The specks elongated to form fine discontinuous stripes. When RH drop 50 per cent or below, no rot develop in the stalks. 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. This disease usually affects maize grown in the tropics to moderate. i. Fusarium Stalk Rot [Fusarium moniliforme Sheld. Another study reported in a different genetic background, a QRL (Quantitative resistant locus) to P. polysora on chr. 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. Grow resistant/moderately resistant var. The gall may appear on the stem, leaves, axillary’s buds and parts of the male flower. The stalks and ears may also be affected which emit an offensive odour. Maize varieties. South India especially in TN and Karnataka have been reported epidemic at various times. Control a Spray with insecticides like vetox 85, and practice crop rotation. Common Smut (Ustilago maydis (DC) Cda: The characteristic galls are formed on the infected tissues. Systemic fungicides usually act on but one site in the fungus, whereas protective (non-systemic) fungicides act on several sites. They may coalesce and thereby produce scorching or drying of the leaves. The experimental leaves were inoculated in vivo, and a … THE FUTURE . However, the magnitude of grain loss may reach as high as 100% if the ear rot phase of the disease predominates. Before sharing your knowledge on this site, please read the following pages: 1. Fusarium Ear Rot Disease 13. The cob formation either does not take place or the grain formation is partial or wholly affected. Distinct symptoms of GLS are … 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. There nature is often complex as a number of fungi, nematodes and sometimes bacteria are involved in causation of the disease(s). This disease has been reported in Kliarif season in areas having temperature ranging 30-35°C and RH (relative humidity) 80-100 per cent. These changes in technology are bringing along an increase in problems, specially insects and diseases, that were not previously considered problems of any significance. Both hybrids and V composites possessing resistance have been released. At the Regional Agricultural Research Station, Rajouri and MBRSS, Poonch, it was moderate to high. 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). 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. The symptom appear at the lower node and may remain confined at one or two internodes only. Contents. In India, the disease was first recorded from Tarai region of Uttar Pradesh in 1960. On maize the disease was first recorded from Sri Lanka under the name ‘sclerotial disease’. No need to register, buy now! A mild sweet... 2. Of the 12 diseases recorded so far, Pythium stalk rot (P. aphanidermatum) and bacterial stalk rot (Erwinia chrysanthemi pv. Development on lower surface is more as compared to upper surface. Acidovorax avenae (Manns) Willems et … Stalks often rot at the first, internode above the soil level and become soft and brown. Head Smut [Sphacelothica reilina (Kunh.) Most diseases covered are economically significant or have the potential to become so. Melching (1975) reported yield loss up to 37% due to P. polysora and rated this disease as the most destructive among the three rusts of maize. Maize mosaic virus and other maize virus diseases in the islands of the Western Indian Ocean. At this stage drying of top leaves from tips begin showing water scarcity. Black Bundle Disease (Cephalosporium acremonium Corda): Banded Leaf and Sheath Blight (BLSB) Disease, The best answers are voted up and rise to the top. There seems to be no controversy about soil borne of the disease. 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. A major QTL located on the short arm of chromosome 10, explained 83% of the phenotypic variation, with the NC300 allele carrying the resistance. Cultural Practices: Several cultural practices reduce severity of diseases. This rot caused by Aspergillus spp. Bacterial diseases. High disease incidence is linked with irrigation by sewage water, it is particularly favoured by high temperature (28°C and above) and the high ambient moisture which commonly prevails in the most of the maize growing areas 3 to 4 week after sowing. iii. Banded Leaf and Sheath Blight (BLSB) Disease: It was first reported from Sri Lanka. It is … Now it is present in J&K, H.P., U..P, M.P., Haryana, Punjab, Rajasthan, W.B., Meghalaya and Assam. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. Stalk rots are the most serious and widespread group of the diseases in maize. Oospores remain viable for at least three years and this viable oospores material constitutes the main source of inoculums. This leaf diseases on maize is a fungal disease that occurs in most of South Africa’s maize producing areas. Downy Mildews Disease 4. Post flowering stalk rot: Cephalosporium wilt (Black bundle disease and late wilt) Causal … MAIZE DISEASES I. The primary source of inoculums are sclerotia in the soil and grass hosts that grow in the vicinity of maize crop. Punjab, Madhya Pradesh, Rajasthan, Bihar, West Bengal, Sikkim, Meghalaya, Assam and Odisha. 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. Of the 61 diseases of maize recorded so far, 15 and one nematode problem, are considered to constitute the major constraints limiting production. Infection follows some form of injury, bird damage, feeding of corn borers. Seed treatment with captan or thiram at the rate 3 g/kg seed. and infection often follows drought stress and damage done by corn, earworms and corn borer and other insects. In severe cases, leaves dry and plants may wilt. Save my name, email, and website in this browser for the next time I comment. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. It is externally seed borne and soil borne. sasakii Exner, has become increasingly severe and economically important disease of maize during last two decades or so. The hyphal masses on ears produce a caking effect and cement the husk leaves as well as styles (silk fibers) together. Rain drizzle or even heavy dews allow disease formation. 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. Teliospores of P. polysora are rare and are not known to be germinated therefore they are unimportant in disease cycle. What is the reserve food material in red algae? 30-42°C and low soil moisture. 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. However, Zummo (1988) reported that heavy losses may occure due to this disease if infection occurs an early stages. ii. | Plant Diseases, Diseases and Management of Grain Smut | Plant Diseases, Effects of M. Grisea on Plants | Plant Disease. i. Plants are weak and those with rotted stalks always have rotted roots. A tan sooty black, greenish or greenish yellow mold grows on and between kernels. 5 References. They could be shaken off or killed chemically. Yellow peach moth is a minor and irregular pest of maize in Queensland. There are a multitude of maize varieties available. ii. 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. However, they do not appear to present a problem. 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 … Seeds with less than 15 per cent moisture content produce healthy plants. Sporangia and spore of the pathogen are disseminated by wind, rain and animals. 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. Disease Symptoms and Severity on Maize Ears. 16. ii. Another component of yield loss is that plants with stalk rot may lodge and not be harvested with mechanical equipment. The disease was earlier reported as a minor disease on maize. iii. Since only few plants are affected in a field it is possible to locate and destroy the infected ears before they shed the ears. Ears may rot or even the ears may not be formed. Bacterial Stalk Rot:. (2) Grasshoppers: They eat up the leaves and other soft vegetative parts of the plant. In order to diagnose diseases correctly, a diagnostic method based on hyperspectral imaging technology for Curvularia lunata and Aureobasidium zeae was proposed. when it is not more than 30 days old (knee-high stage). 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 highest disease intensity i.e. In: Gordon DT, Knoke JK, Nault LR, Ritter RM, eds. 2 Fungal diseases. There are two fungal pathogens that cause GLS: Cercospora zeae-maydis and Cercospora zeina. 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. 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. (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 affected plants topple over but do not die for upto 2 weeks after attack. A fungicide application is useful when pustules first appear on the leaves. This disease has been considered as one of the major diseases of maize. What are the general characters of bryophytes? at the rate 0.25 per cent is a good safeguard against any possible seed-borne infection. The developing mycelium between the thin walled cells induces hypertrophy. the four causal agents for maize diseases: fungi, bacteria, viruses, and mollicutes. Sow the resistant varieties like GS-2 and Ganga-101 which are comparatively resistant. Nematodes, Parasitic. The yield losses depend on susceptibility of the host, spread of the disease and environmental conditions prevailing in the growing season. No alternate host for this disease has been found. 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. Common Names of Plant Diseases - Diseases of Corn or Maize...Gary P. Munkvold, collator (last update: 8/27/17) BACTERIAL DISEASES Bacterial leaf blight Pseudomonas avenae Manns subsp. In paired plant technique, grain yields of adjacent diseased and healthy plants are compared. Planting the crop on ridges rather than in flat soil is recommended. Because losses due to stalk rot may occur in several ways, yield loss estimates are difficult to obtain. Use only disease resistant hybrids and composites in disease prone areas. 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. Resistant lines normally show small chlorotic or necrotic flecks with no sporulation. In this, the problem in diseased plants have much less kernels than on healthy plants. It appears with the formation of tassels and ears where partial or complete transformation of the inflorescence into sori may be observed. It is distributed in the entire Himalayan area as also in states of Rajasthan and Karnataka. 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. These field fungi infect the cobs either immediately or before harvest. 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. Losses also occur with ear rot as a results of the ear on lodged plant coming in contact with soil. The foliar blight disease complex in cool conditions favoured for turcicum leaf blight. Rust (Puccinia sorghi), the symptoms are patches of brown to orange blotches on the upper leaf surface. Our mission is to provide an online platform to help students to share notes in Biology. However, it became increasingly severe and assumed epidemic proportions in the next two decades. RFLP markers flanking this locus have been identified. 