Central Row Research Articles

Ultra-wideband slow light transmission with high normalized delay bandwidth product in W3 photonic crystal waveguide

By separating two photonic crystals with a distance of 23a, where a is the lattice constant, shifting the positions of some discriminatory air holes in the upper and lower edges, and inserting a defect central row, a specific waveguide is set up, W3 photonic crystal waveguide (W3 PCW). An equivalent transmission line model is given, giving the theoretical basis of for the proposed waveguide to have a wider transmission bandwidth and thus higher normalized delay bandwidth product (NDBP). Slow-light properties and performance are studied by using plane-wave expansion and finite-difference time-domain methods. We obtained ultra-wideband of 65.70 nm with low group-velocity dispersion and at the same time a high NDBP of 0.496 through optimization which is a worthy indicator for slow light device performance. Wider bandwidth can allow shorter duration of pulse waves, causing higher field intensity and stronger nonlinear effect.

Abundance of natural enemies of Nezara viridula (Hemiptera: Pentatomidae) on three cultivars of sweet alyssum

AbstractThe southern green stink bug, Nezara viridula is one of the most serious pests of tomatoes in Florida. During 2014 and 2015 tomato cropping seasons, three cultivars of sweet alyssum, Lobularia maritima (Brassicales: Brassicaceae) were evaluated in north Florida to determine their effectiveness in conserving the natural enemies of the southern green stink bug in open field conditions. The experimental refuge crops were cultivated on two outer rows and one center row of the tomato crop. Each section of the rows of trap crops and refuge crops was 20 × 3 ft. (6 × 0.91 m) in size. Pest insects and their natural enemies were collected weekly and identified. On refuge crops, big‐eyed bug, Geocoris punctipes (Hemiptera: Geocoridae); minute pirate bug, Orius insidiosus (Hemiptera: Anthocoridae), ladybird beetles (Coleoptera: Coccinelidae), assassin bugs (Hemiptera: Reduviidae), damsel bugs (Hemiptera: Nabidae), hover flies (Diptera: Syrphidae) and spiders (Arachnida) were collected. All cultivars of L. maritima attracted the natural enemies of the southern green stink bug; however ‘carpet of snow’ was the most effective cultivar followed by ‘tall white’ in attracting G. punctipes in the tomato crop. N. viridula population first peaked in July and declined in week 11 and then had a sharp increase in weeks 12 and 13 when G. punctipes population was comparatively high. Data on the availability of suitable refuge crops which provide nectar and shelter to natural enemies are useful for integrated pest management of the southern green stinkbug, because these plants provide necessary resources to conserve beneficial species.

Soil Load-Bearing Capacity and Development of Root System in Area Under Sugarcane with Traffic Control in Brazil

Attempts to achieve reduced traffic area and favorable conditions for sugarcane field durability have been made increasingly necessary to use traffic control techniques in areas of sugarcane production. Our goal was to assess the benefits of traffic control for sugarcane cultivation areas by using a load-bearing capacity modeling and developing a root system. Our experiment was conducted in a sugarcane cultivation area in the region of Nova Europa, Sao Paulo, Brazil, by assessing the following treatments: T1 = sugarcane planted with row spacing of 1.50 m managed without autopilot; T2 = sugarcane planted with row spacing of 1.50 m managed with autopilot; T3 = sugarcane planted with row spacing of 1.5 × 0.90 m managed with autopilot. Soil sampling occurred at layers of 0.00–0.15 and 0.15–0.30 m in inter-row center and seedbed region. Our results reveal that the use of autopilot in the seedbed area is less influenced by machinery traffic, which guarantees preserved soil structure maintenance in the plant row region. Mathematical models of the inter-row center presented higher load-bearing capacity values than the seedbed region for all treatments, layers, and cycles assessed. Additionally, load-bearing capacity increases as the sugarcane cultivation cycles evolve, including higher soil load-bearing capacity at the first ratoon cane cycle in relation to the cane-plant cycle. Finally, the sugarcane crop root system has good distribution during the cane-plant cycle; however, the first ratoon cane cycle has a downward trend for the plant rows in the inter-row center because of intensive machine traffic.

