Nutrition and HLB Management, 70 Years Experience from China Yulu Xia North Carolina State University Ron Sequeira USDA APHIS PPQ CPHST Merida, Mexico July 21, 2010
Content The Big picture Why the topic? A Brief on Citrus production, HLB, and ACP in China Nutritional approach for HLB management in China, 70 years experience Overall situation Selected studies since 1937 Field practice and lessons learned Conclusions and Questions
Why the topic? Using nutritional approach gathers momentum in Florida.»Nutrition makes grove look good (next slide)»the long time before the symptom shows up after the initial infection» Old tree never die, just fade away
A four-year old groves with 100% infested HLB plants. But it looks good in the spring with good fertilization
Why the topic? Scientific community and growers»we must provide the answers»experience in China may shortcut our experience»china experienced the same frustration»save our $, more importantly, time
The Big picture A Brief on Citrus Production, HLB, and ACP in China
Citrus Growing Area in China China has a much larger citrus production area.
ACP The Reported Big Pictures in at least ACP 11 prov Occu.
The Major HLB The HLB Big BeltPictures Occurrence HLB Occur. HLB mainly occurs in the southern costal provinces: Guangdong, Guangxi, and Fujiang
The first observations of diseased citrus corresponding to what is now recognized as HLB were in southern China in the late 19th century. In the mid-20th century, the Chinese researcher K.H. Lin provided a scientific description of HLB and demonstrated its infectious nature. --- National Research Council, Strategic Planning for the Florida Citrus Industry: Addressing Citrus Greening Disease (Huanglongbing), May 2010
K. H. Lin promoted in China, in the middle of the 20th century, a three-pronged approach to combating HLB after its appearance in a region (i)elimination of liberibacter inoculum by removal of symptomatic trees, (ii) insecticide treatments to keep psyllid vector populations as low as possible, and (iii) production of healthy citrus trees in closed, insect-proof nurseries for new orchards as well as for replacements of removed symptomatic trees
Picture taken in 1930s showing HLB in Chaoshan, Guangdong
Long and diverse citrus production system
Nutritional approach for HLB management in China 70 Years History A Brief of our current projects in China Overall situation Selected studies since 1937 Field practice and lessons learned Conclusions & Questions
Our current projects in China Two grant projects by USDA APHIS APHIS s emphasis on method development My background in ACP back in 1980s, in together with Andrew Beattie ACP/HLB Field Method Development and Outreach Chinese HLB/ACP Literature Inventory
Collaborators: South China Agri. Univ. (SCAU) Fujian Academy of Agri. Sci (FAAS) Guangxi Citrus Research Insti. (GCRI) Guangdong Entomological Insti. (GEI) The Citrus Institute, Chinese Academy of Agri Sci.