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. 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. The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, 167-181. The disease symptoms appear only near maturity. Only young plants are susceptible. The symptoms are more common on the leaf sheaths than on the laminate. As the disease is soil borne it starts from the lowest leaf sheath or on leaves that are in contact with soil and travels up to the ear. Harvest is slowed if stalk rot is severe and losses also occur due to time loss during harvest. Air born spores present on residues can land on corn silks when it turns dark brown. Share Your Word File 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. 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. Brown Spot Disease 5. i. Infected plants do not... 3. In this study, we evaluated a disease … The natural disease pressure every winter cycle allowed for the selection of disease resistant germplasm. The magnitude of grain loss may reach as high as 100 per cent if the ear rot phase of the disease predominates. 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. Galls are first covered with a membrane that soon breaks open to expose a powdery mass and the vascular bundle of the host. Infection usually begins with a few plants in early sown fields. Disease development and spread one favoured by dry warm weather. Share Your PPT File. Brewbaker (2005) demonstrated that synthetic MIRSYN3 based on 19 highly resistant inbreeds showed resistance through 6 cycles of recurrent selection. This results in reduced grain quality and potential dockage when the grain is marketed. Virus Diseases 3. Ears frequently abort and are replaced by leafy buds. Based on the work carried out the management strategies for the Polysora rust is given below: i. 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. Black Bundle Disease and Late Wilt:. Crops are hosts to numerous plant pathogenic microorganisms. = Gibberella moniliforme (Sheld.) 1 Bacterial diseases. Severe losses due to this disease can occur especially if infection occurs early. Northern leaf blight (Heirninthosporium turcicum = Exserohilum turcicum) is a major problem in the region with cooler environment like J&K, H.P. 7. Why does plant cell possess large sized vacuole? Pre-Flowering Stalk Rot Disease 7. In present scenario, the trade among the developing countries is expanding; hence quality of the produce is becoming a major concern. iii. The galls are light coloured in the beginning and later on become dark. Here is a list of seventeen major diseases that are found in maize: 1. Oospores have not been implicated as being carried out on kernels surface. Charcoal Rot Disease [Macrophomina phaseolina (Mubl.) iv. Charcoal Rot Disease 10. These types of studies are confounded by year-to-year in average yield. Image courtesy of agrifarming.in, PEST AND DISEASES OF YAM (Dioscorea spp. In areas where rainfall varies from 40-60 cm, disease was observed from trace to low, in 60 to 100 cm rainfall areas it was from low to moderate, but in the areas having more than 100 cm rainfall, maximum disease ratings have been made. 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. 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. The plants are pale green, stunted and show mosaic mottling on the leaves. The light, shiny membrane ruptures and dry black spores masses are exposed. i. Later, these chlorotic stripes turn brown and give a burnt appearance to the leaves. 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. Once the primary infection becomes established, its spread is possible through the agency of sporangia. Of the many foliar blight diseases occurring in India, three may be considered important based on geographical distribution and yield loss potential. Polysora rust is a warm weather disease favoured by wet weather infection and disease development at 12- 27°C temperature. If only the parts of the tassels and ears are converted into galls, the floral bracts turn into leafy structures. Symptoms start with lesions usually noticed on the bottom leaves first, which then spread to upper leaves when spores are released. Kernels infected late in the season develop whitish streaks on the grains. A major gene on chr. SEEDING . Pythium Stalk Rot Disease 8. Do eukaryotic cells have restriction endonucleases? Sporangial production and infection require a film of moisture for 12-96 hours. The characteristic reddening of the internal tissues are discernible when affected plants are longitudinally split open. Diseases of maize 1. Diseases in maize require certain environmental conditions to develop. The most common pathways is infection via silk channel. The growth of the fungus can be seen on both the surfaces of the stripes. 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. Sow the seed before rainy season begins. 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. The symptoms manifest on leaves, sheaths, stalk and ear. Secondary spread by basidiospores has not been observed in maize crop. Disease symptoms have been observed only on leaves. The pathogen infects crab grass. As the leaves are infected by the pathogen, it drastically reduces the total photosynthetic area of the diseased plants, causing reduction in grain yield. These two diseases are similar and difficult to distinguish. Aspergillus Ear Rot Disease and Others. 