Análisis taxonómico de las especies mexicanas de Belonuchus Nordmann del grupo ephippiatus (Coleoptera: Staphylinidae)

We analyzed 117 specimens from eight Mexican states and 22 localities whose taxonomic identification was doubtful to assign them to Belonuchus ephippiatus or B. erytrhopterus. The goal of this paper is to analyze the most important characters reported in the literature to separate both species and decide if it is one or two entities. The analysis included the measurement of different parts of the body and the proportions between them, but this one focused on the total body length, the number of punctures that form each of the two central rows of the pronotum, the aedeagus length and its proportion in relation to the body length, since they are the most important characters indicated in the literature that allows to separate the two species. The results show that it is not possible to distinguish two species with any of the characters analyzed, combined or alone, so it was proposed for the second time in the history of these species that B. erythropterus is a junior synonym of B. ephippiatus. Aspects of the great morphological variation observed in B. ephippiatus, its geographic distribution and its biology are discussed. Finally, a new species of the same species group is described and it is distinguished from B. ephippiatus, besides providing schemes and photographs that help its recognition.

Machine vision for orchard navigation

Developing a machine vision based autonomous utility vehicle for agricultural application is a challenging task due to changing physical landmarks. While most research thus far has developed algorithms that take advantage of ground structures such as trunks and canopies in the orchard, this research uses the combination of the canopy with the background sky. By focusing on the tree canopy and sky of an orchard row, an unmanned ground vehicle can extract features that can be used for autonomously navigating through the center of the tree rows. This was attempted by using a small-unmanned ground vehicle platform driven by four motors and guided by a machine vision system. The machine vision system is composed of a multispectral camera to capture real-time images and a personal computer to process the images and obtain the features used for autonomous navigation. Laboratory field tests showed that the small vehicle platform system was able to navigate autonomously with an RMS error of 2.35 cm. Field tests using a peach orchard showed that the small vehicle platform system could navigate the rows autonomously with an RMS error of 2.13 cm. The machine vision algorithm developed in this study has the potential to guide small utility vehicles in the orchard in the future.

Populational fluctuation of lace bug in cassava

ABSTRACT: Vatiga illudens is a pest of economic importance for the cultivation of cassava. Knowing the time of incidence of this insect in combination with environmental factors enables control strategies. The objective of this study was to determine the population dynamics of V. illudens in cassava cultivars and the correlation of these insects for climatic factors in Dourados, Mato Grosso do Sul. Four cultivars of cassava were evaluated: Kiriris, N-25, IAC 90 and Fécula Branca. Population assessment of the lace bug was conducted over 18 months observing 2 crop cycles. Fortnightly, they were randomly sampled four central plants of each plot and five leaves from the middle third of each plant, quantifying the number of nymphs and adults per leaf. Twenty months after planting cassava, two central rows of each plot were harvested and measured productivity in kg ha-1. The experimental design was randomized blocks with four treatments and two replications. The peak population of nymphs and adults for the first crop cycle occurred during the months from March to May. For the second cycle, these population indices happened in the months from January to April. Cultivar Kiriris showed the highest mean number of nymphs and adults per leaf cassava and cultivar IAC 90, the lowest number of insects. There was a negative correlation between the population of adult insects and root yield. The maximum, mean and minimum temperatures affected the population of nymphs V. illudens. These results are fundamental to define management strategies for control of lace bug.

Intraspecific competition in oat varieties selected for grain yield and milling

Oats likely emerged as part of the weedy grass assemblage in early wheat and barley crops. Some Avena species, such as A. fatua and A. sterilis, evolved into aggressive weeds, and the high interspecific competitive ability of cultivated oats (A. sativa) is valued agronomically to facilitate weed control in rotations. We tested the hypothesis, verified in many crops, that high yield of oats is related to low intraspecific competitive ability. Ten contemporary oat varieties, selected for grain yield and milling attributes, where grown in three environments. Response to competition was calculated as 100 × (Yb – Yc)/Yc, where Y is yield measured in border (b) and centre (c) rows. The same definition was used to calculate response to competition of yield components (biomass, harvest index, grain number, grain weight) and the components of grain number (panicle number and grains per panicle). Yield response to competition was affected by all three sources of variation, i.e. environment, variety and variety × environment interaction. The interaction demonstrates the plasticity of yield response to intraspecific competition; for example, the response to competition of variety Mortlock varied from 9% to 71% among environments. This plasticity in yield response to competition was partially related to variety-dependent responses to competition for biomass and harvest index, number of panicles and number of grains per panicle. We did not find the expected negative association between yield and variety-dependent response to competition. We discuss how this lack of correlation could relate to sampling issues, i.e. a limitation in the range of environments and varieties explored in this study, or reflect a legitimate feature of oat crops arising from early and contemporary selective pressures.

