Báo cáo nghiên cứu khoa học " CITRUS GREENING DISEASE (HUANGLONGBING) " pdf

CITRUS GREENING DISEASE (HUANGLONGBING) NGUYEN VAN HOA SOUTHERN FRUIT RES. INSTITUTE Assumptions in 2002: Huanglongbing and Diaphorina citri evolved in south Asia — in the region that includes Afghanistan, Pakistan and northwest India — but the disease was possibly first noticed in southeast coastal China Eastward spread of the disease and vector to East and Southeast Asia occurred over the past 100 to 200 years — mostly through human activities This spread is continuing through Indonesia towards Australia and Oceania Graphic maps: http://www.worldatlas.com Westward spread ‘occurred’ to Arabia and Réunion Speculation & Developments in 2004: Citrus evolved 60 million years ago in eastern Gondwanan regions that now form parts of the Arabian Peninsula, India and Australasia. The original host of huanglongbing is or was asymptomatic Graphic maps: http://www.worldatlas.com Huanglongbing and Diaphorina citri evolved in to the north west of where these regions The original host of huanglongbing is or was asymptomatic Glycosmis and Oxanthera are species of Citrus 2002: Diaphorina citri occured in South America (since the 1940s) and in North America (since 1998 in Florida) – but huanglongbing had not been recorded in either region 2003/04: Huanglongbing, possibly Liberibacter asiaticus, found in Brazil Graphic maps: http://www.worldatlas.com Cultivated region Area (ha) Varieties Mekong river delta 34.000 Sweet orange, King mandarin, Nam roi pumelo, Tieu mandarin, Tau Lemon, Tac. DongNai river delta 400 TanTrieu pumelo Hương Thuy - HuongTra- Hue 300 Thanh Tra pumelo Huong Son- HaTinh & Tuyen Hoa 2500 PhuTrach pumelo, Bu orange Ham Yen - Bac Giang (Tuyen Quang) Ha Giang 500 Sweet orange and Mandarin Yen Binh, Doan Hung - YenSon 600 Doan Hung pumelo Planning and Statistics Inst., 1994 Main regions for some special citrus fruit varieties in Vietnam Area (ha) Production (Ton) Yield (ton/ha) 1995 1998 % 1995 1998 % 1995 1998 % Whole country 55589 67465 121.36 362349 378957 104.58 6.51 5.61 86.17 The North 14308 37985 265.48 57404 80428 140.10 4.01 2.12 52.89 The South 41299 43984 106.28 306491 298636 97.46 7.42 6.87 91.50 Northeast 4824 10105 209.47 147147 34282 232.46 3.05 3.39 112.62 Central- North 6148 7743 125.94 23243 22661 97.49 3.78 2.92 77.24 Southeast 263 1485 564.63 3984 6310 158.38 15.14 4.24 28.00 Mekong Delta 40579 41267 101.69 301308 286636 95.13 7.42 6.94 93.53 (Courtesy by Ha Minh Trung, 2001) Table 1: Citrus production in Vietnam in 1995 and 1998 Since late 1994, after the survey by Dr. Aubert (Cirad – Flhor) on Nov. 1994 and by Prof. Bove and Dr. Garnier (INRA)( Feb, 1995), the Greening disease was detected and the causal organism was identified as a gram negative bacterium (Candidatus Liberibacter asiaticus). In fact, the disease has occurred since early of 1960’s and the incidence was from 1 to 5%. During this time, the technique for fast multiplication was grafting. With this technique, every year, they supplied 1 million of non free-disease seedlings to the farmers in the region, which lead to 50-60% incidence of orchard’s infection (Vu Khac Nhuong, 1997). After 1975, in the North of Vietnam, the incidence of the disease was around 60-100%. Of them, 30-40% citrus orchards have not beard any fruit. 