There should be dew for at least four hours during the night. The Tamil Nadu Agricultural University, Coimbatore, is playing a pivotal role in design ... capsule for the management of pests and diseases besides post-harvest management practices. 6. (b) Relative humidity should be more than 70 per cent. Maximum temperature is positively correlated with the population in 20- 30 day old crop and with the disease incidence in 45 day old crop. Generally these diseases can damage the crop by 10 – 15 per cent. Though the black rust can survive in the northern hills throughout the summer season, the source of inoculum concerned in the epidemiology of the black rust is the Nilgiri hills of the south. Rodent pests B. Pests of Regional Significance 1. Bright yellow pustules (Uredia) appear on leaves at early stage of crop and pustules are arranged in linear rows as stripes. iii. iii. If these conditions prevail for two days, late blight of potato is likely to appear after a period of 10 days. Affected plants can be pulled out easily. The weather conditions favourable for the incidence of late blight are given below: i. Author: TNAU. Late blight of potato could be predicted by using synoptic charts and warnings were issued four days ahead for spraying the potato crop against late blight. B. Prevost showed bunt of wheat is a fungus and showed evidence that a disease is caused by a microorganism. Temperature should persist between 10-24°C for at least two days. Later on during winter season, when wheat crop is grown in the plains of north India, rust has the tendency to migrate from the Nepal hills to plains of north India. ii. Survival : Both survive on stubbles and volunteer crops, Pustules (containing masses of urediospores) are dark reddish brown - occur on both sides of the leaves, on the stems, and on the spikes. Powdery mildew: Erysiphe graminis var. Different rules have been suggested for the forecast of late blight of potato: According to this rule, following weather conditions must prevail: i. Under these conditions, late blight of potato is expected to appear after about a week. The leaf tissue turns yellow and chlorosis reach towards the centre of the leaf and form V shaped area with base of V towards the midrib. Dark coloured streaks are formed on the stem from the ground level and gradually these streaks enlarge and girdle the stem. iii. It has been studied by many workers that weather conditions are favourable for the survival of the wheat rust on the mountains of Himalayas. Wheat rust can be divided into three types: Yellow rust is mainly confined to the northern parts of India due to its low temperature requirement. Higher duration of leaf wetness due to dew, fog and rainfall. Lecture 18 - Diseases of Mulberry Mulberry Root rot- Macrophomina phaseolina Symptoms Sudden wilting, withering of leaves and affected plants fail to sprout after pruning and dry up completely. Sunshine hours should range between 3.3 – 7.8 hours per day. ii. If these conditions continue for several days, then disease is likely to appear. The basis for the forecasts was a thorough study of the over and early spring renewal of the rust as related to late winter and early spring weather conditions. ii. Brown rust can appear in the entire wheat belt under favourable weather conditions. These diseases are found all over the world, where the groundnut is cultivated. There should be excessive rainfall during the reproductive period. Multiple regression indicated that maximum temperature alone is important in predicting the disease outbreak. Wheat provides nourishment to 35% of world population. Ergot symptoms become evident during kernel formation, when ergot bodies are formed in place of kernels. Based on the above weather conditions, the forecasting of the disease can be made. Infections from spores arriving from a distance are termed primary infections. When these weather parameters become favourable, late blight of potato appears. AESA BASED IPM - WHEAT Directorate of Plant Protection Quarantine and Storage N. H. IV, Faridabad, Haryana National Institute of Plant Health Management Rajendranagar, Hyderabad, Telangana ... Diseases 3. It moves from southern India towards Punjab. Favourable weather conditions for its multiplication are given below: (a) Mean air temperature should range between 16 to 