Finite element simulations on the ultimate response of extended stiffened end-plate joints

The design criteria and the corresponding performance levels characterize the response of extended stiffened end-plate beam-to-column joints. In order to guarantee a ductile behavior, hierarchy criteria should be adopted to enforce the plastic deformations in the ductile components of the joint. However, the effectiveness of thesecriteria can be impaired if the actual resistance of the end-plate material largely differs from the design value due to the potential activation of brittle failure modes of the bolt rows (e.g., occurrence of failure mode 3 in the place of mode 1 per bolt row). Also the number and the position of bolt rows directly affect the joint response. The presence of a bolt row in the center of the connection does not improve the strength of the joint under both gravity, wind and seismic loading, but it can modify the damage pattern of ductile connections, reducing the gap opening between the end-plate and the column face. On the other hand, the presence of a central bolt row can influence the capacity of the joint to resist the catenary actions developing under a column loss scenario, thus improving the joint robustness. Aiming at investigating the influence of these features on both the cyclic behavior and the response under column loss, a wide range of finite element analyses (FEAs) were performed and the main results are described and discussed in this paper.

Potential use of <em>Mucuna bracteate</em> as a Cover Crop for Coconut Plantations in the Low Country Intermediate Zone of Sri Lanka

Cover crops provide a wide range of ecological and environmental benefits. Mucuna bracteata is one of the leguminous creepers which has superior characteristics such as fast growth, high nitrogen fixation ability, high biomass production, and free from pest and diseases. While this plant has recently been used as a cover crop in rubber plantations in the Wet Zone of Sri Lanka, it has not been tested under coconut cultivation in the Intermediate Zone. Therefore, this study aimed to assess the suitability of Mucuna bracteata as a cover crop in coconut plantation in the Low Country Intermediate Zone of Sri Lanka. Four treatments tested in the experiment were, T1 - Mucuna bracteata planted in two rows, T2 - Mucuna bracteata planted in three rows, T3 - Mucuna bracteata planted in four rows in center of square under coconut cultivation and T4 - Coconut without cover crop (control). The treatments were arranged in a randomized complete block design with four replicates. Soil chemical and physical properties were analyzed at 5 cm - 25 cm depth. The ground cover, weed density and total biomass production were also evaluated in different planting systems. The highest ground coverage and the lowest weed density were observed in coconut with Mucuna bracteata in three rows at 75 days after field establishment. Mucuna bracteata planted plots had significantly lower bulk density, higher organic carbon content than the control and there was no significant bracteata planted in three rows is the most suitable planting method being able to give better ground cover, lower soil bulk density and higher soil nitrogen than other treatments. According to the results of the study, it can be concluded that Mucuna bracteata could be well grown as a cover crop under coconut in the Intermediate Zone of Sri Lanka. Also, it can be suggested that Coconut with Mucuna bracteata planted in three rows is the most suitable planting method being able to give better ground cover, lower soil bulk density and higher soil nitrogen than other treatments.

Energy distribution and melting efficiency in glass melting channel: Diagram of melt flow types and effect of melt input temperature

The synergy between glass melting and glass flow character was investigated by mathematical modelling of a Joule heated glass melting channel with a central longitudinal row of vertical heating electrodes. The glass melt containing sand particles and bubbles entered the channel where different types of the melt flow were set up. The sand particle dissolution and the bubble removal were monitored up to the achievement of phenomena completion. The increasing fraction of energy supplied to the input region of the channel proved to be crucial for setting up the beneficial character of the melt flow and consequent increase of the melting performance. When the temperature of the inputting melt decreased, the melting performance also decreased. The relations of the “energetic model” were derived and applied to predict the beneficial type and conditions of the melt flow. The best results have been obtained for the flow character near the uniform flow. The beneficial state was achieved when each region of the channel was supplied by the energy needed there for glass heating and heat losses. The impact of the temperature of the inputting melt on the detailed character of the melt flow was discussed with the help of the energetic model.