12.00013.51313.78114.68016.85216.526Area (ha) 200019991998199719961995Year Table 2: Citrus cultivated area at Cantho province (1995 to 2000)  Average reduction of the citrus area per year is 1,000-2,000 ha Citrus cultivated area (ha) Year Cultivar 1992 1995 1998 Orange 3,192 3,959 2,345 Mandarin 1,756 1,952 1,279 Pumelo 423 577 1,600 Table 3: Citrus cultivated area at Vinhlong province (1992 to 1998) Hong, 2000 reported that bacteria made the trees lack of mineral nutrients, such as reducing 70% of Zine in comparison with healthy one, Calcium reduced 29%. The loss due to this disease has not been calculated properly, however, the approximately analysis showed that, at Cantho (main province for citrus), the lost come upto 15 tons/ha on sweet orange, 13 tons/ha on King mandarin and 9 tons/ha on Duong mandarin (Chau et al, 2001). It cause a lot of damage to citrus industry, due to systemic infection and made damage to phloem tissues of the tree, interfere the nutrient flow which lead to nutrients’ deficiencies in leaf, fruit, root system, etc. and finally the tree no more bearing and die. [...]... leaf Mottling symptoms on citrus leaves Motling symptoms on citrus leaves due to Greening disease Leaf becomes yellow, small in size, upright growth, vein corking and like zine difficiency Mottling symptoms Mexican lime Citrus aurantifolia Hanh: Citrus microcarpa Corky vein Pumelo: Citrus grandis (L.) Citrus maxima Citrus reticulata Blanco Citrus grandis (L.) Sweet orange (Citrus sinensis) Aborted seed... Bacterium & a Virus in Citrus Greening + CYMV 1000 bp 750 bp CYMV 680 bp 250 bp Greening 750 bp Stratergy for controlling of citrus Greening Tolerant/Resistance Citrus Resistance to vector HLB C Liberibacter asiaticus Control through change the transmittion characteristics of the vector? Diaphorina citri Chemical treatment Biological control CONTROL MEASURES 1 Seedlings used must be a free -disease seedling,... Huanglongbing disease Individual spylla dotted on NMC for DNA hybridization Grind and hybridize Detection of greening bacterium in psyllid vector using 2.6 kb probe Detection of viruses, viroids and bacteria by DNA-DNA hybridization Detection of Greening disease using from samples collected from different locations, using probe 2.6 kb for DNA-DNA hybridization 700bp Screening of different isolates of citrus. .. through shoot tip grafting, grow under the double doors green house and certified However, this is the free -disease seedling, but not the resistant one So that we have to follow the control measures for vector 2 Grow different types of trees and scrub as a wind break to prevent the reinfection of citrus Greening from surrounding orchards 3 Control the young shoots, it should be 3 to 4 flushes period per... different isolates of citrus for detecting greening bacterium by PCR Lane 1 – 1kb DNA ladder Lane 2 – IARI isolate 1(ISRI) Lane 3- IARI isolate 2(Vasant hostel) Lane 4 – IARI isolate 3(Glass house) Lane 5- Nagpur mandarin field isolate Lane 6 – Nagpur musambi field isolate Lane 7- Jalna moosambi field isolate Lane 8 – Buffer control Candidatus Liberibacter asiaticus Greening bacterium as detected in extracts...120 Yield (%) Yield lost (%) Sweet oranget King maandarin 100 Duong mandarin 80 60 29,02 19,12 40 26,99 19,43 20 25,78 16,45 0 Grade 5 + Grade 3+ Disease severity Percentage of fruit yield lost due to HLB in Cantho (%) Courtesy by Chau & Hong, 2003 In 1995, one survey in Vinhlong province was conducted by SOFRI and Vinhlong provincial staffs Out . symptoms Hanh: Citrus microcarpa Citrus maxima Corky vein Pumelo: Citrus grandis (L.) Mexican lime Citrus aurantifolia Sweet orange (Citrus sinensis) Citrus reticulata Blanco Citrus grandis. trees: 1-5% tree infection (In 49 ha survey) Motling symptoms on citrus leaves due to Greening disease Healthy leaf Mottling symptoms on citrus leaves Leaf becomes yellow, small in size, upright growth,. CITRUS GREENING DISEASE (HUANGLONGBING) NGUYEN VAN HOA SOUTHERN FRUIT RES. INSTITUTE Assumptions in 2002: Huanglongbing