Ludwigia Hyssopifolia Research Articles

A comparative study of DPPH radical scavenging property and antiproliferative potential on human hepatic cancer (HepG2) cells of methanolic extracts from different parts of <i>Ludwigia hyssopifolia</i> and <i>Ludwigia adscendens</i>

Ludwigia hyssopifolia and Ludwigia adscendens are two indigenous and common plant species in Vietnam with hepatoprotective property mentioned in numerous articles published in international journals. Therefore, the current paper aimed to evaluate the physicochemical parameters, total polyphenolic and flavonoid contents of the methanolic extracts from 04 parts of Ludwigia hyssopifolia and Ludwigia adscendens in Mekong delta, Vietnam. Most importantly, antioxidant properties by DPPH radial scavenging assay and antiproliferative potentials on human hepatic cancer (HepG2) cells of these multiple extracts also were determined in the in vitro models. These results showed that physicochemical parameters were within allowable limits according to the literatures. Among the investigated samples, the leaf and whole plant extract from Ludwigia hyssopifolia had the highest values of total phenolic and flavonoid contents being 196.55 ± 5.05 mg GAE/g and 64.72 ± 4.63 mg QE/g respectively. Additionally, the methanol whole plant extract of Ludwigia hyssopifolia and the methanol leaf extract of Ludwigia adscendens show the greatest antioxidant properties in DPPH scavenging assay with IC50 values of 44.48 ± 4.29 µg/mL and 26.11 ± 0.37 µg/mL respectively. Furthermore, the methanolic extract from Ludwigia hyssopifolia leaves displays the most potential anti-HepG2 activity among all surveyed samples. Therefore, the most promising extracts need further evaluation for potential herbal product developments.

Evaluating antibacterial efficacy of extracts from Ludwigia hyssopifolia against pathogenic bacteria

Ludwigia hyssopifolia extracts have historically been consumed as a healthful drink and rich in biomass. Therefore, the aims of this study were to determine the most effective fractionated extracts of L. hyssopifolia against pathogens. The whole plants of L. hyssopifolia were extracted various fractions with methanol, hexane, chloroform, ethyl acetate, and aqueous. The total phenolics and flavonoids was screened using quantitative approaches. The extracts tested for antibacterial activity against pathogens, including Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella Typhi, and Helicobacter pylori through the agar diffusion technique and the microtiter broth dilution method. The largest yield was obtained from the aqueous fractional extract. The phytochemical composition discovered in ethyl acetate was more abundant in phenolics and flavonoid compounds. Fractionation enhanced the antibacterial effect of the extract. The extracts showed a broad spectrum of antibacterial activity against all the bacteria tested, particularly H. pylori. In parallel, ethyl acetate extract showed antibacterial activity. The current results could provide rational support for the traditional use of L. hyssopifolia to treat infectious diseases and provide data for developing natural products.

Comparative genomics revealed new insights into the plastome evolution of Ludwigia (Onagraceae, Myrtales).

The primrose-willow (Ludwigia L.), a well-defined genus of the Onagraceae family, comprises 87 species widely distributed worldwide. In this study, we sequenced and characterized the complete chloroplast (cp) genomes of three species in the genus, including Ludwigia adscendens, Ludwigia hyssopifolia, and Ludwigia prostrata. Three Ludwigia cp genomes ranged from 158,354 to 159,592 bp in size, and each contained 113 genes, including 79 unique protein-coding genes (PCGs), four rRNA genes, and 30 tRNA genes. A comparison of the Ludwigia cp genomes revealed that they were highly conserved in gene composition, gene orientation, and GC content. Moreover, we compared the structure of cp genomes and reconstructed phylogenetic relationships with related species in the Onagraceae family. Regarding contraction/expansion of inverted repeat (IR) region, two kinds of expansion IR region structures were found in Oenothera, Chamaenerion, and Epilobium genera, with primitive IR structures in Ludwigia and Circeae genera. The regions clpP, ycf2, and ycf1 genes possessed highly divergent nucleotides among all available cp genomes of the Onagraceae family. The phylogenetic reconstruction using 79 PCGs from 39 Onagraceae cp genomes inferred that Ludwigia (including L. adscendens, L. hyssopifolia, L. prostrata, and Ludwigia octovalvis) clade was monophyletic and well-supported by the bootstrap and posterior probability values. This study provides the reference cp genomes of three Ludwigia species, which can be used for species identification and phylogenetic reconstruction of Ludwigia and Onagraceae taxa.