Effect of the injection angle on local heat transfer in a showerhead cooling with array impingement jets

An experimental study was conducted to investigate the effect of the injection angle for staggered array impingement jets in a showerhead cooling system. We suggested the angled jets array to enhance heat transfer performance, and heat transfer characteristics were compared to that on the normal jets array. The semicircle test section was designed to consider the showerhead configuration, and the Reynolds number was changed from 3000 to 10,000. The naphthalene sublimation method was used to evaluate the heat transfer coefficients on targeted plates, and the numerical simulations were carried out to analyze the characteristics of the flow fields. The averaged heat transfer coefficient increased monotonically with increasing Red due to the enhanced flow mixing by increasing mass flow rate. A low heat transfer coefficient was observed among the adjacent impingement jets in the vicinity of the central row of holes due to staggered array pattern and curvature effect. To overcome this disadvantage, the inclined jets were applied in present study. The heat/mass transfer coefficients were larger for the inclined jets for all Red because an amount of wall jet is flowed toward the low heat transfer region by flow imbalance. As applied inclined array impingement jets, averaged heat transfer was enhanced about 9% in low Red compared to normal array impingement jets.

Dictyosporium wuyiense sp. nov. from Wuyi Mountain China

Dictyosporium wuyiense, a new anamorphic fungus collected on a dead branch of bamboo in Tongmugou, Wuyi Mountain, China, is described and illustrated. It is characterised by being cheiroid, septate, complanate, and yellow, with two types of conidia composed mostly of five parallel compact rows of cells, sometimes with variable hyaline apical vesical appendages. Type 1 conidia are longer and the three central rows are protruding with swollen apical cells; type 2 conidia are wider and fan-shaped, with rows of apical cells approximately the same length. The conidial morphology on potato dextrose agar plates was variable, most with 2–3 vesical appendages. In phylogenetic analyses of the internal transcribed spacer (ITS) of rDNA, Dictyosporium wuyiense clustered with most Dictyosporium species in Dictyosporiaceae, but was a distinct species. Both morphological and molecular evidence support its description as a new species. A brief review of Dictyosporium and allied species is provided.

Flat-Band Slow Light in a Photonic Crystal Slab Waveguide by Vertical Geometry Adjustment and Selective Infiltration of Optofluidics

In this paper, a photonic crystal slab waveguide (PhCSW) for slow light applications is presented. To obtain widest possible flat-bands of slow light regions—regions with large group index (n g), and very low group velocity dispersion (GVD)—two core parameters of PhCSW structure are investigated. The design procedure is based on vertical shifting of the first row of the air holes adjacent to the waveguide center and concurrent selective optofluidic infiltration of the second row. The criteria of $${{\langle n_g \rangle}}$$ ± 10% variations is used for ease of definition and comparison of flat-band regions. By applying various geometry optimizations for the first row, our results suggest that a waveguide core of W 1.09 would provide a reasonable wide flat-band. Furthermore, infiltration of optofluidics in the second row alongside with geometry adjustments of the first row result in flexible control of 10 < n g < 32 and provide flat-band regions with large bandwidth (10 nm < Δλ < 21.5 nm). Also, negligible GVD as low as β 2 = 10−24 (s2/m) is achieved. Numerical simulations are calculated by means of the three-dimensional plane wave expansion method.

Evaluation of the efficiency of maize ecotypes in different localities and times in the Ancash region, Peru

The objective of the present investigation is to evaluate the yield of the maize crop against the current climatic variability. In this sense, plots were installed in each locality at the beginning of each agricultural season (October, November and December), with two densities, one at commercial density 80 x 60 cm and three plants per plot and at a low density of sowing per hybrid 3 Plants / m2, with an experimental area per plot (furrows, 4 for each density) in order to have the necessary material for the sampling to be carried out during the crop cycle; Evaluations, observations and measurements were made on the two central rows. The plots were irrigated and fertilized so that there was no water or nutritional deficiency.The ecotypes studied were Huaraz, Yungay, Chingas and Marcará, with the result that the ecotypes with the highest yield (kgrs) were, in the town of Canyasbamba, the ecotypes Huaraz, Chingas and Marcará, in the locality of Huaraz the ecotype Chingas and in the locality of Tingua the best behavior was generated by the ecotype Marcará.

Water use efficiency and evapotranspiration in maize-soybean relay strip intercrop systems as affected by planting geometries.

