Biotic Stress Management in Tomato

Biotechnological Approaches

Shashank Shekhar Solankey, Md. Shamim

• Publisher: Apple Academic Press
• Year: 2021
• ISBN:
  9781000406696
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Science General
• Index: Biological Sciences

This valuable volume highlights biotechnological tools and their utilization for biotic stress management in the tomato plant, one of the world's most important vegetable crops consumed by us in our daily diet and which is vulnerable to over 200 diseases as well as the impact of global climate change.

The chapters cover the major diseases of tomato along with practical biotic stress management strategies through biotechnological and molecular approaches. The focus is on molecular tools that can be used to prevent or mitigate damage from such diseases as bacterial wilt, bacterial canker, damping off seedlings, late blight, early blight, fusarium wilt, septorial leaf spot, cercospora leaf spot, verticilium wilt, tomato leaf curl virus, tobacco mosaic virus, tomato spotted wilt virus, root knot nematode, fruit borer, and sucking pests. Gene stacking/pyramiding and postharvest management strategies are also systematically discussed.

This book provides an up-to-date and comprehensive review that will be a greatly useful resource, containing basic facts and information on the new and recent discoveries for biotic stresses management of tomatoes.

CHAPTER 1

TOMATO DISEASES, THEIR IMPACT, AND MANAGEMENT

S. S. SOLANKEY,¹ P. K. RAY,² MEENAKSHI KUMARI,³ H. K. SINGH,⁴ MD. SHAMIM,⁵ D. K. VERMA,⁶ and V. B. JHA⁷

¹Department of Horticulture (Vegetable and Floriculture), Dr. Kalam Agricultural College (Bihar Agricultural University, Sabour), Kishanganj, Bihar, 855107, India,
E-mail: [email protected] (S. S. Solankey)

²Krishi Vigyan Kendra, Saharsa (Bihar Agricultural University, Sabour), Bihar, India

³Department of Vegetable Science, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur - 208002, Uttar Pradesh, India

⁴Krishi Vigyan Kendra, Kishanganj (Bihar Agricultural University, Sabour), Bihar, India

⁵Department of Molecular Biology and Genetic Engineering, Dr. Kalam Agricultural College (Bihar Agricultural University, Sabour), Kishanganj, Bihar - 855107, India

⁶Department of Soil Science and Agricultural Chemistry, Dr. Kalam Agricultural College (Bihar Agricultural University, Sabour), Kishanganj, Bihar - 855107, India

⁷Department of Plant Breeding and Genetics, Dr. Kalam Agricultural College (Bihar Agricultural University, Sabour), Kishanganj, Bihar - 855107, India

ABSTRACT

Tomato is a well-known prime vegetable crop. It comes under a warm-season crop and is grown all over the world in warm and cool climatic conditions. The plant is extremely affected by adverse climatic conditions, i.e., responsible for promoting the disease infection. The warm and cool climatic conditions offer an optimal condition for the development of various foliar, stem, and soil-borne diseases in tomatoes. Diseases including fungal, viral, phytoplasma, and bacterial are the major limiting factors for its economic cultivation. The major diseases and its probable management in tomato are discussed here such as damping off, septoria leaf spot, early blight (EB), late blight, fusarium wilt, verticillium wilt, Cercospora leaf spot, anthracnose, powdery mildew, sclerotium collar rot, buckeye rot, bacterial wilt, bacterial canker, bacterial spot, tomato leaf curl virus (TLCV), tobacco mosaic virus (TMV), tomato spotted wilt virus (TSWV), tomato bunchy top virus (TBTV), and tomato big bud (TBB). For tomato growers, it would be better to incorporate integrated approaches for their management along with the use of resistant/tolerant high-yielding varieties; therefore, it could not economically affect the crop, as well as the recommended practices are feasible and easily understandable by the tomato growers.

1.1 INTRODUCTION

Tomato (Solanum lycopersicum L.) is one of the prime vegetable crops across the globe, shares a desirable position in India as a fresh vegetable, and also being used as a variety of processed products such as soup, juice, ketchup, sauce, puree, paste, canned fruits, and dehydrated tomatoes. It is susceptible to more than 200 diseases caused by pathogens, bacteria, viruses, and phytoplasma during its cultivation and postharvest management in existing varieties and hybrids (Abdel-Sayed, 2006; Singh et al., 2017). Outdoor production of tomato is seriously impaired due to increasing infections with evolving early blight (EB), late blight, and tomato leaf curl virus (TLCV) diseases (Scholthof et al., 2011), particularly in the Gangetic plains of India. Out of these bacterial wilts, bacterial canker, damping-off seedlings, fusarium wilt, septoria leaf spot, Cercospora leaf spot, verticillium wilt, tobacco mosaic virus (TMV) and tomato spotted wilt virus (TSWV) also causes the significant yield losses in tomato. Among all, TLCV is the most devastating disease in India. TLCV has become a major limiting factor in tomato cultivation, particularly during summer crop (February to May) in southern Indian states (Sadashiva et al., 2002) and autumn crop (August to December) in northern plains (Banerjee and Kalloo, 1987) and both early-autumn and autumn-winter (September to February) in Eastern India (Mandal et al., 2017). Disease management of tomatoes is essential for getting the optimal fruit yield. Not only the field-grown, even the crop grown under protected structures (poly houses, net houses, and polytunnels) and in kitchen gardens are also at high risk. For efficient management and to ensure timely control of diseases and its spreading, it is necessary to follow precautious measures along with early identification. The major tomato diseases, its diagnosis, impact, and its feasible control measures are as follows:

1.2 FUNGAL DISEASES OF TOMATO

1.2.1 DAMPING OFF (PYTHIUM, RHIZOCTONIA, PHYTOPHTHORA, ETC.)

It is a serious soil-borne pathogenic disease that chiefly affects seeds (pre-emergence) and new seedlings (post-emergence). Damping-off usually causes rotting of stems at the soil surface and root tissues below the soil surface. Sometimes, infected plants will germinate and look fine; however, within 2–4 days, they become water-soaked and squidgy, eventually fall over at the base and die. In the pre-emergence stage the seedlings are fall out just before they reach the soil surface or at seed emergence stage, while in the post-emergence stage the young, juvenile tissues of the collar at the ground level become softer and finally seedlings become fall off at collar region.

Hot water treatment of seeds (at 52°C for 30 minutes) is recommended as well as treats the seeds with fungicides like, Thiram/Captan/Metalaxyl-Mancozeb @ 2.5–3.0 g/kg of seeds. Drenching of nursery beds one week prior to sowing with Thiram/Captan or any copper-based fungicide @ 3 g/liter of water. Soil solarization of nursery area by cover the beds with transparent poly-sheets before sowing and left to open in direct sunlight for at least 10 days. Spraying the young seedlings with 0.2% Blitox or 0.25% Metalaxyl+Mancozeb, moreover 0.25% Fosetyl-Aluminum is found most effective against this pathogen. Provision of proper drainage to the beds, avoid dense planting, removal of infected seedlings from beds, and avoid flooding the beds as soon as the symptom arises to check spread of the disease.

1.2.2 SEPTORIA LEAF SPOT (SLS) (SEPTORIA LYCOPERSICI)

The characteristic symptom is small, water-soaked circular spots of 1.6 to 3.2 mm in diameter first appeared on the lower surface of older leaves. The circular spots have a dark brown margin with gray or tan heart. When spots reached to maturity, they enlarge to a diameter of about 6–7 mm and coalesce.

The center of the spots will show various dark brown, pimples-like structures that are known as pycnidia fruiting bodies of the pathogen. The structures can be seen with the necked eyes or by hand lens because they are large enough. At lateral stage, these spots may also appear on stems, calyxes, and blossoms, but rarely on fruits. Severely infected leaves will turn yellow, then dry up and finally drop off. This drop off of leaves will result in exposure of fruits in direct sunlight and cause physiological disorder, sun-scald.

Use disease-free seed or if the seed is suspected, then treat with hot water at 50°C for 25 minutes. Apply crop rotation with non-related crops for at least 3 years. Uprooting infected plants at the end of the growing season to prevent the spores from overwintering in the field. Plucked off and destroy infected leaves at first occurrence of the symptom and disinfect pruning tools before moving from one plant to another. Apply copper-based fungicides, e.g., copper oxychloride or bio-agent Bacillus subtilis for effective management of this disease, especially when used as a prophylactic measure for its management.

1.2.3 EARLY BLIGHT (EB) (ALTERNARIA SOLANI)

This is also a common disease of tomato, initially occurring on the leaves or foliage at any stage of the plant growth. The characteristic symptom is the appearance of small, black lesions predominantly on the older leaves. Day-by-day spots enlarge, and with time the diseased area expanded up to 0.25 inch in diameter or larger, concentric rings in a bull’s eye pattern can be seen at the center. At the lower surface of the leaves just behind the bulls-eye-shaped brown spots, often the tissue around the spots will turn yellow. The fungus primarily attacks on the leaves/foliage, causing characteristic leaf spots and blight. Further, infected leaves will drop from the plant. In many cases, the tomato fruits will continue to ripe, as well as the disease symptoms will also appeared on the skin of the fruit. Under favorable conditions (hot and humid), much of the foliage will die. Lesions on the shoots are similar to those on leaves, occasionally girdling the plant, if they occur near the soil surface. In fruits, the infection transmitted by calyx or stem attachment. Lesions attain substantial size, usually on the entire fruit; concentric pitted spots are also seen on the surface of the fruit. Apart from the foliage symptoms that are known as EB, this disease generally causes less economically significant symptoms on tomato crop, including collar rot, stem lesions on the fully developed plant and fruit rot (Walker, 1952). Due to EB disease the yield losses up to 79% have been reported from India, Canada, United States, and Nigeria (Datar and Mayee, 1981).

