Sporangial production and infection require a film of moisture for 12-96 hours. The disease appears on plants at pre- flowering stage (40 to 50-day old plant) and within a period of 15 to 20 days spreads under favourable conditions from the lower most sheath to the ear shoot. Presently, the disease is considered as a major disease not only in India but also in several countries of Tropical Asia wherever maize is grown. In recent years, the incidence of P. polysora has taken a heavy toll in majority cultivars grown in Karnataka namely Mysore, Mandya, Hassan, Kolar, part of Coorg, Shimoga and Chitradurga district. Brown Spot Disease: This disease mainly occurs in sub-tropical and intermediate areas. In this, the problem in diseased plants have much less kernels than on healthy plants. Stalk rot, ear rot, kernel rot can occur in infected tissue although many times infected tissue have no symptoms. As the leaves are infected by the pathogen, it drastically reduces the total photosynthetic area of the diseased plants, causing reduction in grain yield. The disease kills the plant prematurely after flowering. In some cases the infection (light to dark brown rotting) may spread rapidly throughout the leaf sheath and cause withering of leaf sheath and leaf under favourable environmental conditions. Sow the seed before rainy season begins. The presence of mycotoxin traditionally regarded as indication of poor storage condition, but they may present in grains before coming to storage. These are maize mosaic virus I, maize mosaic (a strain of sugarcane mosaic virus) and vein enotion. Sow the resistant varieties like GS-2 and Ganga-101 which are comparatively resistant. Round to elongated uredo-pustules are on both the surfaces of the leaf. Singh and Sharma (1976) estimated 40.5 per cent loss in grain yield with 71 per cent disease index. In young seedlings the plants dry up in the early stage of the growth. Spraying of fungicides such as mancozeb at the rate 2.5-3.0 per cent as soon as disease symptoms appear to protect valuable and breeding materials. The lack of information is more acute in the developing countries, where there is a lack of trained personnel and appropriate equipment, and mostly to the concept that when these viral diseases are present, nothing can be done to control them. Viral and fungal diseases are recorded as causing mortality of armyworms. Infected maize leaves become chlorotic and dry. The general symptoms of the disease are poor emergence or patchy growth of seedlings or the seedlings become pale yellow or dry up just after germination. Black Bundle Disease (Cephalosporium acremonium Corda): Banded Leaf and Sheath Blight (BLSB) Disease, The best answers are voted up and rise to the top. The individual flowers may be infected on tassel and even through individual flower parts may be transformed into galls. Plant disease epidemiologists strive for an understanding of the cause and effects of disease and develop strategies to intervene in situations where crop losses may occur. ]: 9. Diseases in maize require certain environmental conditions to develop. 2 and SSR markers closely linked to this locus. This rot caused by Aspergillus spp. Biology, Plant Pathology, India, Cereals, Maize, Diseases, Diseases in Maize. iv. This has been found to be prevalent in the several states and the incidence ranges from 2.2 to 10.6 per cent. There are no chemical controls available. i. The impact of foliar diseases on forage maize contamination is regarded to be low, as Fusarium infections are restricted to some parts on the leaf sheaths and husks. They could be shaken off or killed chemically. The disease is common during rainy season under hot and high soil moisture conditions. There are two fungal pathogens that cause GLS: Cercospora zeae-maydis and Cercospora zeina. Diseases caused by viruses (such as Maize Streak transmitted by leafhoppers of the genus Cicadulina in countries of tropical subequatorial Africa, Rayado Fino transmitted by the leafhopper Dalbulus maidis in Latin America and southern USA, Maize Dwarf Mosaic Virus transmitted either through infectious sap or the aphid Rhopalosiphum maidis) are creating concern in maize … While the genetic basis of resistance to multiple fungal pathogens has been studied in maize, less is known about the relationship between fungal and bacterial resistance. at the rate 0.25 per cent is a good safeguard against any possible seed-borne infection. ii. Pre-Flowering Stalk Rot Disease 7. The telia are circular to elongate, 0.2-0.5 mm in diameter dark chocolate brown to black and remain covered by the epidermis longer then the common rust. The disease caused drastic reduction in grain yield-to the tune of 97 per cent and exhibited a direct correlation with other yield parameters. The tooth pick method as described for post flowering stalk rot development can be used to inoculate plants at knee high stage (30-35 days) for screening genotypes, Payak (1971), Payak and Sharma (1985). Harvest is slowed if stalk rot is severe and losses also occur due to time loss during harvest. Affected plants produce malformed tassels or aborted ears which may appear at any time of silking, but the plants affected early are stunted and often die. Maize grown in cooler areas usually contains low amount of mycotoxin. 