Singh and Sharma (1976) estimated 40.5 per cent loss in grain yield with 71 per cent disease index. 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. 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. Grow resistant/moderately resistant var. SEEDING . 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. The stripes extend in parallel fashion, have well defined margins and are delimited by veins. Development on lower surface is more as compared to upper surface. Banded Leaf and Sheath Blight (BLSB) of Maize- Discussed ! The plants are pale green, stunted and show mosaic mottling on the leaves. Now it has become increasingly severe and assumed epidemic proportions in the next two decades. 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. Infected plants do not... 3. when it is not more than 30 days old (knee-high stage). These studies clearly indicate that a few major loci undergrid general resistance to polysora rust in tropical maize germplasm. Proceedings of the International Maize Virus Disease Colloquium and Workshop, August 2-6, 1982. Water soaked, brown lesions appear on roots which turn brown later on. 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 experimental leaves were inoculated in vivo, and a … Neil Groom, technical director for maize seed supplier Grainseed looks at … ii. 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. Ears may rot or even the ears may not be formed. Kernels infected late in the season develop whitish streaks on the grains. The affected plants may be malformed with undeveloped tussles and ears. Brown Spot Disease: This disease mainly occurs in sub-tropical and intermediate areas. 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. Curvularia lunata and Aureobasidium zeae are the main leaf diseases of maize in Northeast China. Soil temperature of 28-32°C favour disease development. 3 Nematodes, Parasitic. = Gibberella moniliforme (Sheld.) Diplodia ear rot is a notable maize disease in South Africa. Infected maize leaves become chlorotic and dry. Since only few plants are affected in a field it is possible to locate and destroy the infected ears before they shed the ears. 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. Spraying mixture solution containing 50 g Agrimycin and 2 kg of ceresan wet/ha will also control the disease. 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. Sun drying of seeds lead to inactivation of mycelium present in seed and also reduce moisture levels. This can lead to reduced growth. The growth of the fungus can be seen on both the surfaces of the stripes. They may coalesce and thereby produce scorching or drying of the leaves. Seed treatment with captan or thiram at the rate 3 g/kg seed. Sow the seed before rainy season begins. However, they do not appear to present a problem. Later, these chlorotic stripes turn brown and give a burnt appearance to the leaves. Seed treatment with carbendazim or benlate at the rate 2 g/kg seed. 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. The cob formation either does not take place or the grain formation is partial or wholly affected. At RH of 70 per cent lower, the disease development is negligible or absent. SINCE 1856 5 References. Head Smut [Sphacelothica reilina (Kunh.) Save my name, email, and website in this browser for the next time I comment. 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. Crops are hosts to numerous plant pathogenic microorganisms. Grain losses have been estimated in the range of 23.9-31.9 per cent in ten cultivars. Share Your Word File 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. Resistant lines normally show small chlorotic or necrotic flecks with no sporulation. The cobs are poorly filled. at the rate 0.25 per cent is a good safeguard against any possible seed-borne infection. The primary source of inoculums are sclerotia in the soil and grass hosts that grow in the vicinity of maize crop. Bacterial diseases. The hyphal masses on ears produce a caking effect and cement the husk leaves as well as styles (silk fibers) together. Common Smut (Ustilago maydis (DC) Cda: The characteristic galls are formed on the infected tissues. Nematodes, Parasitic. In: Gordon DT, Knoke JK, Nault LR, Ritter RM, eds. 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. The yield losses depend on susceptibility of the host, spread of the disease and environmental conditions prevailing in the growing season. 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. Low temperature is favourable for infection. Potchefstroom Bacterial diseases of maize can cause headaches for producers. Green silks are relatively resistant. Later on these pustules turn black due to formation of teleutospores. Banded Leaf and Sheath Blight (BLSB) Disease: It was first reported from Sri Lanka. No need to register, buy now! 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. avenae Manns (syns. The individual flowers may be infected on tassel and even through individual flower parts may be transformed into galls. Maize aphid: Attacks are on leaves as a black fungal growth (called sooty mold) often occurs on the honeydew secreted by aphids. Share Your PDF File Both hybrids and V composites possessing resistance have been released. i. Zinc deficiency predisposes plants to infection. Rust pustules appear on the above ground plant parts especially on leaves. Once the primary infection becomes established, its spread is possible through the agency of sporangia. Ashby]. 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. Distinct symptoms of GLS are … The characteristic reddening of the internal tissues are discernible when affected plants are longitudinally split open. i. Rust (Puccinia sorghi), the symptoms are patches of brown to orange blotches on the upper leaf surface. Ultimately the entire plant dries up. 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. ii. Avoid water stress after flowering of the plant. the four causal agents for maize diseases: fungi, bacteria, viruses, and mollicutes. 