Post flowering stalk rot: Cephalosporium wilt (Black bundle disease and late wilt) Causal … Maize aphid: Attacks are on leaves as a black fungal growth (called sooty mold) often occurs on the honeydew secreted by aphids. The Peronoslerospora spp are seed borne in nature. In present scenario, the trade among the developing countries is expanding; hence quality of the produce is becoming a major concern. Erwinia Stalk Rot (Erwinia chrysanthemi pv. 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. There seems to be no controversy about soil borne of the disease. When formed on the cob they cause extensive damage. The presence of downy whitish to creamy growth usually on the ventral surface of the infected leaves corresponding to- stripes is the most characteristic symptom. This may cause the stalk to appear gray-black. Greatest loss results from systemic infection. The inner tissues also get infected in severe cases. Internal mycelium is inactivated by drying seed to 20 per cent or less moisture and storing for about 3 weeks. In some cases the red streak may also be observed. Share Your PDF File If only the parts of the tassels and ears are converted into galls, the floral bracts turn into leafy structures. In the adult plants the symptoms are not visible till maturity. The secondary infection take place by means of uredopustules which are wind born disseminated to the neighboring plants. Three sprays of Dithane M-45 beginning from first appearance of symptoms at 15 days interval can minimize the disease. A fungicide application is useful when pustules first appear on the leaves. The characteristic symptoms is the blackening of the vascular bundles as black dots on the cut ends of the stalk. 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. The symptoms manifest on leaves, sheaths, stalk and ear. A mild sweet... 2. RFLP markers flanking this locus have been identified. Systemic fungicides usually act on but one site in the fungus, whereas protective (non-systemic) fungicides act on several sites. This disease is air born. Infected plants do not... 3. zeae Victoria, Arboleda and Munoj): It is one of the most important disease of maize in tropical countries. The specks elongated to form fine discontinuous stripes. 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. when it is not more than 30 days old (knee-high stage). Symptoms start with lesions usually noticed on the bottom leaves first, which then spread to upper leaves when spores are released. Although, the disease may be externally seed-borne, the major source of infection is soil-borne inoculums. 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. These studies clearly indicate that a few major loci undergrid general resistance to polysora rust in tropical maize germplasm. These changes in technology are bringing along an increase in problems, specially insects and diseases, that were not previously considered problems of any significance. The damage is most common at or near the tip of the ear; silk infection is favoured by high night and day temperature. 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. Bacterial Stalk Rot:. Development on lower surface is more as compared to upper surface. The cob formation either does not take place or the grain formation is partial or wholly affected. For the first time was reported from Srilanka under the name ‘Sclerotial’ disease. 4 Virus and virus-like diseases. Black Bundle Disease (Cephalosporium acremonium Corda): Banded Leaf and Sheath Blight (BLSB) Disease, The best answers are voted up and rise to the top. Use resistant varieties. Stalk rots are the most serious and widespread group of the diseases in maize. at the time of silking. 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. avenae Manns (syns. Why does plant cell possess large sized vacuole? The stripes extend in parallel fashion, have well defined margins and are delimited by veins. 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. Plants are weak and those with rotted stalks always have rotted roots. The severity of the disease is influenced by temperature and moisture. Sow the resistant varieties like GS-2 and Ganga-101 which are comparatively resistant. Share Your PPT File. The galls are light coloured in the beginning and later on become dark. The individual flowers may be infected on tassel and even through individual flower parts may be transformed into galls. SINCE 1856 Later on these pustules turn black due to formation of teleutospores. ii. Demand for maize in both national and international market is high. 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. Maize Field Guide Maize Crop Development, Pests and Diseases. iv. 2 and SSR markers closely linked to this locus. Of the many foliar blight diseases occurring in India, three may be considered important based on geographical distribution and yield loss potential. Welcome to BiologyDiscussion! 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. Stem galls result in loss in yield and bending of the stalk. Post-Flowering Stalk Rot Disease 9. Charcoal Rot Disease 10. A definite relationship of disease development with rainfall pattern in different region ns has been mapped. A major gene on chr. Virus and virus-like diseases. Stalk rot, ear rot, kernel rot can occur in infected tissue although many times infected tissue have no symptoms. 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. Because losses due to stalk rot may occur in several ways, yield loss estimates are difficult to obtain. 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. 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. It is known to be present in severe intensity in the states of Himachal Pradesh, Uttar Pradesh, Uttaranchal, Haryana. Ashby]. It appears with the formation of tassels and ears where partial or complete transformation of the inflorescence into sori may be observed. 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. In young seedlings the plants dry up in the early stage of the growth. A major QTL located on the short arm of chromosome 10, explained 83% of the phenotypic variation, with the NC300 allele carrying the resistance. What are the three important components of biodiversity? 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. Disease cycle The primary source of infection is through oospores in soil and also dormant mycelium present in the infected maize seeds. 