The Peronoslerospora spp are seed borne in nature. What are the three important components of biodiversity? Stalk rot is first recognized when the plants first lodge but do not break over. The Pathogen is an obligate parasite and cannot be grown in artificial media. 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. It will consume energy intended for leaf and grain production and ultimately it will suffocate the plant. Fitzp. 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 … 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. The natural disease pressure every winter cycle allowed for the selection of disease resistant germplasm. iv. Maize aphid: Attacks are on leaves as a black fungal growth (called sooty mold) often occurs on the honeydew secreted by aphids. There nature is often complex as a number of fungi, nematodes and sometimes bacteria are involved in causation of the disease(s). Singh and Sharma (1979) estimated 40.5% loss in grain yield with 71% disease index. 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). 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. The primary source of inoculums are sclerotia in the soil and grass hosts that grow in the vicinity of maize crop. In some cases the red streak may also be observed. These field fungi infect the cobs either immediately or before harvest. Later on these pustules turn black due to formation of teleutospores. It is mainly soil borne. at the time of silking. i. 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. Teliospores of P. polysora are rare and are not known to be germinated therefore they are unimportant in disease cycle. A definite relationship of disease development with rainfall pattern in different region ns has been mapped. The gall may appear on the stem, leaves, axillary’s buds and parts of the male flower. Fungal diseases. Infection usually begins with a few plants in early sown fields. 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. What is the reserve food material in red algae? Maize mosaic virus and other maize virus diseases in the islands of the Western Indian Ocean. 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. Welcome to BiologyDiscussion! Control Pests of Maize Infection follows some form of injury, bird damage, feeding of corn borers. iii. Image courtesy of agrifarming.in, PEST AND DISEASES OF YAM (Dioscorea spp. Stalk rots are the most serious and widespread group of the diseases in maize. iii. It is known to be present in severe intensity in the states of Himachal Pradesh, Uttar Pradesh, Uttaranchal, Haryana. www.kws-uk.com. 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. However, they do not appear to present a problem. 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. Yield of hybrids with practically nil natural stalk rot incidence have been compared to yields in years when stalk rot is severe. iv. The characteristic symptoms is the blackening of the vascular bundles as black dots on the cut ends of the stalk. Stalks often rot at the first, internode above the soil level and become soft and brown. 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. Northern leaf blight (Heirninthosporium turcicum = Exserohilum turcicum) is a major problem in the region with cooler environment like J&K, H.P. Round to elongated uredo-pustules are on both the surfaces of the leaf. Brewbaker (2005) demonstrated that synthetic MIRSYN3 based on 19 highly resistant inbreeds showed resistance through 6 cycles of recurrent selection. 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). The most common pathways is infection via silk channel. Pre-Flowering Stalk Rot Disease 7. The characteristic reddening of the internal tissues are discernible when affected plants are longitudinally split open. The safety and integrity of the food supply are the paramount importance and are among the drivers of safe grain storage. ii. In order to diagnose diseases correctly, a diagnostic method based on hyperspectral imaging technology for Curvularia lunata and Aureobasidium zeae was proposed. iii. In paired plant technique, grain yields of adjacent diseased and healthy plants are compared. It is … Bacterial diseases. No alternate host for this disease has been found. ]: 9. ii. 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 … 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. 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. Stalk Rot Disease 6. | Plant Diseases, Diseases and Management of Grain Smut | Plant Diseases, Effects of M. Grisea on Plants | Plant Disease. The symptom appear at the lower node and may remain confined at one or two internodes only. Brown Spot Disease: This disease mainly occurs in sub-tropical and intermediate areas. 3 Nematodes, Parasitic. This results in death or bareness. The disease is favoured by high temperature i.e. 2 Fungal diseases. Of the 12 diseases recorded so far, Pythium stalk rot (P. aphanidermatum) and bacterial stalk rot (Erwinia chrysanthemi pv. If conditions are favourable and the disease is present in the host plant then it will start to develop and take over the plant. List of maize diseases. 10. Later, these chlorotic stripes turn brown and give a burnt appearance to the leaves. 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. They may coalesce and thereby produce scorching or drying of the leaves. 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. This disease has been considered as one of the major diseases of maize. 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. Subsequently adjacent planted fields can be severely damaged. For the first time was reported from Srilanka under the name ‘Sclerotial’ disease. Aspergillus Ear Rot Disease and Others. There are two fungal pathogens that cause GLS: Cercospora zeae-maydis and Cercospora zeina. Neil Groom, technical director for maize seed supplier Grainseed looks at … Because losses due to stalk rot may occur in several ways, yield loss estimates are difficult to obtain. 