27°C. Weather conditions favourable for the appearance of yellow rust are given below: (a) Mean air temperature should range between 9 to 13°C. Till … ii. ii. Image Guidelines 5. … Early leaf spot and late leaf spot. Therefore, incidence of late blight of potato is common in hilly regions. These black teliospores often are blown away by the wind, leaving only the bare rachis and remnants of other floral structures. i. After reading this article you will learn about:- 1. Aeciospores germinate at 17-22°C and infect other plants forming either secondary Aecia or Uredia depending upon prevalent temperature of 25°C. Cloudy weather and dark period during night is more congenial for the speedy development of the disease. Calm to light wind, intermittent rainfall, rainy days followed by clear days with bright sunshine and again rainy days with high humidity are favourable for the rapid spread of the disease. Greyish white powdery growth appears on the leaf, sheath, stem and floral parts. Threshold of 10,000 juveniles/kg soil develop disease. • Infections occur during periods of extended wetness. Loose Smut - Ustilago tritici, Stem Rust / Black Rust: Puccinia graminis f.sp. tritici, Stripe Rust /Yellow Rust-Puccinia striiformis, Home | About Us | Success Stories | Farmers Association | TNAU Publications | Contact Us, The postules are circular or slightly elliptical, smaller than those of stem rust, usually do not coalesce, and contain masses of orange to orange-brown Urediospores.Â. About 90 per cent relative humidity persist for at least 10 hours. Minimum temperature should not be less than 10°C. iii. Nene YL, Saxena SC, Singh A, Mishra AB, Singh DV, Joshi LM, Tyagi PD, Ruikar SK, Gupta RS, 1971. Mean temperature should be between 22.5-23.5°C. (c) There must exist partly cloudy conditions. Dew, fog and rainfall are important sources of moisture, which keep the leaves wet. There should be intermittent rainfall. Wide spread infection is directly associated with wet weather. Humid conditions caused by excessive rainfall should persist. ii. Favourable weather conditions for the appearance of leaf spots are given below: i. Disease symptoms. TNAU assumed full responsibilities of Agricultural Education and Research and supported the State Agricultural Department by delivering research products. ii. It is intended primarily for agricultural researchers, technicians and farmers in developing nations, but will also be of value to others. ii. The stripes are yellow to orange yellow. These biotic agents are, therefore, infectious, and the diseases they cause are termed infectious diseases. Diseases of Wheat 2. However, the following weather conditions should persist: i. Diurnal range of temperature should range between 24-34°C. This rust appears in Punjab usually by the end of February to mid-March. Temperature should range between 19-37°C during summer season and 17-26°C during winter season. Therefore, forecast of this disease is very easy. Yield loses up to 70% have been reported, ranging from 30-70% . I take this opportunity to thank the Agricultural Production Commissioner & Principal ... 3 WHEAT 122 4 PULSES 125 i. Redgram 125 ii. Based on these parameters, humid thermal ratio (HTR) was developed for use in the disease prediction model. Disease cycle of loose smut of barley is similar to as of loose smut of wheat. In India, during summer season, high temperatures do not allow either the wheat crop or the rust to survive in the plain areas. This rule lays down the following criteria for the forecast of late blight of potato: i. If transplanted crop: Before the spore masses break through the epidermis, the infection sites feel rough to the touch, As the spore masses break through, the surface tissues take on a ragged and torn appearance. Higher the duration of wetness, higher is the infection. The culture exhibited resistance to black (stem), yellow and brown (leaf) rusts. During this period generally the weather conditions become favourable for the spread of black rust in Punjab. Mean relative humidity should be around 87 per cent. It is an important disease of groundnut. ii. The northern states of Punjab and Haryana Plains in India have been prolific wheat producers. The Tamil Nadu Agricultural University (TNAU) had its genesis from establishment of an Agricultural School at Saidapet, Madras, Tamil