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. Corn also requires ample space as it grows large in size a… This disease is air born. This disease mainly occurs in sub-tropical and intermediate areas. Use resistant varieties. Corn plants are very heavy feeders and even the most fertile of soils may need to supplemented with nutrients as the plants develop, particularly nitrogen. Symptoms seen on corn include leaf lesions, discoloration (), and foliar blight.. Virus and virus-like diseases. Curvularia lunata and Aureobasidium zeae are the main leaf diseases of maize in Northeast China. Sporangia are produced at low temperature (20-22°C), while oospores are formed at high temperature. Huge collection, amazing choice, 100+ million high quality, affordable RF and RM images. In India, significant loss in maize yield is usually localized to late planted areas. 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. On pulling out the affected plants, rotting of the seeds may be clearly seen. Maize area in the region has increased by 13.2 % between 2006 and 2011 with 86% of the increase in area occurring in China with the displacement of other crops including wheat, rice, and soybean (FAO Stat, USDA/FAS, 2011)• Diseases cause roughly a 12% yield loss across the region, and to meet the demand for maize seen across Asia, breeding for host resistance is a key … This is more destructive disease in the intermediate zone of Jammu region. In India, losses in grain yield have been estimated in the range of 23.9 to 31.9%. Disclaimer Copyright, Share Your Knowledge 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. Share Your PDF File Stalk rot, ear rot, kernel rot can occur in infected tissue although many times infected tissue have no symptoms. The disease kills the plant prematurely after flowering. ii. 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. 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. 5. 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. 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 pathogen over winters as sclerotia and may penetrate roots and lower stems during growing seaspn. Primary infection invariably occurs on lower proximate to the ground level. TOS4. Post-Flowering Stalk Rot Disease 9. Fungicidal Management: Metalaxyl (Ridomil) can be applied to seed, in furrows as granules or sprayed on foliage. Wineland]: The disease appears both on young and adult plants of maize. The Peronoslerospora spp are seed borne in nature. The infected tissues are at first soft but later on they turn into dry mass of shredded fibers. 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. Although, the disease may be externally seed-borne, the major source of infection is soil-borne inoculums. Typically, the first sign of stalk rot is plant wilting. The resulting diseases cause important losses in production both in crop and after harvest. Apart from causing severe damage to the crop, it can also produce a potentially fatal mycotoxicosis in cattle and sheep. 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. When formed on the cob they cause extensive damage. Proceedings of the International Maize Virus Disease Colloquium and Workshop, August 2-6, 1982. Ullstrup (1965) reported a dominant gene of resistance and designated it as Rpp9. 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. Losses due to stalk rot may occur in the following three ways: i. Losses from India and several SE Asian countries have been reported to be as high as 40-60 per cent. Highly resistant genotypes have smaller uredosori than the moderately resistant or susceptible ones. Grey leaf spot (GLS) is a foliar fungal disease that affects maize, also known as corn.GLS is considered one of the most significant yield-limiting diseases of corn worldwide. Losses to the extent of 11-40 per cent were reported while evaluating 10 different varieties of maize. Control Pests of Maize 10. Trichoderma strains obtained from maize cobs displayed typical characteristics of this genus on PDA plates, such as initial growth of white mycelium, soon turning into green, and gray-green colonies, while the reverse side of the culture plates stayed uncoloured or light yellow.Trichoderma ear rot infection is characterized by white … Jines (2006) prepared a multiple interval mapping model, including four QTL, accounted for 88% of the variation among average disease ratings. Cobs are not filled well. Smut Diseases 2. ii. Larvae tunnel into stems or cobs producing masses of webbing and excreta at the tunnel entrance. The final problem with yield loss studies is that the losses are estimated on the basis of hand-harvested yield and do not take into account those losses due to lodging or ear rots. Ashby]. The teliospores are dark brown, smooth angularly ellipsoid or oblong, rounded at both the ends and 18-27 x 29-41 µm. 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. It will consume energy intended for leaf and grain production and ultimately it will suffocate the plant. Demand for maize in both national and international market is high. Pest and diseases in crops Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. 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. Its uses are continuously increasing globally as important livestock, poultry feed and by industrial sectors. 