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. Name the types of nitrogenous bases present in the RNA. These two diseases are similar and difficult to distinguish. 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. Yield loss may result from premature plant death, thus stopping normal grain fill. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. 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. at the rate 0.25 per cent is a good safeguard against any possible seed-borne infection. Stripes may also be formed on sheaths, husks, and the stalks. Nematodes, Parasitic. MAIZE DISEASES I. Disease incidence varying from 2 to 80 per cent was observed affecting maize crop severely in Korea during previous two crop seasons. 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. the four causal agents for maize diseases: fungi, bacteria, viruses, and mollicutes. The galls are light coloured in the beginning and later on become dark. Fusarium Stalk Rot [Fusarium moniliforme Sheld. iii. Viral and fungal diseases are recorded as causing mortality of armyworms. Galls are first covered with a membrane that soon breaks open to expose a powdery mass and the vascular bundle of the host. 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. 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. Systemic fungicides usually act on but one site in the fungus, whereas protective (non-systemic) fungicides act on several sites. Disclaimer Copyright, Share Your Knowledge 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. 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. Ten downy mildew (DM) diseases are identified on maize. Fungicidal Management: Metalaxyl (Ridomil) can be applied to seed, in furrows as granules or sprayed on foliage. In true sense, it is decay of the internal pith tissues of the stalk. 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. When RH drop 50 per cent or below, no rot develop in the stalks. iii. Only young plants are susceptible. Symptoms seen on corn include leaf lesions, discoloration (), and foliar blight.. Seed treatment with captan or thiram at the rate 3 g/kg seed. Losses also occur with ear rot as a results of the ear on lodged plant coming in contact with soil. Green silks are relatively resistant. Post flowering stalk rot: Cephalosporium wilt (Black bundle disease and late wilt) Causal … The individual flowers may be infected on tassel and even through individual flower parts may be transformed into galls. Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. 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. ii. However, Zummo (1988) reported that heavy losses may occure due to this disease if infection occurs an early stages. Now it has become increasingly severe and assumed epidemic proportions in the next two decades. Dari . The cob formation either does not take place or the grain formation is partial or wholly affected. The yield losses depend on susceptibility of the host, spread of the disease and environmental conditions prevailing in the growing season. Post-Flowering Stalk Rot Disease 9. 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. Bacterial Stalk Rot:. Primary infection invariably occurs on lower proximate to the ground level. Sporangial production and infection require a film of moisture for 12-96 hours. Erwinia Stalk Rot (Erwinia chrysanthemi pv. Infections can also occur through wounds on stalks and leaves. The resulting diseases cause important losses in production both in crop and after harvest. Most diseases covered are economically significant or have the potential to become so. Development on lower surface is more as compared to upper surface. 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. etc., under conditions favourable for disease development, susceptible materials suffer heavy blightening resulting in premature drying of leaves and lightweight kernels. Do eukaryotic cells have restriction endonucleases? Sporangia and spore of the pathogen are disseminated by wind, rain and animals. Disease develops rapidly in warm weather and uredospores comprise both primary and secondary inoculum. 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 … Maize has several major disease issues; thus, breeding multiple disease resistant (MDR) varieties is critical. Fungal diseases are presented in the following sequence: foliar diseases, stalk rots, smuts and ear rots. Source of primary inoculum includes collateral cultivated and wild hosts, infected volunteer plants, kitchen gardens and certainly oospores, where formed. This disease usually affects maize grown in the tropics to moderate. Singh and Sharma (1976) estimated 40.5 per cent loss in grain yield with 71 per cent disease index. The disease is common during rainy season under hot and high soil moisture conditions. ii. Basic requirements Corn is best grown in warm, tropical and sub-tropical regions as it requires warm soils to develop optimally. Corn also requires ample space as it grows large in size a… 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. Use only disease resistant hybrids and composites in disease prone areas. What are the general characters of bryophytes? SINCE 1856 The disease caused drastic reduction in grain yield-to the tune of 97 per cent and exhibited a direct correlation with other yield parameters. 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. Potchefstroom Bacterial diseases of maize can cause headaches for producers. 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. At the Regional Agricultural Research Station, Rajouri and MBRSS, Poonch, it was moderate to high. 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). They could be shaken off or killed chemically. Sporangia are produced at low temperature (20-22°C), while oospores are formed at high temperature. The secondary infection take place by means of uredopustules which are wind born disseminated to the neighboring plants.
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