thus, the objective was to study the behavior of citrus mealybug along the phenological stages of C. canephora and to propose methods to monitor its occurrence in the crops. The study was carried out in an area consisting of adult C. canephora plants of the variety Diamante ES 8112. The study was carried out using four sampling methods: 1) soil and root sampling with a probe; 2) opening small trenches; 3) plagiotropic branches and 4) weed sampling. Evaluations were carried out monthly by checking and confirming the presence of citrus mealybug in the sampled regions. The information obtained was used to describe the behavior of citrus mealybug and to analyze the applicability of the monitoring methods studied. In the absence of the reproductive phase, citrus mealybug lodges in the root system of coffee and weeds, in the region close to the colon, moving to the aerial part of the plants (rosettes) at the beginning of the flowering of the crop. Probe sampling was not efficient, while opening small trenches is a difficult procedure and causes damage to the root system of the coffee tree. The sampling of plagiotropic branches and weeds allows the monitoring of citrus cochineal during all the phenological phases of C. canephora. Key words: Coffea canephora; Integrated pest management; Citrus mealybugs; Sampling; Weeds.

Isolation of pathogens from leaf, root and rhizosphere water samples of aquatic weeds, Eichhornia crassipes and Pistia stratiotes present in the backwaters of YMCA canal, Alappuzha, Kerala, India

The presence of pathogenic microorganisms in backwaters is of a great concern and the unsafe water is responsible for 1.2 million deaths each year. In the present study, water samples beneath the aquatic weeds, leaf and root samples of E. crassipes and P. stratiotes were collected from YMCA canal, Alappuzha, Kerala state, India, and subjected to physicochemical and microbiological analysis. The pH of the water samples were in the range of 6.6 to 6.9, salinity was nil, electrical conductivity was 5.327 mS for Eichhornia crassipes sample and 882.2 mS for Pistia stratiotes rhizosphere water sample. Total dissolved solids (TDS) were 2.777 ppm and 448 ppm for E. crassipes and P. stratiotes respectively. Heterophilic plate count of E. crassipes is 11 x 103 and 3 x 102 CFU/ml for bacteria and fungi respectively. Similarly the rhizosphere water sample of P. stratiotes showed a bacterial count of 75 × 103 CFU/ml and the fungal count was 8 x 102 CFU/ml. Human pathogens such as Klebsiella. pneumoniae, Salmonella typhi, Enterococcus faecalis, E. coli, Vibrio cholerae, Salmonella enteritidis, Enterobacter aerogenes, Vibrio vulnificus etc. were isolated from leaf, root and rhizosphere water samples. Antibiotic sensitivity studies revealed that Klebsiella pneumoniae was resistant to antibiotics like Azithromycin, Co-Trimoxazole, Cefuroxime and Cefalexin. Most of the pathogens were resistant to Cefalexin.

Distribution, Severity Status, Farmers Knowledge and Management Practices of Wild Radish (Raphanus raphanistrum L.) in Horro Guduru Wollega Zone, Western Ethiopia

The objective of the study was to study the distribution, severity status, farmers’ knowledge, impacts and management practices of Wild Radish (Raphanus raphanistrum L.) in Horro Guduru Wollega Zone, Western Ethiopia. The collected data were analyzed by using descriptive statistics. The Shannon Diversity Index (SDI), the evenness, species richness and Jaccards Similarity Index (JSI) was calculated from the recorded weed samples. Correlation of vegetation variables among and between sampled Administrative Kebeles’ was analyzed by SPSSv20 software. The result of the study indicates that out of the sampled 160 respondents 92 (57.5%) of them heard about wild radish plant as a weed and the rest of 68 (42.5%) of the respondents did not know this plant as a weed. Among the respondents 88 (55%) of them identify R.raphanistrum plant as a weed. There was high negative correlation between mean R. raphanistrium density and Shannon diversity index with R 2 = 0.642, p&lt;0.001. This study showed that high infestation level of R . raphanistrum was observed in Horro district followed by Abayi Chomen, Amuru and Jima Rare districts. The highest and lowest mean population (±SD) of R. raphanistrum per quadrate was recorded at Horo (249.82 ± 34.67) and Jima Rare (13.72 ± 14.16), respectively. The biodiversity impact of R. raphanistrium at highly infested areas were more visible than the moderately infested areas. Horro and Abayi Chomen districts showed the lowest Shannon Diversity Index value of 1.78 and 2.12, respectively, due to the fact that, their species diversity was highly affected by the high population density of R. raphanistrium. Moreover, the standing herbaceous vegetation from the sampled sites of Horo district (Doyo Bariso and Gudina Abuna administrative kebeles) showed higher Jaccards Similarity coefficient (0.84), where there was high R.raphanistrium infestation level. The study proved that R. raphanistrum was emerged as invasive weed and have been disseminated into neighbor districts’ and zones. Therefore, further research should be conducted to quantify the distribution, increases in species abundance as well as its impact on biodiversity and socio-economic aspects, which may support to contain R. raphanistrum distribution and planning on its prevention and management. Keywords: Abundance, distribution, invasive , Raphanus raphanistrum, severity, wald radish DOI: 10.7176/JBAH/10-24-02 Publication date: December 31 st 2020