15. 10S accounted for 83% of phenotypic variation for polysora rust resistance in a mapping population based on cross between tropical x temperate lines, with the tropical inbreds as a sources of resistance to polysora rust. Only young plants are susceptible. The damage is most common at or near the tip of the ear; silk infection is favoured by high night and day temperature. Oospores remain viable for at least three years and this viable oospores material constitutes the main source of inoculums. zeae) belong to pre-flowering type, while others such as late wilt, charcoal rot, Fusarium wilt and stalk rot, Acremonium stalk rot, Botryodiplodia stalk rot belong to the post-flowering type. The disease causes direct losses, resulting in premature death, stalk breakage and ear rot indirect losses by reducing the grain yield. The plants may topple down at this stage. Fitzp. Stripes may also be formed on sheaths, husks, and the stalks. It is … Basic requirements Corn is best grown in warm, tropical and sub-tropical regions as it requires warm soils to develop optimally. These types of studies are confounded by year-to-year in average yield. Thus in the former case only one change in the fungus is required to develop tolerance.Treatment of seed with apron 35 w.p. There seems to be no controversy about soil borne of the disease. Pests, weeds and disease in maize crops can severely reduce yield and quality. Its seed borne nature is controversial. A study conducted at Rajasthan, indicates that the yield loss in hybrid Ganga 5 was 27.0, while in the local open-pollinated variety it was Malan 24.5 per cent. The highest disease intensity i.e. These fungi are responsible for microbial spoilage of the grins and production of mycotoxins in pre- and post harvest stages. Three sprays of Dithane M-45 beginning from first appearance of symptoms at 15 days interval can minimize the disease. etc., under conditions favourable for disease development, susceptible materials suffer heavy blightening resulting in premature drying of leaves and lightweight kernels. Much like diseases of humans and other animals, plant diseases occur due to pathogens such as bacteria, viruses, fungi, oomycetes, nematodes, phytoplasmas, protozoa, and parasitic plants. मक्का के 5 प्रमुख रोग और उनका प्रबंधन 1. Planting the crop on ridges rather than in flat soil is recommended. i. The primary source of inoculums are sclerotia in the soil and grass hosts that grow in the vicinity of maize crop. The sources of resistance are; NAI 112, SKV 18, SKV 21, NAH 2049 (Nithyashree) a resistant hybrid to Polysora rust, TLB and SDM has been released in Karnatka. This explain why high disease incidence occurs when the field is water logged, low lying or poorly drained, plant age (pre-flowering stage) and high plant population (< 60,000 /ha). The disease generally appears at pre-flowering stage in 40-50 day old plants. Fusarium ear rot caused by F. moniliforme symptom of this disease is pink to reddish brown discoloration on the kernels and later on it spread on whole ear. What are the different sources of air pollution? This disease usually affects maize grown in the tropics to moderate. SEEDING . Our mission is to provide an online platform to help students to share notes in Biology. Rain drizzle or even heavy dews allow disease formation. Acidovorax avenae (Manns) Willems et … Another study reported in a different genetic background, a QRL (Quantitative resistant locus) to P. polysora on chr. A characteristic sign of disease is the presence of numerous, minute, black sclerotia, particularly on the vascular bundles and inside the rind of the stalk. Infected plants do not... 3. Corn planted and harvested late and grown under nitrogen stress more commonly contains aflatoxins prior to harvest than corn grown under good management practices and supplied with adequate nitrogen. Fusarium Stalk Rot [Fusarium moniliforme Sheld. Polysora rust is a warm weather disease favoured by wet weather infection and disease development at temperatures (27°C) and high relative humidity. In India, in early sixties the disease was little more than a curiosity and a disease of minor importance in the western and central Himalayan foothill region. What are the general characters of bryophytes? Teliospores of P. polysora are rare and are not known to be germinated therefore they are unimportant in disease cycle. Yield loss may result from premature plant death, thus stopping normal grain fill. i. When outer stalk tissue is brown, pith tissue in the lowest internodes is rotted and pulled away from the rind, which may result in lodging. The maize association panel used in this study is a collection of inbred lines from public breeding programs worldwide and represents substantial diversity present in maize (11, 19).In our experiments, the panel exhibited