Survey SCAU, FAAS, GCRI The epidemiological significance of Murraya paniculata and Murraya spp. - FAAS Microbials and Plant Immune Activation - FAAS Dynamics of Reset Plants Migration patterns of ACP - SCAU Oils and Soaps for Field Management - GEI Best Practices for ACP/HLB Management GEI & Additional Insect Vectors and Host plants - SCAU Chinese literature review and inventory GEI ACP insecticide resistance and resistance management (GCRI)
Nutritional approach for HLB management in China 70 Years History A Brief of our current projects in China Overall situation Selected studies since 1937 Field Practice and Lessons learned Conclusions and Questions
A Review of research on nutrition for HLB management since 1937 - Overview Using nutritional approach for HLB management had been proposed since 1930s There were fierce debates on the issue since 1950s all the way to 1980s Numerous field studies, area-wide programs, and surveys have been conducted, no indication of effectiveness Difference in response to nutrition among citrus species/cultivars
Selected studies First study was conducted during the period of 1937 1941 by professor CHEN Che Poh, in the middle of the world II (Japan occupied China) CHEN QB: 1943. A report of a study of Huanglongbing in Chaoshan. Quarterly Bulletin of New Agriculture. 142 175
CHEN QB: 1943. A report of a study of Huanglongbing in Chaoshan. Quarterly Bulletin of New Agriculture. 142 175 Nutritions zinc sulphate (ZnSo 4 ), copper sulphate (CuSo 4 ), boron(h 3 BO 3 ), calcium sulphate (CaSo 4 ), ferric sulphate(feso 4 ), potassium hydrophosphate (KH 2 PO 4 ), magnesium sulphate(mgso 4 ), soy bean residue, etc. Application methods surface spraying trunk drill soil application
Experiment 1(20 th August 1937 July 1938) Nutrition elements such as zinc sulphate (ZnSo 4 ), copper sulphate (CuSo 4 ), boron(h 3 BO 3 ), calcium sulphate (CaSo 4 ), ferric sulphate(feso 4 ), potassium hydrophosphate (KH 2 PO 4 ), magnesium sulphate(mgso 4 ) were filled (powder) into trunk Table 1. Dose of nutrition element by trunk application of HLB trees Nutrition elements Dose (g) Treatments ZnSo 4 CuSo 4 H 3 BO 3 CaSo 4 KH 2 Po 4 MgSo 4 0.5 0.2 0.1 1.5 1.0 0.2 Total dose /tree (g) Ⅰ + + + + + + 3.5g Ⅱ + + + + + 3.3g Ⅲ + + + + 2.3g Ⅳ + + + 0.8g Ⅴ + + 0.7g
Experiment 1(20 th August 1937 July 1938) Nutrition elements such as zinc sulphate (ZnSo 4 ), copper sulphate (CuSo 4 ), boron(h 3 BO 3 ), calcium sulphate (CaSo 4 ), ferric sulphate(feso 4 ), potassium hydrophosphate (KH 2 PO 4 ), magnesium sulphate(mgso 4 ) were soil treated Table 2. Dose of nutrition element by soil application Nutrition elements ZnSo 4 CuSo 4 H 3 BO 3 CaSo 4 KHPo 4 MgSo 4 Solution concentration 10% 5% 4% 15% 6% 3% Treatments Dose/treatment (liter) Ⅰ + + + + + + 5 Ⅱ + + + + + 5 Ⅲ + + + + 4 Ⅳ + + + 4 Ⅴ + + 3 Ⅵ + 3
Result of Experiment 1 Treatments Trunk treatment Soil treatment Trunk treatment Soil treatment Trunk treatment Soil treatment Trunk treatment Soil treatment Trunk treatment Soil treatment Trunk treatment Soil treatment Sample tree number and HLB situation CK CK.N. 1/11 D 2/4 D 3/1 D 3/4 D 4/2 D 4/9 D 4/10 D 4/5 N 1/40 X 1/42 X 2/43 D 2/45 D 2/46 X 2/47 D 1/1 N 2/8 X 3/5 X 3/7 D 6/6 O 6/7 X 6/8 X 3/10 X 4/6 N 3/35 D 3/42 D 8/6 D 8/2 D 8/6 X 8/4 X 1/3 N 1/4 X 3/11 X 4/1 D 5/4 D 5/6 D 6/5 D 6/9 N 5/5 N 1/11 X 1/19 D 1/24 X 3/4 D 3/11 X 3/3 X 1/6 N 1/5 D 1/6 D 5/8 D 5/11 X 6/1 D 6/2 D 1/13 D 3/3 N 3/24 X 3/29 X 3/54 X 2/34 X 3/9 D 1/34 X 1/7 N 1/9 N 2/3 D 2/6 D 6/4 D 6/10 D 6/12 D 2/7 D 1/10 N 3/30 O 1/8 X 1/22 X 1/26 D 1/30 X 1/9 D 1/33 N 1/7 D 1/8 N 2/9 N 4/8 D 5/? D 5/7 N 1/12 N 2/10 N 2/41 X 1/36 X 2/35 X 2/7 X 3/25 X 3/37 O 1/16 N
Experiment 2 (2 nd June to 29 th October 1939) Zinc sulphate (ZnSO 4 ) spraying on 12 mid-term HLB diseased citrus trees two times ( 2 nd and 16 th June 1939), 12 the same diseased trees without treatment as control. Before 29 th October 1939, there is no difference between treatment and CK (Table 4). Table 4 HLB control effect of Zinc sulphate spraying HLB diseased trees Treatment Number of tree Situation of trees from 2 nd June to 29 th October 1939 Renewing Invariant Deteriorating Dead ZnSO 4 spraying 12 2 4 3 3 CK 12 3 2 3 4
Experiment 3 (30 th August 1940- April 1941) Spraying and painting experiments using former compounds or elements of nutrition were applied in HLB citrus plants in Xitouyanting orchard in August 1940. Every treatment was used 2 litres solution containing compounds or elements according to Table 5, then sprayed or painted them on branches and leaves of 4- year old citrus trees (Number of trees was unknown) which were infected with HLB during the initial diseased stage.