Optimum planting geometries have been shown to increase crop yields in maize-soybean intercrop systems. However, little is known about whether changes in planting geometry improve the seasonal water use of maize and soybean intercrops. We conducted two different field experiments in 2013 and 2014 to investigate the effects of changes in planting geometry on water use efficiency (WUE) and evapotranspiration (ETc) of maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] relay strip intercrop systems. Our results showed that the leaf area index of maize for both years where intercropping occurred was notably greater compared to sole maize, thus the soil water content (SWC), soil evaporation (E), and throughfall followed a decreasing trend in the following order: central row of maize strip (CRM) < adjacent row between maize and soybean strip (AR) < central row of soybean strip (CRS). When intercropped, the highest grain yield for maize and total yields were recorded for the 40:120 cm and 40:160 cm planting geometries using 160 cm and 200 cm bandwidth, respectively. By contrast, the highest grain yield of intercropped soybean was appeared for the 20:140 cm and 20:180 cm planting geometries. The largest land equivalent ratios were 1.62 for the 40:120 cm planting geometry and 1.79 for the 40:160 cm planting geometry, indicating that both intercropping strategies were advantageous. Changes in planting geometries did not show any significant effect on the ETc of the maize and soybean intercrops. WUEs in the different planting geometries of intercrop systems were lower compared to sole cropping. However, the highest group WUEs of 23.06 and 26.21 kg ha-1 mm-1 for the 40:120 cm and 40:160 cm planting geometries, respectively, were 39% and 23% higher than those for sole cropping. Moreover, the highest water equivalent ratio values of 1.66 and 1.76 also appeared for the 40:120 cm and 40:160 cm planting geometries. We therefore suggest that an optimum planting geometry of 40:160 cm and bandwidth of 200 cm could be a viable planting pattern management method for attaining high group WUE in maize-soybean intercrop systems.

Hadoop on Named Data Networking

In today's data centers, clusters of servers are arranged to perform various tasks in a massively distributed manner: handling web requests, processing scientific data, and running simulations of real-world problems. These clusters are very complex, and require a significant amount of planning and administration to ensure that they perform to their maximum potential. Planning and configuration can be a long and complicated process; once completed it is hard to completely re-architect an existing cluster. In addition to planning the physical hardware, the software must also be properly configured to run on a cluster. Information such as which server is in which rack and the total network bandwidth between rows of racks constrain the placement of jobs scheduled to run on a cluster. Some software may be able to use hints provided by a user about where to schedule jobs, while others may simply place them randomly and hope for the best. Every cluster has at least one bottleneck that constrains the overall performance to less than the optimal that may be achieved on paper. One common bottleneck is the speed of the network: communication between servers in a rack may be unable to saturate their network connections, but traffic flowing between racks or rows in a data center can easily overwhelm the interconnect switches. Various network topologies have been proposed to help mitigate this problem by providing multiple paths between points in the network, but they all suffer from the same fundamental problem: it is cost-prohibitive to build a network that can provide concurrent full network bandwidth between all servers. Researchers have been working on developing new network protocols that can make more efficient use of existing network hardware through a blurring of the line between network layer and applications. One of the most well-known examples of this is Named Data Networking (NDN), a data-centric network architecture that has been in development for several years. While NDN has received significant attention for wide-area Internet, a detailed understanding of NDN benefits and challenges in the data center environment has been lacking. The Named Data Networking architecture retrieves content by names rather than connecting to specific hosts. It provides benefits such as highly efficient and resilient content distribution, which fit well to data-intensive distributed computing. This paper presents and discusses our experience in modifying Apache Hadoop, a popular MapReduce framework, to operate on an NDN network. Through this first-of-its-kind implementation process, we demonstrate the feasibility of running an existing, large, and complex piece of distributed software commonly seen in data centers over NDN. We show advantages such as simplified network code and reduced network traffic, which are beneficial in a data center environment. There are also challenges faced by NDN that are being addressed by the community, which can be magnified under data center traffic. Through detailed evaluation, we show a reduction of 16% for overall data transmission between Hadoop nodes while writing data with default replication settings. Preliminary results also show promise for in-network caching of repeated reads in distributed applications. We show that while overall performance is currently slower under NDN, there are challenges and opportunities for further NDN improvements.