15. As the galls are enlarging they appear light coloured or almost white. Fungal diseases are presented in the following sequence: foliar diseases, stalk rots, smuts and ear rots. In some cases the red streak may also be observed. Sun drying of seeds lead to inactivation of mycelium present in seed and also reduce moisture levels. Disease cycle The primary source of infection is through oospores in soil and also dormant mycelium present in the infected maize seeds. Find the perfect maize disease stock photo. Dari . zeae Victoria, Arboleda and Munoj): It is one of the most important disease of maize in tropical countries. Disease incidence varying from 2 to 80 per cent was observed affecting maize crop severely in Korea during previous two crop seasons. 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. Maize Field Guide Maize Crop Development, Pests and Diseases. Singh and Sharma (1979) estimated 40.5% loss in grain yield with 71% disease index. Resistance of a high order even immunity (CM 103 and CM 104) has been identified and improved released cultivars have not been reported to suffer much from virus diseases. These are designed to eliminate the causal pathogens from a particular area, to significantly reduce primary inoculum or to stimulate growth during the first month after planting. Three viruses occurs on maize in India. A recent increase in the incidence and spread of bacterial leaf streak (BLS) makes it important to understand this disease in order to develop management practices for its control. 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. At first, the upper leaves show signs of wilting. Erwinia Stalk Rot (Erwinia chrysanthemi pv. Low temperature is favourable for infection. The damage is most common at or near the tip of the ear; silk infection is favoured by high night and day temperature. Privacy Policy3. Ten downy mildew (DM) diseases are identified on maize. Singh and Sharma (1976) estimated 40.5 per cent loss in grain yield with 71 per cent disease index. This group of disease is broadly divisible into two categories, viz., pre-flowering and post-flowering types. In recent years the disease outbreaks have occurred in more countries and have assumed epidemic dimensions. The importance of the disease was only realized in early 1970s when an epidemic occurred in warm and humid foot hills area, particularly in the Mandi district of Himachal Pradesh. 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. It is caused by incited by Thanatephorus sasakii (Shirai) Tu & Kimbro; anamorph Rhizoctonia solani f.sp. The inner tissues also get infected in severe cases. SINCE 1856 ), 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. www.kws-uk.com. It differs from common rust (P. sorghi) in pustule size, shape and colour however the most pronounced variation is that it kills the host unlike P. sorghi. Secondary spread is through airborne conidia. iii. The stripes extend in parallel fashion, have well defined margins and are delimited by veins. 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. 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. This results in death or bareness. The major diseases are: four foliar diseases, two pre‐flowering and three post‐flowering stalk rots, four downy mildews and two sheath diseases. Cob Rots Disease 12. Maize aphid: Attacks are on leaves as a black fungal growth (called sooty mold) often occurs on the honeydew secreted by aphids. Disease develops rapidly in warm weather and uredospores comprise both primary and secondary inoculum. As the disease progress, infected kernel becomes covered with a powdery/cottony pink mild growth. 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. Name the types of nitrogenous bases present in the RNA. The presence of Polysora rust in the peninsular India, particularly in states like Karnataka, could have an adverse impact on maize production. Kernels become infected in several ways. Fitzp. The black powdery masses are the chlamydospores of the fungus. These are maize mosaic virus I, maize mosaic (a strain of sugarcane mosaic virus) and vein enotion. Secondary spread of disease is by contact of infected leaves with parts of adjoining healthy plants. 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. Stalk rot is first recognized when the plants first lodge but do not break over. It is known to be present in severe intensity in the states of Himachal Pradesh, Uttar Pradesh, Uttaranchal, Haryana. Fungus: Ustilago maydis. Spraying mixture solution containing 50 g Agrimycin and 2 kg of ceresan wet/ha will also control the disease. The presence of mycotoxin traditionally regarded as indication of poor storage condition, but they may present in grains before coming to storage. Soil temperature of 28-32°C favour disease development. For large scale high volume sprays 1.8-2.6 kg of fungicide in 900-1200 litre of water/ha is recommended, if the plant population is around 56,000/ha. What are the three important components of biodiversity? With the growing age of plant, leaves in the whorl become chlorotic and in turn the chlorotic areas in leaves turn red or purple. Yield of hybrids with practically nil natural stalk rot incidence have been compared to yields in years when stalk rot is severe. avenae Manns (syns. The downy mildew fungi are mostly on alternate hosts and perenate through oospores which falls down in the soil and secondary infection takes place by means of conidia which are wind disseminated. 