Uptake and translocation of lead and cadmium in wild-found plant species from Bekasi and Karawang, West Java, for phytoremediation

Environmental degradation due to lead (Pb) and cadmium (Cd) pollution has been increasing. One of the alternative cost-effective green technologies to clean up heavy metal contamination is phytoremediation. This research aims to determine the potential of wild-found plants that could be used as Pb and Cd bioaccumulators. Plant species in this study were collected from heavy metal-contaminated soil in Bekasi and Karawang, West Java. Five species, namely Saccharum spontaneum, Acorus calamus, Ipomoea fistulosa, Ludwigia hyssopifolia, and Eichhornia crassipes, were studied for Pb accumulation capacity. Furthermore, five plant species, namely Limnocharis flava, Colocasia esculenta, Ipomoea fistulosa, Commelina benghalensis, and Eichhornia crassipes, were studied for their Cd accumulation capacity. The experiment was done in a greenhouse for eight weeks. Pb and Cd concentration were analyzed using atomic absorption spectrometry (AAS) to determine the uptake and translocation of Pb or Cd. I. fistulosa accumulated the highest amount of Pb, with a growth rate of up to 27.07 g week−1, a bioconcentration factor (BCF) of 1.46, and a translocation factor (TF) of 0.87 upon 300 mg kg−1 Pb treatment. C. esculenta showed considerable Cd bioaccumulation, as indicated by a BCF of 0.95 and a TF of 0.65, accompanied by sustained relative biomass increase (124.9%) and the highest growth rate (36.96 g week−1) among tested plant species upon 75 mg kg−1 Cd treatment. With their capacities for bioaccumulating Pb and Cd, respectively, I. fistulosa and C. esculenta were identified as potential accumulator species for phytoremediation in heavy metal-contaminated sites such as former mining lands, landfills, and highly polluted agricultural lands.

In Vitro Antibacterial Activity of Tropical Plant Extracts Against Fish Pathogens in Vietnam

Crude methanol extracts of 43 Vietnamese plants were screened in vitro for their antibacterial activity against three common freshwater fish pathogens, including Aeromonas hydrophila, Edwardsiella ictaluri and Streptococcus agalactiae. The agar disc diffusion method was used to evaluate the antibacterial activity, followed by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined using the broth dilution method. Among the 43 plants screened, eight plant extracts (Bouea oppositifolia, Wedelia chinensis, Terminalia catappa, Punica granatum, Sonneratia caseolaris, Sonneratia ovata, Ludwigia hyssopifolia and Phyllanthus urinaria) exhibited wide-spectrum antibacterial activity to all three common freshwater fish pathogens. Six plant extracts (Ageratum conyzoides, Alpinia galanga, Borassus flabellifer, Abutilon indicum, Eupatorium odotatum, and Scoparia dulcis) might be good candidates for the prevention of co-infection of E. ictaluri and S. agalactiae in tilapia whereas Muntingia calabura and Camellia sinensis could be applied to striped catfish to combat E. ictaluri and A. hydrophila. Through MIC and MBC determination, L. hyssopifolia, A. galanga, Ageratum conyzoides extracts showed a bactericidal activity to A. hydrophila, E. ictuluri and S. agalactiae, respectively, while the other extracts could prevent the growth of tested bacteria. The screening results suggested the potential application of plant extracts as alternative therapeutic agents against bacterial infections in aquaculture.

Keanekaragaman Echinodermata Di Pantai Desa Pakowa Bunta Kecamatan Nuhon Kabupaten Banggai

Forests are one of the natural resources that has an important and potential role for human life, therefore it is necessary to preserve their existence as a function to support living systems. The objective of this research is to know how to make an inventory of plant species belonging to Family Asteraceae in Batu Tikar Forest, Luwuk District, Banggai Regency. This type of research is descriptive research. Researchers seek, collect, describe, and interpret research data found in the field systematically, factually, and accurately. This research was conducted in August 2020. Sampling was carried out by the exploration method, namely tracing the research area. It is Batu Tikar forest. The data obtained from the research results were then analyzed descriptively qualitatively. The results of this study found 9 species, namely Chromolaena odorata, Eclipta prostrata, Synedrella nodiflora, Ageratum Conyzoides, Tridax procumbens, Cyanthillum cinereum, Ludwigia hyssopifolia, Acmella paniculata and Bidens pilosad with a total of 39 individuals. From the research results, it can be seen that the plants of the asteraceae family belong to 9 genera, namely Chromolaena, Eclipta, Synedrella, Ageratum, Tridax, Cyanthillum, Ludwigia, Acmella and Bidens.
 