Description and phylogenetic investigation of Pogonatum shevockii N.E.Bell & Hyvönen (Polytrichaceae), a new East Asian species with a unique leaf morphology

We describe Pogonatum shevockii from Taiwan, a new species with a number of unusual features. A single collection from Yunnan is treated as conspecific, although further sampling is required to confirm whether morphological and molecular differences from the Taiwanese material are sufficiently consistent to be recognised taxonomically. The plants have a remarkable leaf structure with a 3-stratose lamina including a central row of large hyaline cells that may be responsible for the abaxial surfaces of leaves appearing distinctly pale-glaucous when dry. These cells often have globular inclusions that appear variously dark or speckled yellow-brown/blue-green depending on magnification. In fresh material of Taiwanese specimens the calyptra hairs are often distinctly green, another unusual feature in the Polytrichaceae. Molecular phylogenetic analyses including exemplars from 75% of Pogonatum species strongly support the monophyly of the new taxon and tentatively place it as sister to a clade including five species with geminate apical lamellar cells, namely the exclusively Central and Southern American P. campylocarpum, P. neglectum, P. comosum and P. procerum and the Asian P. microstomum.

The History and Distribution of ṭāb: A Survey of Petra’s Gaming Boards

The History and Distribution of <i>ṭāb</i>: A Survey of Petra’s Gaming Boards

Determining Grapevine Canopy Effects on Effective Rainfall in Vineyards

Rainfall interception was determined for six trellis systems in a vineyard at Stellenbosch. Measurements made directly under the canopy and in the centre of the work row were compared to rainfall measured outside the vineyard. Rainfall was measured over two growing seasons from October until March. There was no difference between rainfall in the centre of the work rows and rainfall outside the vineyard. Due to the effect of seasonal increases in leaf area on rainfall that penetrated through the canopy, rainfall interception was estimated from rainfall measured outside the vineyard, as well as day of season when it occurred by means of multiple linear regressions. Since canopy orientation also influenced the amount of water that reached the soil surface, two regression equations were developed that explained 96% and 89% of the variation in the amount of water that reached the soil surface under slanting and vertical canopies, respectively. On average 86 % and 80 % of the rainfall landed under slanting and vertical canopies, respectively. Based on the assumption that rainfall on the uncovered fraction of the work row was similar to the rainfall measured outside the vineyard, the calculated weighted mean rainfall over the total area did not differ drastically from actual rainfall. This indicated that canopy effects on rainfall interception in vineyards were relatively small.

English

Turcicum leaf blight (TLB) (Exserohilum turcicum) is a major disease affecting maize production in western Ethiopia. The objectives of this study were to determine the effect of maize varieties integrated with fungicides on epidemics of turcicum leaf blight; to determine the effect of turcicum leaf blight severity on yield and yield components of maize; and to assess the cost and benefit of using fungicides. The field experiment was conducted at Bako Agricultural Research Center in 2014 main cropping season using six maize varieties (BH-540, BH-543, BH-546, BH-660, BH-661 and AMHQ-760) integrated with foliar sprays of the systemic fungicide propiconazole (Tilt) at the rate of 350 ml ha-1and the contact fungicide mancozeb (Dithane M-45) at 2.6 kg ha-1. The experiment was arranged in 3 × 6 factorial combinations in split plot design with three replications. A pinch of ground maize leaf infected by E. turcicum was inoculated at third-fifth leaves. Unsprayed plots were left as control or check for each variety. Disease severity was scored using 1 to 5 scale on 12 randomly-tagged plants in the central rows. Integration effects of varieties with fungicides significantly affected the grain yield and thousand kernel weight (TKW) of maize varieties. The highest (11383 kg ha-1) grain yield was obtained from propiconazole-treated hybrid maize variety BH-546. Turcicum leaf blight resulted in grain yield losses of up to 40.7% on the unsprayed plots of the susceptible variety BH-543. Percent severity index, AUDPC, incidence and disease progress rates were negatively correlated with yield components regardless of grain yield loss. The highest marginal benefit (ETB 48,801.28 ha-1) and marginal rate of return (ETB 6.33) were obtained from propiconazole-treated varieties BH-543 and BH-546, respectively. This study contributes to integrated TLB management options, and to make a valid recommendation for TLB management strategy, the study should be repeated over years and locations where TLB of maize is of major economic importance. Key words: Exserohilum turcicum, fungicides, percent severity indices, maize-varieties, yield.