2 and SSR markers closely linked to this locus. A major gene on chr. 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. In some cases the red streak may also be observed. This results in reduced grain quality and potential dockage when the grain is marketed. The most common pathways is infection via silk channel. 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. Thus in the former case only one change in the fungus is required to develop tolerance.Treatment of seed with apron 35 w.p. 10. Maize has several major disease issues; thus, breeding multiple disease resistant (MDR) varieties is critical. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? The galls are light coloured in the beginning and later on become dark. Sporangia are produced at low temperature (20-22°C), while oospores are formed at high temperature. Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. Fitzp. Some times the susceptible maize genotypes got infected with Aspergillus sp. Virus Diseases 3. 5. 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. The light, shiny membrane ruptures and dry black spores masses are exposed. 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. The severity of the disease is influenced by temperature and moisture. THE FUTURE . The major diseases are: four foliar diseases, two pre‐flowering and three post‐flowering stalk rots, four downy mildews and two sheath diseases. Disclaimer Copyright, Share Your Knowledge Stalk Rot Disease 6. Symptoms start with lesions usually noticed on the bottom leaves first, which then spread to upper leaves when spores are released. Disease symptoms have been observed only on leaves. At first, the upper leaves show signs of wilting. In present scenario, the trade among the developing countries is expanding; hence quality of the produce is becoming a major concern. Planting the crop on ridges rather than in flat soil is recommended. Results and Discussion. Biology, Plant Pathology, India, Cereals, Maize, Diseases, Diseases in Maize. ii. 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. Sporangial production and infection require a film of moisture for 12-96 hours. Avoiding of water logging and proper drainage also helps in reducing disease incidence. Fusarium Stalk Rot [Fusarium moniliforme Sheld. The Pathogen is an obligate parasite and cannot be grown in artificial media. 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. Stem galls result in loss in yield and bending of the stalk. iii. Yield of hybrids with practically nil natural stalk rot incidence have been compared to yields in years when stalk rot is severe. Image courtesy of, PEST AND DISEASES OF YAM (Dioscorea spp. 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 … 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. Charcoal Rot Disease 10. Most diseases covered are economically significant or have the potential to become so. Privacy Policy3. Losses also occur with ear rot as a results of the ear on lodged plant coming in contact with soil. 1 Bacterial diseases. Virus and virus-like diseases. The foliar blight disease complex in cool conditions favoured for turcicum leaf blight. Use resistant varieties. A yield loss of 63 per cent was recorded in the tarai areas of U.P. ), 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. 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. They could be shaken off or killed chemically. Fungus: Ustilago maydis. 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. They also stated that the maturity and Polysora rust rating were slightly correlated, but QTL for the two traits did not co-localize. This group of disease is broadly divisible into two categories, viz., pre-flowering and post-flowering types. 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. Secondary spread of disease is by contact of infected leaves with parts of adjoining healthy plants. This disease is air born. i. 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. Here is a list of seventeen major diseases that are found in maize: 1. Galls are first covered with a membrane that soon breaks open to expose a powdery mass and the vascular bundle of the host. This disease has been considered as one of the major diseases of maize. Aspergillus Ear Rot Disease and Others. Information supplied by COLEACP to be found at In young seedlings the plants dry up in the early stage of the growth. In the adult plants the symptoms are not visible till maturity. It is important that, where a disease outbreak is feared, spraying should be undertaken at an early stage of crop growth, i.e. The Peronoslerospora spp are seed borne in nature. Because losses due to stalk rot may occur in several ways, yield loss estimates are difficult to obtain. Key to maize ratings (1) End use This may cause the stalk to appear gray-black. Secondary spread by basidiospores has not been observed in maize crop. These are maize mosaic virus I, maize mosaic (a strain of sugarcane mosaic virus) and vein enotion. 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. 15. The natural disease pressure every winter cycle allowed for the selection of disease resistant germplasm. The uredospores constitute both primary and secondary inoculum and are carried to maize plants by wind or on infected materials. Contents. It is caused by incited by Thanatephorus sasakii (Shirai) Tu & Kimbro; anamorph Rhizoctonia solani f.sp. Smut Diseases 2. Why does plant cell possess large sized vacuole? Jines (2006) prepared a multiple interval mapping model, including four QTL, accounted for 88% of the variation among average disease ratings. Of the many foliar blight diseases occurring in India, three may be considered important based on geographical distribution and yield loss potential. Cultural Practices: Several cultural practices reduce severity of diseases. Brown Spot Disease 5. 