Nadu, as early as 1868 and it was later relocated at Coimbatore. caused by rice disease in a year were to be only 5% of the total rice production in the country, it would amount to a great deal, and prevention of such a loss should constitute one of the important methods of augmenting our food security. Pustules also can be found on leaf sheaths, necks, and glumes. ii. Wide fluctuations in maximum temperature from 24-39°C, ii. Rotting of primary and secondary roots, rotten roots turn black and roots contain large number of black sclerotia. Disease symptoms Symptoms are produced on almost all aerial parts of the wheat plant but are most common on stem, leaf sheaths and upper and lower leaf surfaces. Diseases of Rice: i. Agro-ecosystem analysis (AESA) based integrated pests management (IPM) A. AESA B. One of the factors causing plant diseases is parasites, those living organisms that can colonize the tissues of their host-plant victims and can be transmitted from plant to plant. Relative humidity at 1500 hours should not be less than 75 per cent. Wheat is the staple food for over ten billion people in as many as 43 countries of the world. The pathogen survives from one season to the next as dormant mycelium (fungal threads) within the embryo of the barley seed. Crop: Wheat, Scientific Name: Triticum aestivum Family: Poaceae : Leaf Rust/Brown Rust : Stem Rust : Stripe Rust/Yellow Rust : Loose Smut : Powdery Mildew Weekly cumulative rainfall should exceed critical value for two weeks. There should be intermittent cloudiness and dew. Generally cloudy weather, low temperature and high humidity are favourable for the development of the disease. The pustules of stripe rust, which, contain yellow to orange-yellow urediospores, usually form narrow stripes on the leaves. Book Detail: Language: English Pages: 133 Author: TNAU Price: Free How to Download Book (Full guide) BREEDING OF FIELD & HORTICULTURAL CROPS – Course Outline RICE – Oryza sativa Rice Varieties Released Using Different Breeding Techniques Hybrid Rice Seed Production WHEAT – Triticum sp. Several studies have been conducted to predict late blight of potato by using various environmental conditions. Prohibited Content 3. 5. Similarly, Nilgiri hills in south India are the source region of wheat rust, where wheat is cultivated throughout the year. Source of Microscopic images: Diseases of small grain cereal crops- A colour handbook by TD Murray, DW Parry and ND Cattlin The weather conditions favourable for the incidence of disease are given below: i. 1755 - French botanist Tillet published a paper on bunt or stinking smut of wheat; discovered bunt is a disease of wheat. Yellow or stripe rust - Puccinia striiformis Symptom Mainly occur on leaves than the leaf sheaths and stem. In fact, Himalayas are the source regions of wheat rust in the north and Nilgiri hills in the south. Night temperature should be greater than 10°C. Diseases of Potatoes. The weather conditions favourable for the incidence of late blight of potato are given below: i. Stem ust / Black rust - Puccinia graminis f.sp.tritici, Stripe rust / Yellow Rust - Puccinia striiformis from infected wheat heads. Infection sites primarily are found on the upper surfaces of leaves and leaf sheaths and occasionally on the neck and awns. A system for forecasting the severity of wheat leaf rust in USA has been distinctly successful. During winter season, western disturbances cause cloudiness, rains, dew and fog over North India. Lecture 03 - Wheat: Lecture 04 - Pearl Millet: Lecture 05 - Maize: Lecture 06 - Sugarcane: Lecture 07 - Turmeric: Lecture 08 - Tobacco: Lecture 09 - Groundnut: Lecture 10 - Castor: Lecture 11 - Sunflower: Lecture 12 - Sesamum: Lecture 13 - Cotton: Lecture 14 - Red gram: Lecture 15 - Black gram: Lecture 16 - Green Gram: Lecture 17 - Bengal Gram: Lecture 18 - Soyabean: DISEASE OF FIELD CROP AND … Leaf spot may be of two types. 4. If north to north-westerly winds persist, then the rust is likely to assume the highest severity. Copyright 10. Early leaf spot can appear after a few weeks of sowing. Leaf Rust / Brown Rust - Puccinia recondita Stem become hollow due to internal rotting. However, intermittent rains are more favourable for the disease development than continuous dry spells or rainy days. 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