extensive variation in quantitative resistance to each of the diseases. The severity of the disease is influenced by temperature and moisture. Maize varieties. The hyphal masses on ears produce a caking effect and cement the husk leaves as well as styles (silk fibers) together. Wineland]: The disease appears both on young and adult plants of maize. Ears frequently abort and are replaced by leafy buds. The resulting diseases cause important losses in production both in crop and after harvest. Most of these diseases are prevalent on maize in the humid coastal and rainforest areas if the tropics and are less troublesome in the drier areas of the interior. ), MAIN PESTS AND DISEASES OF FRENCH BEANS (Phaseolus vulgaris), MAIN PESTS AND DISEASES OF PINEAPPLE (Ananas comosus), MAIN PESTS AND DISEASES OF MAIZE (Zea mays), SUSTAINABLE PEST MANAGEMENT IN GREEN HOUSES AND HIGH TUNNELS, How to make Your Own Animal Feeds (For Cattles and Sheep), DISEASES OF OKRA (Abelmoschus esculentus), Graphical Representation of Market Prices for September 2020, Graphical Representation of Market Prices for March 2020. Of these, seven are caused by Peronoslerospora species, two by Sclerospora and one by Euclerospora. Three viruses occurs on maize in India. www.kws-uk.com. The gall may appear on the stem, leaves, axillary’s buds and parts of the male flower. It is therefore crucial that a maize producer be able to identify the disease, says Dr Belinda Janse van Rensburg, plant pathologist at the Agricultural Research Council’s Grain Crops Institute. In India, the disease was first recorded from Tarai region of Uttar Pradesh in 1960. Infection follows some form of injury, bird damage, feeding of corn borers. This results in reduced grain quality and potential dockage when the grain is marketed. South India especially in TN and Karnataka have been reported epidemic at various times. In some cases the red streak may also be observed. Secondary spread of disease is by contact of infected leaves with parts of adjoining healthy plants. However, they do not appear to present a problem. Another component of yield loss is that plants with stalk rot may lodge and not be harvested with mechanical equipment. The optimum temperature for in vitro growth of the pathogens is 30°C and the highest level of disease is induced when RH is in the range of 90-100 per cent. Based on the work carried out the management strategies for the Polysora rust is given below: i. 5. This disease mainly occurs in sub-tropical and intermediate areas. Seeds with less than 15 per cent moisture content produce healthy plants. Because losses due to stalk rot may occur in several ways, yield loss estimates are difficult to obtain. Avoid water stress after flowering of the plant. sasakii Exner, has become increasingly severe and economically important disease of maize during last two decades or so. It is distributed in the entire Himalayan area as also in states of Rajasthan and Karnataka. The tassel is partly or wholly converted into smut spores. Diseases of maize 1. Plants are weak and those with rotted stalks always have rotted roots. Of the many foliar blight diseases occurring in India, three may be considered important based on geographical distribution and yield loss potential. Clinton]: This attacks maize, sorghum and other grasses and is moderately destructive disease in the sub-temperate, intermediate zone of hilly areas of Rajouri and Poonch districts of J&K. PEST AND DISEASES OF MAIZE Pests of Maize (1) Stem borers: The larvae bore holes into young stems and destroy the tissue, leading to low yield or death of the plant. Why does plant cell possess large sized vacuole? Secondary spread by basidiospores has not been observed in maize crop. The symptoms manifest on leaves, sheaths, stalk and ear. Bacterial diseases. iii. Content Guidelines 2. Changes in Diseases Spectrum Scenario of Maize: There is a major shift in disease pattern during the past years as the major diseases like TLB, MLB, BSDM and ESR are gradually becoming diseases of lesser economic importance now a days due to availability and use of sources of resistance in the newly developed hybrids and varieties. Virus Diseases 3. Key to maize ratings (1) End use Huge collection, amazing choice, 100+ million high quality, affordable RF and RM images. Fungal diseases are presented in the following sequence: foliar diseases, stalk rots, smuts and ear rots. Information supplied by COLEACP to be found at https://pip.coleacp.org. Image courtesy of agrifarming.in, PEST AND DISEASES OF YAM (Dioscorea spp. 7. There are a multitude of maize varieties available. at the time of silking. Cob Rots Disease 12. Air born spores present on residues can land on corn silks when it turns dark brown. Now it has become increasingly severe and assumed epidemic proportions in the next two decades. With the growing age of plant, leaves in the whorl become chlorotic and in turn the chlorotic areas in leaves turn red or purple. Common Smut (Ustilago maydis (DC) Cda: The characteristic galls are formed on the infected tissues. Pythium Stalk Rot Disease [P. aphanidermatum (Eds.) The inner tissues also get infected in severe cases. 