The pathogen of EB lives in the soil and once a field has shown symptom of the EB pathogen, it will remain persist in the soil, because the fungus easily overwinters in the soil, even in cold months. Luckily, most tomatoes will continue to produce fruits even with moderately severe infestation of EB. Growing of resistant varieties like Arka Rakshak, Arka Samrat, Arka Vikas and Swarn Sampada are the best practice to prevent the tomato crop from this fungal disease, moreover mulching with a layer of paddy straw, leaf mold, or well-decomposed compost immediately after they are transplanted. Actually, this mulch creates a protective barrier that prevents the soil-borne spores from splashing up out of the soil and onto the plant. When the pathogen strikes, organic fungicides like Bacillus subtilis or copper-based fungicides can help to prevent or control the spread of this pathogen. Bicarbonate fungicides are also found effective (including Bi-carb, Green cure, etc.), against this disease. As prophylactic measure, spray the crop with 0.3% Diathane M-45 or 0.1% Carbendazim or 0.2% Chlorothalonil at 10–15 days intervals starting from 45 days after transplanting. Two sprays of 0.2% Chlorothalonil or Difenoconazole (0.5 g/lt) is also effective to control this disease.

1.2.4 LATE BLIGHT (PHYTOPHTHORA INFESTANS)

In the past one decade, the late blight is observed as the most destructive tomato disease. This plant pathogen is one of the most distressing organisms in human history, being responsible for the shocking Irish potato famine in the 1840s, and it is arguably the most important pathogen of tomatoes, causing yield loss of 91.80% (Byrne et al., 1997). The fungal spores create irregular-shaped, slimy, and water-soaked blotches on foliage. Often the blotches occur initially on the top leaves and stems. Later on, infection occurs on entire stems and it will “rot,” turning black in color and slimy. Sometimes white spores’ patches may also be appeared on the leaf undersides. In the northern plains of India, the pathogen overwinters in buried potato tubers after harvesting. However, in the southern parts of India, it easily survives during winter. Late blight disease commonly occurs in humid regions with cool temperatures ranging from 15–21°C and cloudy weather; however, prolonged hot dry days can check its spread. Under ideal condition, the disease development is rapid, causing serious economic losses. Lesions on the leaves initially produce irregular large shaped, greenish-black, and water-soaked spots. These spots enlarge rapidly, becoming brown, and under humid conditions, develop a white moldy growth close to the margins of the diseased area on the lower surface of the leaves and on stems also. The disease spread speedily under humid conditions and destroying quickly large areas of leaf as well as shoot tissues. Fruit lesions come with large, green to dark brown, principally on the upper half of the fruit, but they may also find on other parts. Under humid conditions, white moldy growth may also appear on fruits surface and thereafter converted into black color. The disease damaged the fruits as well as the foliage of the plant. Characteristic symptoms on the fruits generally begin on the shoulders of the fruit because spores land on fruits from the upper parts of the plant. However, it is a worldwide problem, but most severe epidemics occur in frequent cool and moist areas. In Bihar, the highest disease infestation and severity occurred during the month of January-February when the maximum temperature ranged from 10.4–10.8°C and maximum relative humidity ranged from 90–95% (Solankey et al., 2017).

The spores of this disease are easily transmitted by winds for miles that promote its fast infection. Late blight is an uncommon fungus, but once it occurs, there is a very limited option to prevent its infection because the spores spread so hastily. If it struck on few plants then uproot and destroy them immediately to check spores spreading. Few bio-agents like, Bacillus subtilis is effective to some extent in preventing this disease when it’s first knocked in your area. Under prevailing weather condition, prophylactic spray ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Contributors
• Abbreviations
• Preface
• 1. Tomato Diseases, Their Impact, and Management
• 2. Molecular Tools for Bacterial Wilt Resistance in Tomato
• 3. Molecular Methods for the Controlling of Damping Off Seedlings in Tomato
• 4. Molecular Methods for the Controlling of Late Blight in Tomato
• 5. Molecular Approaches of Early Blight Resistance Breeding
• 6. Molecular Approaches for the Control of Septoria Leaf Spot in Tomato
• 7. Molecular Approaches for the Control of Cercospora Leaf Spot in Tomato
• 8. Molecular Approaches for the Control Tomato Leaf Curl Virus (TLCV)
• 9. Molecular Advances of the Tobacco Mosaic Virus Infecting Tomato
• 10. Molecular Approaches to Control the Root-Knot Nematode in Tomato
• 11. Molecular Approaches for the Control of Fruit Borer in Tomato
• 12. Molecular Approaches for Control of Sucking Pest in Tomato
• 13. Molecular Approaches for Multiple Genes Stacking/Pyramiding in Tomato for Major Biotic Stress Management
• 14. Molecular Approaches for the Postharvest Losses in Tomato by Different Biotic Stresses
• Index