 Keywords: Batu Tikar Forest, Asteraceae Family, Inventory

Inventarisasi Famili Asteraceae di Hutan Batu Tikar Kecamatan Luwuk Kabupaten Banggai

Forests are one of the natural resources that has an important and potential role for human life, therefore it is necessary to preserve their existence as a function to support living systems. The objective of this research is to know how to make an inventory of plant species belonging to Family Asteraceae in Batu Tikar Forest, Luwuk District, Banggai Regency. This type of research is descriptive research. Researchers seek, collect, describe, and interpret research data found in the field systematically, factually, and accurately. This research was conducted in August 2020. Sampling was carried out by the exploration method, namely tracing the research area. It is Batu Tikar forest. The data obtained from the research results were then analyzed descriptively qualitatively. The results of this study found 9 species, namely Chromolaena odorata, Eclipta prostrata, Synedrella nodiflora, Ageratum Conyzoides, Tridax procumbens, Cyanthillum cinereum, Ludwigia hyssopifolia, Acmella paniculata and Bidens pilosad with a total of 39 individuals. From the research results, it can be seen that the plants of the asteraceae family belong to 9 genera, namely Chromolaena, Eclipta, Synedrella, Ageratum, Tridax, Cyanthillum, Ludwigia, Acmella and Bidens.
 
 Keywords: Batu Tikar Forest, Asteraceae Family, Inventory

Weed diversity in rice (Oryza sativa) fields with different cultivation technologies in Garut Regency, Indonesia

The presence of weeds in lowland rice cultivation will result in reduced growth and yield of rice plants, so the presence of weeds in cultivated crops must be controlled. Weed control applied to lowland rice cultivation will run effectively and efficiently after knowing the diversity of dominant weeds present in lowland rice cultivation. This study was conducted during 2017–18 at Padjadjaran University, Bandung, Indonesia to determine the diversity of weeds in lowland rice cultivation, both on conventional and SRI technology. The research was conducted on rice fields owned by farmers in four sub-districts in Garut Regency. The method used in this research is non-experimental through the survey method. Sampling was carried out on paddy fields using conventional planting system technology and SRI, each of 42 plots with a quadrant of 0.5 m x 0.5 m spread over four districts. The results showed that the types of weeds found in the conventional system were 20 types of weeds with the dominant weed Ludwigia hyssopifolia, in the SRI system there were 17 types of weeds with the dominant weed of Echinocloa crus-galli. The value of the diversity index (diversity) of weed species found in lowland rice cultivation in the Garut Regency area both in the conventional system and the SRI system is classified as moderate. The distribution pattern of all types of spatial weeds in lowland rice cultivation in the Garut Regency area, both in the conventional system and the SRI system, is included in the group distribution pattern.

Sifat Campuran Herbisida Berbahan Aktif Bentazon dan MCPA Terhadap Gulma Daun Lebar, Teki dan Rumput

<p>Weed control using a single herbicide with same active ingredients can add the risk of weed resistance. Using mixed herbicides can increase the spectrum of weeds controlled, and inhibit weed resistance. Herbicide mixture with two or more types of active ingredients will show the interactions between one and another ingredient. These interactions could be synergistic, antagonistic, and additive. The research was to determine the response of mixed herbicide Bentazon, MCPA 460 g. L⁻¹ and their mixed characteristic. This experiment was conducted from June until August 2019 in the greenhouse at the Faculty of Agriculture, Universitas Padjadjaran. The treatment consisted of three types of herbicides with six dose levels, namely a single herbicide of Bentazon 400 g. L⁻¹ and MCPA 60 g. L⁻¹ (4; 2; 1; 0.5; 0.25; 0 L.ha⁻¹), a mixed herbicide Bentazon MCPA 460 g.L⁻¹ (5; 2.5; 1.25; 0.625; 0.3215; 0 L.ha⁻¹) with four replications. The target weeds tested were <em>Spenochlea zeylanica</em>, <em>Ludwigia hyssopifolia</em>, <em>Fimbristylis miliacea</em>, and <em>Cyperus iria</em> was taken from the Ciparay area. Data were analysed by linear regression analysis and multiplicative survival model (MSM) method to determine the LD50 treatment and expectation. The result showed that compound herbicides of Bentazon and MCPA LD50 treatment (0,3857 g.ha⁻¹) had smaller value than LD50 expectation (0,6943 g.ha⁻¹) with a ecotoxicity value of 1.8 (> 1), so that the herbicide mixture was synergistic.</p>