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. Banded Leaf and Sheath Blight (BLSB) of Maize- Discussed ! iii. Zinc deficiency predisposes plants to infection. Infected maize leaves become chlorotic and dry. The safety and integrity of the food supply are the paramount importance and are among the drivers of safe grain storage. The affected plants may be malformed with undeveloped tussles and ears. The Pathogen is an obligate parasite and cannot be grown in artificial media. The individual flowers may be infected on tassel and even through individual flower parts may be transformed into galls. 4 Virus and virus-like diseases. like KH-517, KH-612, GS-2 etc. In true sense, it is decay of the internal pith tissues of the stalk. The leaf infection results in long, chlorotic stripes with downy fungal growth. 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. 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. Thus in the former case only one change in the fungus is required to develop tolerance.Treatment of seed with apron 35 w.p. Telia often appear in circles around the uredial pustules. Diplodia ear rot is a notable maize disease in South Africa. 66 per cent was recorded in intermediate zone of Jammu region. Pests, weeds and disease in maize crops can severely reduce yield and quality. The pith becomes hollow and white to pale pink mycelial growth may also seen in the cavity thus formed in advance stage of disease development. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? 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. iii. Some times the susceptible maize genotypes got infected with Aspergillus sp. 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. Rust pustules appear on the above ground plant parts especially on leaves. Yield loss may result from premature plant death, thus stopping normal grain fill. At RH of 70 per cent lower, the disease development is negligible or absent. Key to maize ratings (1) End use Water soaked, brown lesions appear on roots which turn brown later on. Zoospore germination occurs in the temperatures (15-30°C), with an optimum at 22-25°C. 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. etc., under conditions favourable for disease development, susceptible materials suffer heavy blightening resulting in premature drying of leaves and lightweight kernels. 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. Subsequently adjacent planted fields can be severely damaged. In young seedlings the plants dry up in the early stage of the growth. ii. The most diagnostic feature of this disease is that the rot is contained mostly to a single basal internode leading to destruction of pith parenchyma and consequent weakening to the stalk. Payak and Sharma (1985) have reported that annually at least 1% of the total grain yield is reduced by BLSB in India. The uredospores constitute both primary and secondary inoculum and are carried to maize plants by wind or on infected materials. at the time of silking. The severity of the disease is influenced by temperature and moisture. In cloudy weather, the growth is profuse and can be seen. 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. Seed treatment with carbendazim or benlate at the rate 2 g/kg seed. The major approach adopted has been the utilization of host resistance. Avoiding of water logging and proper drainage also helps in reducing disease incidence. Maize grown in cooler areas usually contains low amount of mycotoxin. Source of primary inoculum includes collateral cultivated and wild hosts, infected volunteer plants, kitchen gardens and certainly oospores, where formed. 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. The pathogen has the potential of being destructive if infection comes after anthesis. 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. List of maize diseases. iv. The cobs are poorly filled. Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. 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. 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. The disease generally appears at pre-flowering stage in 40-50 day old plants. मक्का के 5 प्रमुख रोग और उनका प्रबंधन 1. What are the different sources of air pollution? Stalk Rot Disease 6. There are no chemical controls available. Another technique used is comparing inoculated vs. uninoculated plots. This may cause the stalk to appear gray-black. Later on these pustules turn black due to formation of teleutospores. The characteristic symptoms is the blackening of the vascular bundles as black dots on the cut ends of the stalk. In the adult plants the symptoms are not visible till maturity. The mycelium develops above and between kernel rows. Three sprays of Dithane M-45 beginning from first appearance of symptoms at 15 days interval can minimize the disease. The spore retain viability for two years. In initial stage, leaves become gray, ears drop and outer rind of lower stalk may turn brown. 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 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). Basic requirements Corn is best grown in warm, tropical and sub-tropical regions as it requires warm soils to develop optimally. Maize lines with small pustules surrounded by chlorotic or necrotic zone were rated as resistant while well developed pustules were considered susceptible. This has been found to be prevalent in the several states and the incidence ranges from 2.2 to 10.6 per cent. “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. Welcome to BiologyDiscussion! 