30-42°C and low soil moisture. Most of the important diseases of maize are foliar and the more common ones are rusts, leaf blights, leaf spots, brown spots, downy mildew, and maize streak virus (MSV). Yield of hybrids with practically nil natural stalk rot incidence have been compared to yields in years when stalk rot is severe. Virus and virus-like diseases. Another technique used is comparing inoculated vs. uninoculated plots. Welcome to BiologyDiscussion! This can lead to reduced growth. The safety and integrity of the food supply are the paramount importance and are among the drivers of safe grain storage. Sclerotia are found to be produced not only on sheaths, leaves and husk leaves but were also observed for the first time on glumes, in cupules, under the pericarp in caryopsis and silk fibres. No alternate host for this disease has been found. Share Your Word File Dari . Contents. Ten downy mildew (DM) diseases are identified on maize. Secondary spread is through airborne conidia. The characteristic symptoms is the blackening of the vascular bundles as black dots on the cut ends of the stalk. The presence of downy whitish to creamy growth usually on the ventral surface of the infected leaves corresponding to- stripes is the most characteristic symptom. This leaf diseases on maize is a fungal disease that occurs in most of South Africa’s maize producing areas. The cobs are poorly filled. The foliar blight disease complex in cool conditions favoured for turcicum leaf blight. Pathogen/Disease description: The fungus infects corn ears through the silks and produces swollen light green growths that later turn white and break open to revel black masses of spores when mature. In severe cases, leaves dry and plants may wilt. Typically, the first sign of stalk rot is plant wilting. Jines (2006) prepared a multiple interval mapping model, including four QTL, accounted for 88% of the variation among average disease ratings. The mycelium develops above and between kernel rows. Fusarium Ear Rot Disease 13. Northern leaf blight (Heirninthosporium turcicum = Exserohilum turcicum) is a major problem in the region with cooler environment like J&K, H.P. This may cause the stalk to appear gray-black. Zoospore germination occurs in the temperatures (15-30°C), with an optimum at 22-25°C. Use only disease resistant hybrids and composites in disease prone areas. Control a Spray with insecticides like vetox 85, and practice crop rotation. The disease can be minimized, using indigenously formulated compound bleaching powder containing 33 per cent chlorine at the rate 10 kg /ha as soil drench at pre-flowering in standing crop. Use resistant varieties. Rhizoctonia solani Kunh is morphologically characterized by features like pale to brown colour of mycelium, branching near the basal septum in young growing hyphal, presence of a construction and formation of a septum in branch near the point of origin, absence of clamp connections, sclerotia of un-differentiated texture, young multinucleate hyphal cells with a prominent septal pore apparatus and rapid growth rate. 10. 1 Bacterial diseases. Maize Field Guide Maize Crop Development, Pests and Diseases. Stem galls result in loss in yield and bending of the stalk. The galls are light coloured in the beginning and later on become dark. 4 Virus and virus-like diseases. Downy Mildews Disease 4. Sporangia and spore of the pathogen are disseminated by wind, rain and animals. The magnitude of grain loss may reach as high as 100 per cent if the ear rot phase of the disease predominates. Disease incidence varying from 2 to 80 per cent was observed affecting maize crop severely in Korea during previous two crop seasons. Galls on the ear usually destroy it to a large extent while large galls above the ear cause much greater reduction in yield than do galls below the ear. Maize mosaic virus and other maize virus diseases in the islands of the Western Indian Ocean. Control of foliar blight disease can be achieved using host resistance which has been quite successful, chemical control is also feasible, it becoming profitable on high volume materials like popcorn, sweet corn, baby corn or seed crop. Diseases of Maize Downy mildew/Crazy top Sorghum downy mildew - Peronosclerospora sorghi Phlippine downy mildew - Peronosclerospora philippinensis Crazy top - Sclerophthora macrospora Symptoms The most characteristic symptom is the development of chlorotic streaks on the leaves. Later on these pustules turn black due to formation of teleutospores. Disease Symptoms and Severity on Maize Ears. They are brittle, usually two celled constricted at the septum and born on the short 10-30 pm persistant brownish pedicels one fourth length of the spore. Stalk rot is first recognized when the plants first lodge but do not break over. Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. TOS4. 3 Nematodes, Parasitic. The black powdery masses are the chlamydospores of the fungus. Black Bundle Disease and Late Wilt:. A mild sweet... 