Weed Survey in Different Fields of Transplanted Rice (Oryza sativa L.) in North Pulinpur Area under Khowai District of Tripura

The present investigation was carried out during kharif season 2017-18 at North Pulinpur area under Khowai district, Tripura (23°52.836′ N, latitude of 91°35.275′ E, longitude, and 940 m above sea level). North Pulinpur is one of the drought prone areas of Khowai district, Tripura. The area falls under the subtropical hill zone, and the climate is humid. An average annual rainfall ranges from 2050-2550 mm. The soil of the experimental field was sandy loam in texture acidic in reaction with a soil pH of 4.5-5.8 and medium in fertility status with low water holding capacity. Rice field surveyed covering 435 fields of four villages (V-I, II, III and IV) the number of respective field was 102, 141, 75 and 117, respectively. Weeds indicated there were 42 species belonging to 20 families of which 22 species were broad-leaved, 10 grasses, 7 sedges and 3 aquatics. Species diversity ranking of weed community for the villages were Village-II>Village-III>Village-I>Village-IV.  Based on Sorenson’s Index of Similarity of the S value is 87.67-102.77 %. The highest S value of 102.77% was between Village-I and Village-III, while the lowest value of 87.67% between Village-II and Village-IV. The higher S value indicated that species composition between villages was closely similar and the lower S value indicated species compositions in both villages were diverse. Out of 42 weed species, six species namely Oryza sativa (Weedy rice) followed by Echinochloa crus-galli, Leptochloa chinensis, Cynodon dactylon, Ludwigia hyssopifolia, Fimbristylis milacea were most abundant in all villages with a greater proportion of severe infestation (score of 5:41-50 % weed cover).

BIOMETHANE POTENTIAL OF INVASIVE AQUATIC WEED WATER PRIMROSE

This study aims to examine the perspective of feedstock for producing biomethane from invasive aquatic weed water primroses (Ludwigia Hyssopifolia). The methane yield and methane content of biogas were analyzed and studied. The calculating methods of theoretical methane yield based on the elemental application or the theoretical chemical oxygen demand (COD) number were showed. The percentage of element chemicals, carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S) of raw materials were analyzed, and results were 40.2%, 5.03%, 22.13%, 1.8% and 0.24%, respectively. The plant biomass was contained moisture content, volatile carbon, fixed carbon and ash were 7.28%, 63.07%, 1.28% and 28.37%, respectively. From the water primroses calculated yield of methane (CH4), carbon dioxide (CO2) and ammonia (NH3) results were 54.90%, 41.40% and 3.70%, respectively. Therefore, the aquatic weed water primroses biomass are suitable feedstock for biogas production as well as future scale-up studies.

Morphological, anatomical and phytochemical properties of (Ludwigia hyssopifolia (G. Don) Exell) at Can Tho province, Vietnam

The objectives of the study were to investigate the botanical characteristics and determinate the natural compounds in aerial part and root extracts of Ludwigia hyssopifolia (G. Don) Exell in CanTho province. Double staining with carmine-iodine green was used for anatomical examination, hypo-osmotic shock method was used to estimate chromosome numbers, and the phytochemical components were determined by using reagents and standards. The results showed the morphological and anatomical characteristics of L. hyssopifolia leaf, stem, and root. The chromosome number were estimated (2n = 16). Aerial part and root extracts showed the presence of saponins, flavonoids, tannins, glycosides, alkaloids, steroids, phenolics, coumarins, and terpenoids. No terpenoids was detected at both aerial part, and root extracts. At aerial part, the total phenolic, tannins, and flavonoid contents were respectively 126.8±28 mg gallic acid /g dry weight of the extract, 116.2 ± 18 mg gallic acid/g dry extract, and 242.3 ± 23 mg quercetin/g dry extract. At root, the total phenolic, tannins, and flavonoid contents were 45.5 ± 11 mg gallic acid/g dry extract, 54.8 ± 23 g gallic acid/g dry extract, and 58.6 ± 2.4 mg quercetin/g dry extract respectively.

