Bacterial wilt and bacterial blight of rice K R.pptx

Bacterial wilt and bacterial blight of rice K R.pptx

1. BACTERIAL WILT AND BACTERIAL BLIGHT OF RICE K R MICRO NOTES 1

2. BACTERIAL WILT Bacterial wilt is a disease or disease symptom caused by plant- pathogenic bacteria in which there is dropping off leaves and stems or plant die back from lack of water ( inadequate water supply or excessive transpiration ) Bacterial wilt is a complex disease that occur in plants such as solanaceae family like tomato, potato,beans, eggplant,etc And cucurbitaceae family like cucumber, squash, muskmelon, pumpkin, watermelon, etc. Bacterial wilts are caused by the pathogens Erwinia tracheiphila in cucurbitaceae and Ralstonia solanacearum in solanaceaE family. K R MICRO NOTES 2

3. Bacterial wilt In solanaceae Bacterial wilt in cucurbits K R MICRO NOTES 3

4. Bacterial wilt in solanaceaE Bacterial wilt in solanacous crops is also called as southern bacterial wilt or southern wilt As it was 1 st found in the southern United States. Bacterial wilts of tomato, eggplant, and Irish potato caused by R. solanacearum were among the first diseases that Erwin Frink Smith proved to be caused by a bacterial pathogen. This disease is caused by the soil-borne bacterium Ralstonia solanacearum. K R MICRO NOTES 4

5. Casual Organism: Ralstonia solanacearum (formerly called Pseudomonas solanacearum ) Ralstonia solanacearum is a gram-negative ,motile ,rod shaped, soil borne Bacterium. The organism grows aerobically and does not form endospores Agar colonies are small, smooth ,wet, shining become brown through formation of black water soluble pigment. Electron microscopic image of Ralstonia solanacearum K R MICRO NOTES 5

6. Disease cycle K R MICRO NOTES 6

7. Symptoms: Leaflets take a bronze colour, shrivel, leaves may wilt And die. The vascular system turn brown. In damp soil bacterial masses may exude (to cause to ooze or spread out in all directions )to eyes of tubers. Decay of tuber continous after harvest. K R MICRO NOTES 7

8. Bacterial wilting in potato K R MICRO NOTES 8

9. Control: Using certified seed and avoid infested soil. Sulfer-Limestone treatment is used for bacterial wilt in potato, if soil is of sandy type. This treatment is not applicable to clay soil. K R MICRO NOTES 9

10. BACTERIAL wilt in cucurbits Bacterial wilt is a common and often destructive disease on muskmelon and cucumber. Squash and pumpkin are susceptible but are not affected as severely. the disease is rarely a problem on watermelons. The disease occurs throughout the United States and Canada.
IT is more common in the northern states than in the south. Wilt has been reported in Europe, South Africa, and Japan. K R MICRO NOTES 10

11. Causal organism Erwinia tracheiphila gram-negative, rod-shaped, motile bacterium. On NA medium, E. tracheiphila colonies are generally small, circular, viscous, and hyaline or white in color. Vector It is transmitted by insect vectors, primarily the striped cucumber beetle. Erwinia bacteria. Coloured scanning electron micrograph (SEM) Cucumber beetles are highly attracted to cucurbit flowers. Erwinia tracheiphila can enter the vascular system through floral nectaries. K R MICRO NOTES 11

12. Disease cycle K R MICRO NOTES 12

13. Symptoms Leaves first appear dull green, wilt during the day and recover at night. Leaves eventually Turn yellow and brown at the margins, completely wither and die. The speed of wilting varies by crop, cucumbers and melons WILT And die
Pumpkins take up to two weeks to wilt completely . Summer squash may continue to produce for several weeks, even when infected. wilt progresses down the vine until the entire vine wilts or dies. If infected vines are cut close to the crown of the plant and the cross-sections pressed together, thread-like strands of bacterial ooze are visible when the two halves are gently pulled apart again K R MICRO NOTES 13

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15. Control Cucumber beetles must be controlled by Using appropriate insecticide. Use crop rotation method to reduce beetle numbers in adjacent areas. Rogue infected plants(identifying and removing diseased or infected plants). Spunbonded row covers are used to avoid beetles. Using resistant variety of seeds. K R MICRO NOTES 15

16. BACTERIAL BLIGHT of rice Bacterial blight is one of the most serious diseases of rice. It can occur in both tropical and temperate environments, particularly in irrigated and rainfed lowland areas. In general, the disease favours temperatures at 25-34°C, with relative humidity above 70%. It is commonly observed when strong winds and continuous heavy rains occur, allowing the disease-causing bacteria to easily spread through ooze droplets on lesions of infected plants. The disease was first reported from Japan in 1881.
The bacterial leaf blight (BLB) of rice had been known in Japan as an endemic disease since 1881. K R MICRO NOTES 16

17. Later, its incidence in severe form was reported from India also. In Japan the disease is responsible for a loss of 30% or more annually. In India the damage has been estimated to vary from 6 to 60%. Bacterial blight is a very common and widespread disease of paddy in Asia.
In India, the disease was first reported in 1951 from Bombay. The rapid spread of the disease to the northern parts of the country was attributed to the introduction of highly susceptible variety Taichung Native (TN) 1, In Punjab. K R MICRO NOTES 17

18. CAUSAL ORGANISM Xanthomonas oryzae It i s an aerobic, rod shaped, non capsulated, non-spore forming, gram negative bacterium. 0.5-0.8 x 1-2 μ in size. It is motile with a single polar flagellum.
The bacterium produces waxy yellow colored colonies on agar medium and is incapable to reduce nitrates.
The optimum temperature for its growth is 28 -30° C. K R MICRO NOTES 18

19. Disease cycle K R MICRO NOTES 19

20. Symptoms The bacterium causes either wilting of plants or Leaf blight, wilting is known as ‘ Kresek ’. Kresek results in the death Of plant or wilting of only a few leaves. margins of the leaves and along the midrib, water- soakeded translucent spots appear in blight phase And sometimes appear on leaf sheath. On seedlings, infected leaves turn grayish green and roll up. As the disease progresses, the leaves turn yellow to straw-colored and wilt, leading whole seedlings to dry up and die. K R MICRO NOTES 20

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22. Control Soak seeds for 12 hours in 0.025% solution of AgRimycin (15% streptomycin, 1.5% Oxytetracyclin and 83.5%inert matter)+0.05% wettable ceresin ( It is a wax derived from ozokerite and used as substitute for beeswax) and give hot water treatment (52-54°C for 30 minutes). Spray Agrimycin or Streptocycline (250 ppm) alternately with a copper fungicide to check secondary spread. Using resistant variety of seeds. K R MICRO NOTES 22

23. References: Plant Pathology – Second Edition-R.S. Mehrotra, Ashok Agarwal
Plant Diseases – Ninth Edition R.S.Singh Plant Pathology – John Charles Walker
www.missouribotanicalgardEn.org
www.apsjournals.apsnet. Org www.researchgate.net K R MICRO NOTES 23