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. Ultimately the entire plant dries up. Control a Spray with insecticides like vetox 85, and practice crop rotation. Typically, the first sign of stalk rot is plant wilting. Subsequently adjacent planted fields can be severely damaged. Find the perfect maize disease stock photo. 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. Avoid water stress after flowering of the plant. Ears frequently abort and are replaced by leafy buds. This disease has been considered as one of the major diseases of maize. 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. Pythium Stalk Rot Disease 8. Aspergillus Ear Rot Disease and Others. 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. Yellow peach moth is a minor and irregular pest of maize in Queensland. Infection usually begins with a few plants in early sown fields. The growth of the fungus can be seen on both the surfaces of the stripes. Curvularia lunata and Aureobasidium zeae are the main leaf diseases of maize in Northeast China. 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. The primary source of inoculums are sclerotia in the soil and grass hosts that grow in the vicinity of maize crop. Fungicidal Management: Metalaxyl (Ridomil) can be applied to seed, in furrows as granules or sprayed on foliage. 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 … Basic requirements Corn is best grown in warm, tropical and sub-tropical regions as it requires warm soils to develop optimally. 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. 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. 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. Diseases in maize require certain environmental conditions to develop. Source of primary inoculum includes collateral cultivated and wild hosts, infected volunteer plants, kitchen gardens and certainly oospores, where formed. Sporangia and spore of the pathogen are disseminated by wind, rain and animals. 66 per cent was recorded in intermediate zone of Jammu region. Infections can also occur through wounds on stalks and leaves. 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. 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. Disease incidence varying from 2 to 80 per cent was observed affecting maize crop severely in Korea during previous two crop seasons. In severe cases, leaves dry and plants may wilt. These two diseases are similar and difficult to distinguish. However, it became increasingly severe and assumed epidemic proportions in the next two decades. i. 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. Sun drying of seeds lead to inactivation of mycelium present in seed and also reduce moisture levels. The disease symptoms appear only near maturity. Symptoms seen on corn include leaf lesions, discoloration (), and foliar blight.. 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. 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. Proceedings of the International Maize Virus Disease Colloquium and Workshop, August 2-6, 1982. This results in death or bareness. Resistant lines normally show small chlorotic or necrotic flecks with no sporulation. Grow resistant/moderately resistant var. Payak and Sharma (1985) have reported that annually at least 1% of the total grain yield is reduced by BLSB in India. The pathogen over winters as sclerotia and may penetrate roots and lower stems during growing seaspn. Dari . It is externally seed borne and soil borne. The safety and integrity of the food supply are the paramount importance and are among the drivers of safe grain storage. The natural disease pressure every winter cycle allowed for the selection of disease resistant germplasm. 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. However, Zummo (1988) reported that heavy losses may occure due to this disease if infection occurs an early stages. As the leaves are infected by the pathogen, it drastically reduces the total photosynthetic area of the diseased plants, causing reduction in grain yield. Maize mosaic virus and other maize virus diseases in the islands of the Western Indian Ocean. Losses also occur with ear rot as a results of the ear on lodged plant coming in contact with soil. A tan sooty black, greenish or greenish yellow mold grows on and between kernels. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. The basal internodes develop soft rot and give a water soaked appearance. The spore retain viability for two years. In paired plant technique, grain yields of adjacent diseased and healthy plants are compared. This can lead to reduced growth. Disease develops rapidly in warm weather and uredospores comprise both primary and secondary inoculum. Stalk rot is first recognized when the plants first lodge but do not break over. The infected tissues are at first soft but later on they turn into dry mass of shredded fibers. The mycelium develops above and between kernel rows. This disease mainly occurs in sub-tropical and intermediate areas. Neil Groom, technical director for maize seed supplier Grainseed looks at … Distinct symptoms of GLS are … Galls are first covered with a membrane that soon breaks open to expose a powdery mass and the vascular bundle of the host. They also stated that the maturity and Polysora rust rating were slightly correlated, but QTL for the two traits did not co-localize. Larvae tunnel into stems or cobs producing masses of webbing and excreta at the tunnel entrance. No need to register, buy now! This disease has been reported in Kliarif season in areas having temperature ranging 30-35°C and RH (relative humidity) 80-100 per cent. It is caused by incited by Thanatephorus sasakii (Shirai) Tu & Kimbro; anamorph Rhizoctonia solani f.sp. at the rate 0.25 per cent is a good safeguard against any possible seed-borne infection. In true sense, it is decay of the internal pith tissues of the stalk. 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. In initial stage, leaves become gray, ears drop and outer rind of lower stalk may turn brown. Jines (2006) prepared a multiple interval mapping model, including four QTL, accounted for 88% of the variation among average disease ratings. Oospores remain viable for at least three years and this viable oospores material constitutes the main source of inoculums. Share Your Word File ii. This disease usually affects maize grown in the tropics to moderate. 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. (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. i. These types of studies are confounded by year-to-year in average yield. What are the general characters of bryophytes?