A pair of new isocoumarin enantiomers of Ludwigia hyssopifolia

A pair of new isocoumarin derivative enantiomers, (S)-(-)-3-(3,3-dichloro-2-hydroxy-propyl)-4-chlorine-6,8-dihydroxy-isochromen-1- one (1a) and (R)-(+)-3-(3,3-dichloro-2-hydroxy-propyl)-4-chlorine-6,8-dihydroxy-isochromen-1- one (1 b), as well as seven known compounds (2–8) were isolated from Ludwigia hyssopifolia. Compounds 1a and 1 b were confirmed to be a pair of enantiomers by chiral HPLC-CD analysis, and the structure of compound 1 was determined by spectroscopic analyses including extensive 1 D (1H NMR, 13C NMR) and 2 D NMR spectra (COSY, HSQC and HMBC) and MS data. And the absolute configurations of compounds 1a and 1 b were determined by the quantum chemical ECD calculations. Compounds 2–8 are firstly reported from this plant. In the in vitro assays, compounds 5 and 8 can inhibit human laryngeal cancer Hep-2 cell line growth in a dose- and time-dependent manner. In addition, compounds 2 and 4 have effects on increasing glucose uptake in vitro. Compound 2 showed a strong glucose uptake in L6 cells, with enhancements by 1.8 folds.

Nutritional values of swamp grasses as feed for Pampangan Buffaloes in South Sumatra, Indonesia

Abstract. Muhakka, Suwignyo RA, Budianta D, Yakup. 2020. Nutritional values of swamp grasses as feed for Pampangan Buffaloes in South Sumatra, Indonesia. Biodiversitas 21: 953-961. This study was aimed at determining the types and quality of vegetation in the swamp area, which could be used as sources of roughage for Pampangan buffaloes in South Sumatra. In this descriptive study, Results showed that the highest crude protein and ether extract contents, 20.56 and 2.92%, respectively, were found in (Neptunia oleracea). The highest ash content of 25.19% was found in Cyperus digitatus. The lowest fiber content (11.01%) was found in Ludwigia hyssopifolia, which also had the lowest content of Neutral Detergent Fiber (NDF) (40.64%). Hemicellulose content was found to be highest (37.14%) in Leersia hexandra. The lowest ADF (23.66%) and lignin (14,84%) contents were found in Nymphaea lotus. N. oleracea was found to have the lowest content (27.08%) of cellulose. It was concluded that the swamp vegetation found in this study consisted of 17 species of grasses and herbs (89.47%) and two species of legumes (10.53%). C. digitatus and L. hyssopifolia were found to have the best nutritional values. Dominant and palatable vegetation with good nutritional values, which were potential to be used as sources of roughage for Pampangan buffaloes, were Hymenachne acutigluma, Oryza rufipogon, Hymenachne amplexicaulis, Polygonum barbatum, and Eleocharis dulcis.

Studi Pengetahuan Masyarakat Mengenai Gulma Air Sebagai Bioindikator Pencemaran Air Di Desa Lambur Luar Kabupaten Tanjung Jabung Timur

The number of aquatic plants along the river flow outside the village of Lambur becomes a barrier to water traffic so that these plants are classified to be weeds or a nuisance for local people. This study aims to determine and document the types of weeds found in the village of Lambur and explore locals’ knowledge about the types of existing water weeds and their use. This research was conducted in the Village of Lambur Luar Tanjung Jabung Timur District by using the roaming method to collect existing Weed samples. Data collection is done by observation, interviews, documentation and literature studies, the data are analysed descriptive qualitative design. The results showed that there were 19 species and 13 families of water weeds, namely: Fimbristylis sp1, fimbristylis sp2, Cyperus sphacelatus Rottb, Blyxa aubertii Rich, Lindernia sp, Glinus oppositifolius (L.) Aug.DC, Melastoma malabathticum L, Nymphaea nouchali Burn, Ludwigia hyssopifolia (G.Don) Exell, Ludwigia repens JR Forst, Scoparia dulcis, Hippochaete debilis (Roxb.ex Vaucher) Ching, Panicum repens L, Oryza sativa, Persicaria hydropiper L, Monochoria vaginalis (Burm.f.) C.Presl, Borreria alata (Aubl.) DC, Borreria repens DC, and Xyris sp. Of the 19 species found, only 12 species, the locals know the name of the water weed, 7 species are only referred to as grass only by the locals, this water weed is not used by the them but mostly weeds are used for animal feed, the researchers provide education to the community that actually weed water can be used for treatment and to find out the quality of a waters or be used as an indicator of the biological condition of a river in wheteher good condition or not.
 