2. Kernels infected late in the season develop whitish streaks on the grains. Fungi associated with the cob rots are— Aspergillus flavus, Fusarium species, Gibberella zeae, Penicillium etc. The natural disease pressure every winter cycle allowed for the selection of disease resistant germplasm. However, the magnitude of grain loss may reach as high as 100% if the ear rot phase of the disease predominates. It is a major disease in the mountainous areas and in the deep hillside areas of Rajouri and Poonch districts, especially in the cool and shady environment of intermediate zone of J&K. Water soaked, brown lesions appear on roots which turn brown later on. Sugarcane Downy Mildew (Sclerosspora sacchari Miyake): The characteristic symptom is the development of long, rather broad chlorotic stripes along almost entire length of the leaves. The infected tissues are at first soft but later on they turn into dry mass of shredded fibers. Field should be cleaned off the trash after harvest. MAIZE DISEASES I. The light, shiny membrane ruptures and dry black spores masses are exposed. Zinc deficiency predisposes plants to infection. Head Smut [Sphacelothica reilina (Kunh.) The symptoms are more common on the leaf sheaths than on the laminate. “The term “stalk rot” is often used to include stalk breakage, stalk lodging, premature death of plants and occasionally root lodging. It is also expected that the spread of the disease to new locations could pose a major threat to maize cultivation, as this is considered to be the most destructive amongst the rust of maize. It is externally seed borne and soil borne. The affected plants may be malformed with undeveloped tussles and ears. The major approach adopted has been the utilization of host resistance. Although, the disease may be externally seed-borne, the major source of infection is soil-borne inoculums. Primary infection invariably occurs on lower proximate to the ground level. Both hybrids and V composites possessing resistance have been released. Seed application (Apron 35 W.P., at the rate 0.25 per cent (2.5 g/kg seed) in a slurry is most economical and total control can be obtained. Losses from corn smut are highly variable from one location to another and may range from a trace upto 35 per cent or more in localized areas. Ashby]. All the Peronoslerospora incited diseases are of old world origin, three of which namely, P. sorghi, P. sacchari, and P. phillipinensis are of common occurrence in India. This disease has been considered as one of the major diseases of maize. The disease lesions are characterised by the presence of alternate bleached areas or zones that are initially water soaked and narrow, purple brown bands oriented perpendicular to long axis of leaves or leaf sheaths. Nematodes, Parasitic. Viruses are the most mysterious disease agents affecting both plants and animals, and hence the limited amount of studies and where there is the least information on their incidence and economic effects. The information is required to both pathologists and breeders to understand the complexity of the viral pathotypes, both in their genome and their evolution, to be considered when selecting for stable resistance to their pathogens. The disease symptoms appear only near maturity. The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, 167-181. The uredospores constitute both primary and secondary inoculum and are carried to maize plants by wind or on infected materials. Banded Leaf and Sheath Blight (BLSB) of Maize- Discussed ! This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. Infections can also occur through wounds on stalks and leaves. Its uses are continuously increasing globally as important livestock, poultry feed and by industrial sectors. In the initial stages, the lesions start developing on lower leaves as narrow chlorotic or yellowish stripes, 3-7 mm wide but variable in length. What is the reserve food material in red algae? Symptoms start with lesions usually noticed on the bottom leaves first, which then spread to upper leaves when spores are released. Banded Leaf and Sheath Blight (BLSB) Disease: It was first reported from Sri Lanka. There nature is often complex as a number of fungi, nematodes and sometimes bacteria are involved in causation of the disease(s). Share Your PPT File. Maize Dwarf Mosaic Virus (Sugarcane Mosaic Virus, Transmitted by Aphids, Myzus persicae): Early infested plants produce long chlorotic streaks along the veins at the base of the leaf lamina. The colour of the stripe is whitish in early stage which changes to dark brownish yellow in very late stages. The infection goes through silk to the maize seed/grains but remained latent and cause decay at the time of maturity in the form of cob rot/ear rot, sometimes the grain remain infected but does not show any symptoms even at the time of maturity. In paired plant technique, grain yields of adjacent diseased and healthy plants are compared. The disease is favoured by high temperature i.e. Rust pustules appear on the above ground plant