Diseases of Field Crops Diagnosis and Management

Volume 1: Cereals, Small Millets, and Fiber Crops

J. N. Srivastava, A. K. Singh, J. N. Srivastava, A. K. Singh

• Editore: Apple Academic Press
• Anno: 2020
• ISBN:
  9781000439106
• Edizione: 1
• Argomento: Ciencias biológicas
• Categoria: Botánica

Plant diseases cause yield loss in crop production, poor quality of produce, and great economic losses as well. Knowledge of the perpetuation and spread of the pathogens and various factors affecting disease development is an important need. Disease diagnosis is the prime requirement for determining preventive or curative measures for effective disease management. This new 2-volume set, Diseases of Field Crops, helps to fill the need for research on plant diseases, their effects, how they spread, and effective management measures to mitigate their harmful consequences.

The volumes in this set showcase recent advances in molecular plant pathology and discuss appropriate diagnostic techniques for identification of causal agents and diseases, providing the information necessary to establish management strategies. The chapters in these two volumes include detailed description of symptoms, causal organisms, disease cycles, epidemiology, and management techniques of economically important diseases. The volumes explore existing strategies and offer new methods that can be used in an integrated manner and with a comprehensive approach for the management of major diseases of the field crops. Also taken into consideration is the impact of global climate change on the spread and severity of plant diseases.

This volume focuses on a selection of cereal crops or grains for fodder and human food and the diseases that affect them. The crops include rice, maize, wheat, millet, sorghum, jute, and more. Volume 2 covers pulses, oil seeds, narcotics, and sugar crops.

CHAPTER 1

Present Scenario of Diseases in Rice (Oryza sativa L.) and Their Management

S. Krishnam Raju¹, V. Bhuvaneswari², J. Krishna Prasadji ¹, P.V. Satyanarayana³

1 Department of Plant Pathology, Andhra Pradesh Rice Research Station and Regional Agricultural Research Station, Maruteru–534122, West Godavari District, Andhra Pradesh, India, E-mail: [email protected]

2 Department of Plant Pathology, Andhra Pradesh Rice Research Station and Regional Agricultural Research Station, Maruteru–534122, West Godavari District, Andhra Pradesh, India

3 Andhra Pradesh Rice Research Institute and Regional Agricultural Research Station, Maruteru–534122, West Godavari District, Andhra Pradesh ANGRAU, Andhra Pradesh, India

1.1 INTRODUCTION

Rice (Oryza sativa L.) is a consequential staple victuals crop for a more sizably voluminous part of the world’s population and is engendered around the globe. More than 3 billion people, half of humanity, eat rice as their staple food. Globally rice is cultivated on approximately 158.8 M ha on 11% of the world’s cultivated land and 685 million tonnes produced annually (FAO, 2009). More than 90% of the rice production of the world is grown in Asia. World production of rice has been steadily rose from 200 MT of raw rice in 1960 to over 472.09 MT in 2015. China was the leading rice producer followed by India, Indonesia, and Bangladesh in 2015–16. India is the 2^nd largest producer of rice in the world with an area of 43.46 M ha. India’s rice production was at around 103.5 MT during 2015–16 and it was projected to 104.82 MT during August 2016 (USDA, Foreign Agricultural Service (FAS) (m.world-grain.com)). It is grown in almost all the states of India contributing about 42% of the country’s foodgrain production and provides the livelihood for about 70% of the population. India was the largest exporter of rice in 2015–16 followed by Thailand, Vietnam, and Pakistan. The world needs 8–10 MT more rice each year to meet people’s needs and keep rice affordable. The population of rice eaters is increasing at an exceptionally fast rate and the number of rice consumers will probably double by 2020. The country needs to increase its rice production at a rate of 3.75 MT per year until 2050 to meet its food security. The requirement of rice by 2025 is estimated to be around 125–127 MT.