 Keywords: Knowledge Studies, Lambur Luar, Water Weeds

Aqueous extract from leaves of Ludwigia hyssopifolia (G. Don) Exell as potential bioherbicide.

Ludwigia hyssopifolia (G. Don) Exell, one of the problem weeds in some rice-producing countries, was studied to determine its allelopathic potential based on the effects of aqueous extracts of its tissues (leaves, roots and stem) on seedling growth of selected weeds and rice. The major phenolic compound of its leaves was also isolated and characterized. L. hyssopifolia aqueous leaf extract showed significant inhibition of shoot growth and biomass accumulation of weeds (Amaranthus spinosus L., Dactyloctenium aegyptium L., Cyperus iria L.) while maintaining less adverse effects on rice (crop) compared to other aqueous extracts of roots and stem. Phytochemical screening showed that phenols, tannins, flavonoids, terpenoids, saponins and coumarins are found in its leaf aqueous extract. The Folin-Ciocalteu method revealed that its leaves contain 26.66 ± 0.30 mg GAE g-1 leaf. The extract was then acid-hydrolyzed to liberate the phenolics (25 mg phenolics g-1 leaf). The major compound was isolated via preparative thin-layer chromatography using formic acid-ethyl acetate-n-hexane (0.05:4:6) solvent system. It had maximum UV absorption at 272 nm while its Fourier transform infrared spectrum revealed phenol, carboxylic acid and ether functionalities. This also had similar chromatographic mobility when run together with syringic acid in two-dimensional paper chromatography and thin-layer chromatography. L. hyssopifolia has potential allelopathic activity and its leaf aqueous extract showed the highest phytotoxic activity (P ≤0.05) indicating its potential as a bioherbicide. The most probable identity of the major phenolic compound is syringic acid. © 2019 Society of Chemical Industry.

Analysis of Constructed Swamp Forest Vegetation as A Phitoremediation Agent in Coal Mining, South Kalimantan

Coal mining activities could potentially interfere with the environment. One of the environmental disturbances in coal mining activities is theformation of acid mine drainage (AMD). AMD management can be done passively through the construction of swamp forest. The constructed swampforest system uses organic material in the form of cow manure which serves as a growing plants’ medium. Phytoremediation is an attempt to usevplant species in the accumulation of heavy metals. This study was aimed to know the AMD management system passively and identify the diversity ofplants in artificial swamp forests. Purposive sampling method with a sample size of 2 x 2m in 10 plots/compartments was used to identify the plantdiversity in constructed swamp forest. The observation was made both before and after AMD flowed. Constructed swamp forest consist of 6compartments (2 sediment pond compartments and 4 swamp compartments). The results of the vegetation analysis found that before the AMD flowed,21 species are still capable growing naturally in constructed swamp forest, however, it became 15 after the AMD flowed. Cyperus iria, Fimbristylisgriffithii, Scirpus juncoides, Ludwigia hyssopifolia, Cyperus platystylis and Monochoria vaginalis are six dominant species that can be used asphytoremediation agent in constructed swamp forest.Keywords: Acid Mine Drainage, constructed swamp forest, phytoremediation

Optimizing Sowing and Flooding Depth for Anaerobic Germination-Tolerant Genotypes to Enhance Crop Establishment, Early Growth, and Weed Management in Dry-Seeded Rice (Oryza sativa L.).