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. ii. For the first time was reported from Srilanka under the name ‘Sclerotial’ disease. The disease is favoured by high temperature i.e. Ears frequently abort and are replaced by leafy buds. These types of studies are confounded by year-to-year in average yield. The gall may appear on the stem, leaves, axillary’s buds and parts of the male flower. 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. Highly resistant genotypes have smaller uredosori than the moderately resistant or susceptible ones. 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 damage is most common at or near the tip of the ear; silk infection is favoured by high night and day temperature. Control Pests of Maize Downy Mildews Disease 4. Maize varieties. Apart from causing severe damage to the crop, it can also produce a potentially fatal mycotoxicosis in cattle and sheep. The leaf infection results in long, chlorotic stripes with downy fungal growth. Huge collection, amazing choice, 100+ million high quality, affordable RF and RM images. The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, 167-181. The tassel is partly or wholly converted into smut spores. Internal mycelium is inactivated by drying seed to 20 per cent or less moisture and storing for about 3 weeks. 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. 30-42°C and low soil moisture. Source of primary inoculum includes collateral cultivated and wild hosts, infected volunteer plants, kitchen gardens and certainly oospores, where formed. Do eukaryotic cells have restriction endonucleases? If only the parts of the tassels and ears are converted into galls, the floral bracts turn into leafy structures. Severe losses due to this disease can occur especially if infection occurs early. Air born spores present on residues can land on corn silks when it turns dark brown. 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. TOS4. 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. The affected plants topple over but do not die for upto 2 weeks after attack. Of the 61 diseases of maize recorded so far, 15 and one nematode problem, are considered to constitute the major constraints limiting production. In true sense, it is decay of the internal pith tissues of the stalk. What are the three important components of biodiversity? Symptoms seen on corn include leaf lesions, discoloration (), and foliar blight.. i. The characteristic symptoms is the blackening of the vascular bundles as black dots on the cut ends of the stalk. The resulting diseases cause important losses in production both in crop and after harvest. 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. Stalk rot, ear rot, kernel rot can occur in infected tissue although many times infected tissue have no symptoms. At the Regional Agricultural Research Station, Rajouri and MBRSS, Poonch, it was moderate to high. In this study, we evaluated a disease … Systemic fungicides usually act on but one site in the fungus, whereas protective (non-systemic) fungicides act on several sites. The inner tissues also get infected in severe cases. In severe cases, leaves dry and plants may wilt. The major approach adopted has been the utilization of host resistance. 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. Although, the disease may be externally seed-borne, the major source of infection is soil-borne inoculums. 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. This has been found to be prevalent in the several states and the incidence ranges from 2.2 to 10.6 per cent. 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. (2) Grasshoppers: They eat up the leaves and other soft vegetative parts of the plant. Harvest is slowed if stalk rot is severe and losses also occur due to time loss during harvest. 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. Zoospore germination occurs in the temperatures (15-30°C), with an optimum at 22-25°C. It is mainly soil borne. The symptoms are more common on the leaf sheaths than on the laminate. A major QTL located on the short arm of chromosome 10, explained 83% of the phenotypic variation, with the NC300 allele carrying the resistance. Field should be cleaned off the trash after harvest. Bacterial Stalk Rot:. 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 presence of Polysora rust in the peninsular India, particularly in states like Karnataka, could have an adverse impact on maize production. If conditions are favourable and the disease is present in the host plant then it will start to develop and take over the plant. 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. A tan sooty black, greenish or greenish yellow mold grows on and between kernels. Fungicidal Management: Metalaxyl (Ridomil) can be applied to seed, in furrows as granules or sprayed on foliage. The disease caused drastic reduction in grain yield-to the tune of 97 per cent and exhibited a direct correlation with other yield parameters. South India especially in TN and Karnataka have been reported epidemic at various times. Total grain weight on stalk rot affected plants is less than the weight on healthy plant. Sow the resistant varieties like GS-2 and Ganga-101 which are comparatively resistant. In this, the problem in diseased plants have much less kernels than on healthy plants. Pythium Stalk Rot Disease 8. With the growing age of plant, leaves in the whorl become chlorotic and in turn the chlorotic areas in leaves turn red or purple. This disease mainly occurs in sub-tropical and intermediate areas. A fungicide application is useful when pustules first appear on the leaves. On maize the disease was first recorded from Sri Lanka under the name ‘sclerotial disease’. The magnitude of grain loss may reach as high as 100 per cent if the ear rot phase of the disease predominates. iii. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. Cob Rots Disease 12. As the disease progress, infected kernel becomes covered with a powdery/cottony pink mild growth. Based on the work carried out the management strategies for the Polysora rust is given below: i. There seems to be no controversy about soil borne of the disease.
2020 diseases of maize