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. Brown Spot Disease: This disease mainly occurs in sub-tropical and intermediate areas. Results and Discussion. Ultimately the entire plant dries up. 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). Charcoal-Rot:. The tassel is partly or wholly converted into smut spores. i. Information supplied by COLEACP to be found at https://pip.coleacp.org. 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 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. This is a common disease in warm and dry areas. It is mainly soil borne. Fungi associated with the cob rots are— Aspergillus flavus, Fusarium species, Gibberella zeae, Penicillium etc. The plants may topple down at this stage. Potchefstroom Bacterial diseases of maize can cause headaches for producers. The basal internodes develop soft rot and give a water soaked appearance. Stem galls result in loss in yield and bending of the stalk. Polysora rust is a warm weather disease favoured by wet weather infection and disease development at temperatures (27°C) and high relative humidity. Biology, Plant Pathology, India, Cereals, Maize, Diseases, Diseases in Maize. Sometimes the stripes coalesce and form yellow bands of the leaves. Losses in grain yield showed a high positive correlation with premature death of plants and disease index. In India, it was first recorded by Ullstrup in the Tarai areas of U.R. Greatest loss results from systemic infection. Its seed borne nature is controversial. Internal mycelium is inactivated by drying seed to 20 per cent or less moisture and storing for about 3 weeks. Presently, the disease is considered as a major disease in India wherever maize is grown in warm and humid conditions. 3 Nematodes, Parasitic. The colour of the stripe is whitish in early stage which changes to dark brownish yellow in very late stages. The secondary infection take place by means of uredopustules which are wind born disseminated to the neighboring plants. 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. Of these, seven are caused by Peronoslerospora species, two by Sclerospora and one by Euclerospora. 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. Pythium Stalk Rot Disease [P. aphanidermatum (Eds.) The choice of variety will depend on market requirements, environmental conditions, whether the crop is irrigated and the level of disease resistance required.Varieties are continually changing so ensure you have up-to-date varietal information. 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. Stripes may also be formed on sheaths, husks, and the stalks. Field should be cleaned off the trash after harvest. It is important that, where a disease outbreak is feared, spraying should be undertaken at an early stage of crop growth, i.e. The disease causes direct losses, resulting in premature death, stalk breakage and ear rot indirect losses by reducing the grain yield. Green silks are relatively resistant. Viral and fungal diseases are recorded as causing mortality of armyworms. 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. Maize has several major disease issues; thus, breeding multiple disease resistant (MDR) varieties is critical. 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. Avoid water stress after flowering of the plant. 2 and SSR markers closely linked to this locus. A yield loss of 63 per cent was recorded in the tarai areas of U.P. Neil Groom, technical director for maize seed supplier Grainseed looks at … Infections can also occur through wounds on stalks and leaves. Round to elongated uredo-pustules are on both the surfaces of the leaf. Common Smut. Now it has become increasingly severe and assumed epidemic proportions in the next two decades. Content Guidelines 2. Black Bundle Disease 11. Answer Now and help others. Fungal diseases. These fungi are responsible for microbial spoilage of the grins and production of mycotoxins in pre- and post harvest stages. The disease is favoured by high temperature i.e. They also stated that the maturity and Polysora rust rating were slightly correlated, but QTL for the two traits did not co-localize. Under certain conditions that are stressful for maize plant as the fungus becomes pathogenic and causes disease. A definite relationship of disease development with rainfall pattern in different region ns has been mapped. This can lead to reduced growth. 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. Philippines Downy Mildew (Sclerospora philippinensis): The symptoms are very old similar to that of sugarcane downy mildew except for intensity of colour of stripes. Mosaic Virus (Mosaic Virus Transmitted by Leafhopper): Small white fleck may occur on one side of the midrib near the base of the young leaf and is usually associated with whitening of veins. Grain losses have been estimated in the range of 23.9-31.9 per cent in ten cultivars. A net work project is going on at Directorate of maize Research on gene pyramiding on Polysora rust and further studies are in progress. For the first time was reported from Srilanka under the name ‘Sclerotial’ disease. ]: 9. The disease is common during rainy season under hot and high soil moisture conditions. Some workers reported this pathogen as seed-borne but it was found later that S. rayssiae var zeae is not seed borne because no disease symptoms were observed in spite of providing ideal conditions to the pathogen grown from infected seeds.

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