parts especially on leaves. Fungicidal Management: Metalaxyl (Ridomil) can be applied to seed, in furrows as granules or sprayed on foliage. On the other hand the loss of grains is increasing with the increase of food production due to poor and improper storage as well as the pre harvest fungi associated with maize. Subsequently adjacent planted fields can be severely damaged. Smut Diseases 2. The cob formation either does not take place or the grain formation is partial or wholly affected. (2) Grasshoppers: They eat up the leaves and other soft vegetative parts of the plant. Though it was considered a disease of minor importance till it appeared in an epidemic form in the foot hills region of Himalayas especially in the district of Mandi in Himachal Pradesh. Maize has several major disease issues; thus, breeding multiple disease resistant (MDR) varieties is critical. Erwinia Stalk Rot (Erwinia chrysanthemi pv. Crops are hosts to numerous plant pathogenic microorganisms. Avoiding of water logging and proper drainage also helps in reducing disease incidence. The Peronoslerospora spp are seed borne in nature. Raid (1988) found that even if infection comes as late as after anthesis, losses occur and the pathogen may cause heavy losses when the environmental conditions are conducive for disease development. These changes in technology are bringing along an increase in problems, specially insects and diseases, that were not previously considered problems of any significance. Galls are first covered with a membrane that soon breaks open to expose a powdery mass and the vascular bundle of the host. Telia often appear in circles around the uredial pustules. Pythium Stalk Rot Disease 8. Among the rust diseases in maize Polysora rust or tropical rust or southern corn rust (Puccinia polysora Underw) is an important disease in tropical areas. iv. ii. Cobs are not filled well. Caucasians disease can be avoided by the selection of seed varieties that are resistant P. maydis, destroy infected plants, planting according to season, and crop rotation. Since only few plants are affected in a field it is possible to locate and destroy the infected ears before they shed the ears. like KH-517, KH-612, GS-2 etc. 16. This group of disease is broadly divisible into two categories, viz., pre-flowering and post-flowering types. In this study, we wanted to evaluate the potential of Bacillus amyloliquefaciens as biocontrol agent to fight some newly isolated endemic fungal pathogens infesting maize. It occurs in many parts of the world, and it is a recent introduction in the peninsular India in 1991 (Karnataka and Tamil Nadu during rainy season and Coastal districts of Andhra Pradesh during winter) on certain maize cultivars in Mysore distric. These studies clearly indicate that a few major loci undergrid general resistance to polysora rust in tropical maize germplasm. Total grain weight on stalk rot affected plants is less than the weight on healthy plant. Losses to the extent of 11-40 per cent were reported while evaluating 10 different varieties of maize. For the first time was reported from Srilanka under the name ‘Sclerotial’ disease. These field fungi infect the cobs either immediately or before harvest. These studies, however, are confounded by natural infection in uninoculated plots, and by the fact that inoculation does not exactly duplicate the natural stalk rot condition. This is a common disease in warm and dry areas. zeae Victoria, Arboleda and Munoj): It is one of the most important disease of maize in tropical countries. (With Methods)| Industrial Microbiology, How is Cheese Made Step by Step: Principles, Production and Process, Enzyme Production and Purification: Extraction & Separation Methods | Industrial Microbiology, Fermentation of Olives: Process, Control, Problems, Abnormalities and Developments. The teliospores are dark brown, smooth angularly ellipsoid or oblong, rounded at both the ends and 18-27 x 29-41 µm. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? Losses in grain yield showed a high positive correlation with premature death of plants and disease index. Losses due to stalk rot may occur in the following three ways: i. Systemic fungicides usually act on but one site in the fungus, whereas protective (non-systemic) fungicides act on several sites. A definite relationship of disease development with rainfall pattern in different region ns has been mapped. As the galls are enlarging they appear light coloured or almost white. Infection usually begins with a few plants in early sown fields. At first, the upper leaves show signs of wilting. Green silks are relatively resistant. Other important symptoms of this disease are a reddening or purpling of the leaves and stalks, lesions on basal portion of the stalk, multiple ear formation at node and excessive tillering. Stalk Rot Disease 6. In order to diagnose diseases correctly, a diagnostic method based on hyperspectral imaging technology for Curvularia lunata and Aureobasidium zeae was proposed. Do eukaryotic cells have restriction endonucleases? Greatest