virus diseases of sugar beet (virology) .pptx

Virus Diseases of sugar Beet are mentioned briefly in the above ppt

1. VIRUS DISEASES OF SUGAR BEET ( Beta vulgaris ) GADDE SRIHAASA 27224062025

2. A   sugar beet   is a plant whose root contains a high concentration of   sucrose   and that is grown commercially for   sugar   production.   the first data on the yellows disease were recorded in France Sugar beet viruses clearly divide into two main groups Group 1 beet curly top virus beet mosaic virus the beet yellows virus Group2 beet mild yellowing virus beet western yellows virus beet necrotic yellow vein virus

3. Beet curly top virus BtCuTpV is widespread in arid and semiarid western parts of North and South America, Iran, India 1988, Turkey, and in the Mediterranean countries from which it seemingly originated1981. BtCuTpV is isometric, 20 nm in diameter The virus likely contains single-stranded DNA with no information on its protein. The TIP of BtCuTpV in sugar beet root sap is 80°C; the DEP 1 x 10-3; and the LIV at 24°C is 8 days BtCuTpV is serologically strongly immunogenic Since phloem restricted, it occurs in low concentrations in the plant.

4. BtCuTpV has a broad host range. In addition to sugar beet, natural hosts include spinach, tomato, potato, cucumber, tobacco, bean, flax, clover, parsley, and both ornamental and woody plants The virus has been experimentally transmitted via leafhoppers into over 300 species in 44 dicot families (Bennett, 1971), which include Chenopodiaceae, Compositae, Cruciferae, Leguminosae, and Solonaceae. Typical symptoms of BtCuTpV infection in young sugar beet leaves appear as vein clearing;during growth, leaves twist upward and inward with general dwarfing and yellowing. Wart-like formations develop on the veins on the lower leaf surface. Losses can be reduced by the use of resistant varieties; Adopting sanitary measures including the eradication of susceptible weeds and susceptible volunteer crop plants from a previous planting; Regulating the time of planting in order to avoid the main flights of the beet leafhopper; Use of barriers of trap crops and early removal and destruction of infected plants. Spraying malathion (2ml/ litre of water) controls the population of beet leaf hoppers.

5. BEET MOSAIC VIRUS Family : Potyviridae BtMV , first reported in 1898 in garden beets in northern France and near Paris, was soon noted in other European countries (Denmark, Germany, Sweden) and in the U.S. BtMV particles measure 730 x 13 nm Physical properties include a TIP of 55 to60°C, a DEP of 4 x 10 -3 , and LIV at 20°C of 24 to 48 hours. BtMV is immunogenic and serologically related to Bean yellow mosaic virus and Potato virus Y The moderate host range for BtMV includes all cultivated sugar beet cvs ., Beta vulgaris subsp. maritima , Amaranthus retroflexus , Campanula ranunculoides , Chenopodium album, Delphinumconsolida , Melilotus officina /is, Papaver somniferum , Spinacia oleracea , Stellaria media, Trifolium incarnatum , and T. repens

6. Initial symptoms of BtMV infection are numerous small yellow spots and blotches on one or several central leaves. A light mosaic and mottle occurs on young leaves as disease develops. Leaflets with initial symptoms are stunted, with curling and rolling of leaf margins and leaf tip necrosis. In severe cases, diseased leaves roll into a tubular shape. Planting beet varieties that are resistant or tolerant to BMPV can help reduce the impact of the virus. managing weed populations implementing measures to control aphid populations is crucial, as these insects are the primary vectors for BMPV. This can include using insecticides or natural predators of aphids. Removing and destroying infected plant debris can help reduce the sources of the virus.

7. BEET WESTERN YELLOW VIRUS Family : Luteoviridae BtWsYsV , thus far recorded in North America, Europe and Asia, is probably spread worldwide BtWsYsV is isometric, 26 nm in diameter has a single-strand RNA species of 1900 kDa The TIP of BtWsYsV is 65°C; the DEP is 118; and the LIV at 24°C is 16 days BtWsYsV infects a broad host range of 150 species in 23 dicot families Economically important hosts include sugar beet, cabbage, cauliflower, flax, lettuce, pepper, radish, spinach , sunflower , tomato, and watermelon BtWsYsV infects many plants, but causes the most severe symptoms on sugar beet and lettuce. Sugar beet plants infected with BtW s Y s V expresses initially partial, and later general, leaf yellowing

8. Lettuce leaves express different degrees of yellowing in the field. Initial symptoms of mild interveinal yellowing become more pronounced and finally result in marginal leaf necrosis. Eight aphid vectors transmit BtWsYsV persistently, and Myzus persicae is most important.. Several measures applied simultaneously may reduce losses due to this virus. (1) Eliminate all weed plants, especially overwintering ones. (2) Chemical control of vectors with an appropriate aphicide . (3) Apply biological control measures aimed at preventing development of aphid populations.(4) Grow more tolerant or resistant sugar beet cultivars.

9. BEET NECROTIC YELLOW VEIN VIRUS The BtNc YVV disease was first recorded in 1954 and 1957 in Italy The BtNcYVV 20 nm-wide, rod-shaped, multicomponent particles are characterized by groups based on length. . Isolates from France are placed in four groups of 85, 100, 265, and 390 nm long. Isolate from Yugoslavia are placed in five groups of 44 to 125, 133 to 259, 276 to 400, 418 to 569, and 586 to 769 nm long . Isolates from Japan are placed in three groups of 65 to 105, 270, and 390 nm long BtNcYVV particles have a single coat protein of 21 kDa and four species of single-stranded RNA of 2300, 1800,700, and 600 kDa Japanese isolates are: TIP is 65 to 70°C; DEP is I x J0-4; and LIV at 20°C is 5 days ( Tamada and Baba, 1973). For Yugoslavian isolates TIP is 70 to 75°C; DEP is 1 X 10 -5 ; and LIV is 6 days.

10. Both sugar and fodder beets are susceptible to BtNcYVV , which also infects spinach and species of the Chenopodiaceae. Seventeen other plant species have been inoculated artificially withBtNcYVV ( Putz , 1977), of which Amaranthus hybridus , Beta macrocarpa , Beta vulgaris subsp. cicla , B. vulgaris subsp. esculenta , Chenopodium album, C. amaranticolor , C. foetidum , C. hybridum , C. quinoa, Nicotiana clevelandii , N. tabacum ( cvs . Havana and White Burley), Stellariamedia , and others have been confirmed. Symptoms in BtNcYVV -infected sugar beets include yellow, roundish patches in the fields, occurring in smaller depressions in which the water remains following heavy rains. During developmentof disease in the summer, these yellow patches merge and enable easy detection of infected spots .

11. No practice or economically justifiable measures currently enable substantial reductions of damage due to this disease. Several measures that jointly contribute to reduction of virus occurrence and spread are recommended. Sugar beet plants should not be grown on moderately or severely contaminated soils. Fields with water drainage problems should not be selected for sugar beet production. Irrigation should be avoided in areas of known disease incidence. Deep tillage ( subsoiling ) should be done as a normal cultural practice. Fields with high underground water levels should be drained to eliminate excess water and to reduce the dangers of infection.

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