Rust disease in plants lin

Plant Rust disease, disease cycle, its types, prevention.
INTRODUCTION
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales (previously known as Uredinales).
An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus Puccinia, are currently accepted.[1] Rust fungi are highly specialized plant pathogens with several unique features. Taken as a group, rust fungi are diverse and affect many kinds of plants. However, each species has a very narrow range of hosts and cannot be transmitted to non-host plants. In addition, most rust fungi cannot be grown easily in pure culture.
A single species of rust fungi may be able to infect two different plant hosts in different stages of its life cycle, and may produce up to five morphologically and cytologically distinct spore-producing structures viz., spermogonia, aecia, uredinia, telia, and basidia in successive stages of reproduction.[2] Each spore type is very host specific, and can typically infect only one kind of plant.

1. RUST DISEASE IN PLANTS LIFE CYCLE AND CONTROLS FAIDURAHMAN KALATHINGAL STEM RUST LEAF RUST STRIPE RUST

2. INTRODUCTION Rusts  are plant diseases caused by  pathogenic   fungi  of the order  Pucciniales  (previously known as Uredinales ). An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus  Puccinia , are currently accepted. [1]  Rust fungi are highly specialized plant pathogens with several unique features. Taken as a group, rust fungi are diverse and affect many kinds of plants. However, each species has a very narrow range of hosts and cannot be transmitted to non-host plants. In addition, most rust fungi cannot be grown easily in pure culture. A single species of rust fungi may be able to infect two different plant hosts in different stages of its life cycle, and may produce up to five  morphologically  and  cytologically  distinct spore-producing structures viz.,  spermogonia ,  aecia ,  uredinia ,  telia , and  basidia  in successive stages of reproduction. [2]  Each spore type is very host specific, and can typically infect only one kind of plant. FAIDURAHMAN KALATHINGAL

3. Rust fungi are obligate plant pathogens that only infect living plants. Infections begin when a spore lands on the plant surface, germinates, and invades its host. Infection is limited to plant parts such as leaves, petioles, tender shoots, stem, fruits, etc. Plants with severe rust infection may appear stunted,  chlorotic  (yellowed), or may display signs of infection such as rust fruiting bodies. Rust fungi grow  intracellularly , and make spore-producing fruiting bodies within or, more often, on the surfaces of affected plant parts. Some rust species form perennial systemic infections that may cause plant deformities such as growth retardation,  witch's broom , stem canker, galls, or hypertrophy of affected plant parts. Rusts get their name because they are most commonly observed as deposits of powdery rust- coloured or brown spores on plant surfaces. FAIDURAHMAN KALATHINGAL

4. TYPES OF RUSTS LEAF RUST : Puccinia triticinia STEM RUST : Puccinia graminis STRIPE RUST : Puccinia striformis FAIDURAHMAN KALATHINGAL

5. STAGES OF SPORES They are macro cyclic five different stages of spores : On cereal: Teliospores Basidiospores Uridinospores Alternate host: Pycniospores Aeciospores FAIDURAHMAN KALATHINGAL

6. STEM RUST FAIDURAHMAN KALATHINGAL Parts of plant infected: Commonly affects stems leaf sheaths, and leaf blades; occasionally will affect part of the head. Shape and distribution of lesions: Oval-shaped or elongated blister-like lesions scattered on affected tissues, lesions visible on both sides of leaf. Lesion color: Orange-red Degree of damage: Tearing of outer layers of plant tissue that is visible without magnification.

7. LEAF RUST FAIDURAHMAN KALATHINGAL Parts of plant infected: Commonly occurs on leaf blades, but may also affect leaf sheaths; infections of stems and heads are rare. Shape and distribution of lesions: Round or slightly elongated blister-like lesions scattered on affected tissues. Lesion color: Brown Degree of damage : Tearing of outer layers of plant tissue rare, visible with magnification.

8. STRIPE RUST FAIDURAHMAN KALATHINGAL Parts of plant infected: Commonly affects leaf blades, occasionally observed on heads when disease is very severe; infection of leaf sheaths or stems is rare Shape and distribution of lesions: Small, roun d blister -like lesions that merge to form stripes Lesion color: Yellow- orange Degree of damage: No tearing of outer layers of plant tissue Identification

9. LIFE CYCLE FAIDURAHMAN KALATHINGAL Meiosis Land on alternate host on the upper surface of the leaf Flexuous hyphae Carried out by insects

10. FAIDURAHMAN KALATHINGAL

11. IDENTIFICATION OF RUST FAIDURAHMAN KALATHINGAL Differentiating the rust diseases can be difficult, but with practice they can be reliably identified. Begin by considering broad characteristics such as which plant parts are affected Figure 1) or arrangement of the blister-like lesions on plants. These characteristics will often separate one or more of these diseases quickly. Continue by examining less obvious charac - teristics including lesion size, shape, and color to either confirm the diagnosis or separate the more similar diseases. For example, stripe rust is the only one of these diseases to have the blister- like lesions organized into stripes on the leaves (left). If the lesions are scattered on the affected plant parts, both stem rust and leaf rust are a possibility and additional characteristics must be considered. Leaf rust typically causes small, round lesions on the leaf blades and leaf sheaths. In comparison, stem rust causes oval or elongated lesions and is capable of infecting nearly all aboveground parts of the plant, most notably the true stems (Figure 2).

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13. CONTROL OF RUST DISEASE FAIDURAHMAN KALATHINGAL CONTROLS: Remove all the infected part and destroy them. Clean away all the debris between plants to prevent spreading. Avoid splashing water on the leaves. Seed fertilizer treatment. PREVENTION: Dust plant with sulphur early in the season. Space your plant for good aeration. Avoid wetting the leaves when watering plants. There are many fungicides also.

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