loss results from systemic infection. Save my name, email, and website in this browser for the next time I comment. iii. Post flowering stalk rot: Cephalosporium wilt (Black bundle disease and late wilt) Causal … Control Pests of Maize In cloudy weather, the growth is profuse and can be seen. Resistance has been identified on the basis of natural incidence only and methods to induce artificial disease development in the field through resisting sporangia are to be worked out. Internal mycelium is inactivated by drying seed to 20 per cent or less moisture and storing for about 3 weeks. Corn also requires ample space as it grows large in size a… Before sharing your knowledge on this site, please read the following pages: 1. Black Bundle Disease 11. The problem with such mentality, the incidence of these diseases continues to increase, especially under the present actively changing circumstances in agriculture when new germplasm is almost freely moving throughout all environments, agronomic practices are changing, and there is a conspicuous expansion of area where maize is being grown due to an increased demand. Common Smut. Brown Spot Disease 5. Singh and Sharma (1979) estimated 40.5% loss in grain yield with 71% disease index. If conditions are favourable and the disease is present in the host plant then it will start to develop and take over the plant. The affected plants topple over but do not die for upto 2 weeks after attack. The secondary infection take place by means of uredopustules which are wind born disseminated to the neighboring plants. Ardon (1988) recorded yield loss up to the tune of 45% especially on late planted maize however, Frederekson (1990) reported 60% loss in grain yield. It has occurred in severe form on Pioneer H-3054 and caused 25-35 per cent yield losses during Kharif-2005 in Manialdara region of Rajouri district. Charcoal Rot Disease [Macrophomina phaseolina (Mubl.) Disease develops rapidly in warm weather and uredospores comprise both primary and secondary inoculum. Stalk rots are the most serious and widespread group of the diseases in maize. In recent years the disease outbreaks have occurred in more countries and have assumed epidemic dimensions. It is important that, where a disease outbreak is feared, spraying should be undertaken at an early stage of crop growth, i.e. Severe losses due to this disease can occur especially if infection occurs early. However, in areas of low rainfall, disease may be severe only when continuous spell of shower and cloudiness for a few days accompanied by about 25°C temperature are prevalent. If only the parts of the tassels and ears are converted into galls, the floral bracts turn into leafy structures. SINCE 1856 In: Gordon DT, Knoke JK, Nault LR, Ritter RM, eds. Of the 61 diseases of maize recorded so far, 15 and one nematode problem, are considered to constitute the major constraints limiting production. Source of primary inoculum includes collateral cultivated and wild hosts, infected volunteer plants, kitchen gardens and certainly oospores, where formed. Name the types of nitrogenous bases present in the RNA. Distinct symptoms of GLS are … Apart from causing severe damage to the crop, it can also produce a potentially fatal mycotoxicosis in cattle and sheep. In India, losses in grain yield have been estimated in the range of 23.9 to 31.9%. 2 Fungal diseases. The yield losses depend on susceptibility of the host, spread of the disease and environmental conditions prevailing in the growing season. Disease cycle The primary source of infection is through oospores in soil and also dormant mycelium present in the infected maize seeds. iii. It is mainly soil borne. In initial stage, leaves become gray, ears drop and outer rind of lower stalk may turn brown. What are the three important components of biodiversity? The experimental leaves were inoculated in vivo, and a … One of the most important requirements for growing corn is a high quality soil which is deep, fertile and well-draining with a pH between 6.0 and 6.8. In present scenario, the trade among the developing countries is expanding; hence quality of the produce is becoming a major concern. A yield loss of 63 per cent was recorded in the tarai areas of U.P. Answer Now and help others. When RH drop 50 per cent or below, no rot develop in the stalks. Brown Stripe Downy Mildew (BSDM) Disease: It has been most severe in U.P., H.P., southern Rajasthan, Punjab, hilly part of W.B., J&K especially in areas that receive 100-200 cm of rains. ii. Disease symptoms have been observed only on leaves. The growth of the fungus can be seen on both the surfaces of the stripes. Cultural Practices: Several cultural practices reduce severity of diseases. The stalks and ears may also be affected which emit an offensive odour. As the disease progress, infected kernel becomes covered with a powdery/cottony pink mild growth. Ears may rot or even the ears may not be formed. Demand for maize in both national and international market is high.
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