The demand for food and processed commodities is increasing due to growing population and rising per capita income. There are projections that demand for food grains would increase from 192 million tonnes in 2000 to 345 million tonnes in 2030. Hence, in the next 20 years production of food grains needs to be increased at the rate of 5.5 million tonnes annually.

Although, India is having the maximum area under rice cultivation but several biotic and abiotic factors are mainly responsible for low production and productivity of rice. Due to apparent changes in climatic conditions, change of genotypes and cultivation practices, the profile of diseases in rice has changed over a period of time. Several pathogenic diseases have been found to occur on the rice crop resulting in extensive damage to grain and straw yield. Among diseases blast, sheath blight, bacterial leaf blight (BLB), sheath rot, brown spot, stem rot, false smut, and rice tungro cause severe yield losses in rice.

1.2 BLAST DISEASE

1.2.1 ECONOMIC IMPORTANCE

It is also known as rice blast disease, rice rotten neck, rice seedling blight, blast of rice, oval leaf spot of graminea, pitting disease, ryegrass blast, Johnson spot. Blast is considered a major disease of rice because of its wide distribution and destructiveness under favorable conditions. Blast occurs over 85 rice growing countries of the world causing considerable reduction in yield. The disease was first recorded as ‘rice fever disease’ in China by Soong Ying-shin in 1637. In Japan, it is believed to have occurred in Imochi-byo as early as in 1704. In Italy, the disease called ‘brusone’ was reported in 1828 and in U.S.A in 1876. The causal organism was first detected by Cavara in 1891 from Italy.

In temperate and subtropical Asia, blast is highly destructive in lowland rice and in tropical Asia, Latin America, and Africa, it affects upland rice.

In India, the occurrence of this disease was first reported from the Tanjore district of Tamil Nadu in 1918, Maharashtra in 1923 and subsequently in several other parts. Since then heavy destruction of rice crop due to this disease over large areas have been reported from Andhra Pradesh, Kerala, Maharashtra, Gujarat, Orissa, West Bengal and other states of the country. Now it occurs in almost all principal rice-growing states of the country. In severe cases, losses amounting to 70–80% of grain yield are reported (Ou and Nuque, 1985).

In India blast epidemics were reported from the Sub-Himalayan regions of Jammu and Kashmir, Andhra Pradesh, Tamil Nadu and Coorg regions of Karnataka and North Eastern region comprising the states of Arunachal Pradesh, Manipur, Mizoram, Meghalaya, Assam, and uplands of Bihar and Orissa.

Although blast is capable of causing very severe losses of up to 100%, little information exists on the extent and intensity of actual losses in farmers’ fields. Losses of 5 to 10%, 8%, and 14% were recorded in India (1960–1961), Korea (mid-1970s), and in China (1980–1981), respectively. In the Philippines, yield losses ranging from 50 to 85% were reported.

1.2.2 SYMPTOMS

The fungus attacks all aerial parts of plants at all stages of growth and they can symptoms produce on plant parts such as leaf (leaf blast), leaf collar (collar blast), culm, culm nodes, panicle neck node (neck rot), and panicle (panicle blast).

1.2.2.1 LEAF BLAST

Symptoms on the leaves originate as small specks which subsequently enlarge into spindle-shaped spots varying in length from 0.5 cm to several cms. The center of a well-developed spot is whitish-grey with a brown margin. Under favorable conditions, lesions on the leaves expand rapidly and tend to coalesce, leading to complete necrosis of infected leaves giving a burnt appearance from a distance. So the name rice blast is given to this disease. Similar spots are also formed on the sheath.

1.2.2.2 COLLAR BLAST

Collar blast occurs when the pathogen infects the collar that can ultimately kill the entire leaf blade.

1.2.2.3 NODE BLAST

The pathogen infects the culm node that turns grayish brown to blackish and breaks easily at the point of infection. This condition is referred as node blast.

1.2.2.4 NECK BLAST

The neck of the panicle is infected when the earhead em...