Poor crop establishment, high weed infestation, and consequent yield loss are major concerns for dry-seeded rice (DSR). Flooding after seeding helps in managing weeds but reduces seed germination and crop stand. Anaerobic germination (AG)-tolerant rice genotypes could overcome these problems in DSR. Screenhouse experiments were established to evaluate the effect of seed sowing depth (SD) (0.5 cm, 1 cm, and 2 cm) and flooding depth (FD) (saturated, 2 cm, and 5 cm) on crop establishment, early growth, and weed competitiveness in DSR using AG-tolerant genotypes (Khao Hlan On, Ma-Zhan Red, IR64+AG1, and IR64). Echinochloa crus-galli, Ludwigia hyssopifolia, and Cyperus difformis were used in the weedy treatment. Rice plants reached maximum emergence 9–13 days later under flooding compared with saturated conditions. Crop emergence decreased by 12–22% at 0.5 and 1 cm SD and by 48–60% at 2 cm SD, when combined with 2 or 5 cm FD compared with saturated conditions. The 2 cm SD reduced seedling emergence by 23–42% in Khao Hlan On and Ma-Zhan Red, by 62–70% in IR64+AG1, and by 90–92% in IR64 under flooding. Initial growth in rice plant height was slow under flooding but increased progressively after the seedlings emerged from water and the final height was not affected by FD. Leaf area, total shoot biomass, tiller density, and leaf number per pot of rice were higher at 1 cm SD (P< 0.05), but decreased drastically at 2 cm SD under flooding. The emergence of E. crus-galli and L. hyssopifolia decreased by 53–65% and 89–95%, respectively, but increased by 49–68% in C. difformis under 2 and 5 cm FD, respectively, compared with saturated conditions. The shoot biomass of the weeds followed the same trend. Khao Hlan On showed the highest weed-competitive ability under all FD while the biomass of IR64+AG1 and IR64 decreased by 10–14% due to weed competition under 2 cm FD. The 1 cm SD showed better growth for all genotypes under different FD. The 2 cm FD is sufficient to have a significant control of problematic weed species. The tolerance of AG of rice genotypes should be further enhanced to increase their weed-competitive ability.

Presence and Distribution of Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) in Colombia.

The presence and distribution of Scirtothrips dorsalis was reported in Colombia in the Andean, Caribbean, and Orinoquia regions, from 0 to 1,200 meters of altitude (MASL) in the warm climate zone, with less than 2,000 mm rainfall per year and a temperature above 24°C, which corresponds to the tropical dry forest life zone (TDF). Larvae and adults of S. dorsalis were found on 13 plant species belonging to 12 genera in 12 families, of 181 plant species sampled from 129 genera in 47 families sampled. The botanical species with S. dorsalis presence included cotton (Gossypium hirsutum) L., mango (Mangifera indica) L., chili pepper (Capsicum frutescens) L., bell pepper (Capsicum annuum) L., orange (Citrus sinensis) L., jasmine orange (Murraya paniculata) L., rose (Rosa sp.), and the weeds Sesbania exaltata (Mill.), Phyllanthus niruri L., Ludwigia hyssopifolia Vahl, Euphorbia hypericifolia L., Echinochloa colona L., and Amaranthus spinosus (L.). S. dorsalis prefers young leaves and floral structures, but in cotton it was also associated with squares. The low number of host plants is evident, far from the extensive lists obtained by other authors in other latitudes. S. dorsalis invaded Colombia only in recent years, and this is the first study of the presence and distribution of this thrips in the area.

CLASSIFICATION OF PADDY WEED LEAF USING NEURO-FUZZY METHODS

Paddy weed appears to be one of the many visible threats to paddy crop production and subsequently farmers’ income. It is for this reason that the growth of paddy weeds in paddy fields should be controlled as it results in a significant decrease of paddy yields. However, farmers might have limited knowledge on weed types, and are thus unable to identify and determine the right prevention methods. This paper presents classification methods for paddy weeds through the leaf shape extraction and applies neuro-fuzzy methods for recognizing the types of weeds. The types being focussed are the Sphenoclea zeylanica, Ludwigia hyssopifolia and Echinochloa crus-galli. The developed e-prototype methods would be able to classify paddy weeds with 83.78% accuracy. Hopefully, the findings in this study would assist farmers and researchers in increasing their paddy yields and eliminating weed growth respectively. The production of paddy in Malaysia would eventually be improved with the proposed methods, which can be considered as a technology advancement in the field of paddy production.