A large number of field studies were conducted using nutrition/fertilization and other cultural practices for managing HLB from early 1940s to 1980s in China, no long-term success or benefit had been demonstrated.» LIN KH 1977. The Key Issues in Management of HLB. Bulletin of Citrus Technology and Technology 3-4: 28 37» ZHAO XY & YH JIANG. 1986. Effective HLB management is a key step in Liuzhou s citrus production Chinese Southern Fruit. 2: 21-22
Nutritional approach for HLB management in China 70 Years History A Brief of our current projects in China Selected studies since1937 Field practice and lessons learned Conclusions and Questions
Field Practice and Lessons Learned The three-pronged approach, e.g. 1) using pathogen free seedlings, 2) removal of the infested plants, and 3) control of vector insects, was proposed by Dr. Lin and other researchers in 1950s. However, this approach was not widely adopted in China, even at minority sometimes, using nutrition and other culture practice was repeatedly advocated by growers and event scientists.» LIN KH 1956, 1957, and 1962
A test of removal infested tree, conducted by Dr. Lin KH. 08-1956 to 03-1961 # of Citrus Tree Removal Area Control Total plants at start 229 197 Total infested plants at start 11 (4.8%) 13 (6.6%) Newly Infested - 1958 8 (3.5%) 19 (9.6%) Newly infested - 1961 67 (29.2%) 112 (56.8%) LIN KH 1962. Ten Year Debate on HLB and the Future. The South Daily. March 29, March 30, March 31, 1962.
LIN KH 1956. Observation on yellow shoot of citrus: aebiological studies of yellow shoot of citrus. Acta Phytopathologica Sinica 2: 1 42. LIN KH 1962. Ten Year Debate on HLB and the Future. The South Daily. March 29, March 30, March 31, 1962.
1950s Several influence citrus growers (so called Model Growers), the best known case, Mr. GUO Kun Chen, claimed that they had cured HLB on their groves by using nutrition approach, in together with other cultural practices in early 1950s. Other scientists, mainly plant physiologist and crop scientist who didn t involved much with the disease, joined the camp.
This view became widespread by the late of 1950s, lead to local government sponsored Mass Area-wide of HLB Management Program, mainly by increasing fertilization, cutting the heavily infested branches, and removing decayed roots, across the huge HLB occurrence area in southern China, especially in Fujian and Guangdong Provinces, started in 1958. As expected, the program failed. HLB became even more serious.
1960s and later Nutrition and other cultural practice have been practiced among the small-scale, family-own groves. The three-pronged approach is not widely used by these growers. Few scientists, especially those who didn t conduct field study on the issue, advocated the approach. E.g. HOU XY 1985, distinguished botanist and An Academician of CAS. This is the main reason that HLB is still a problem there.
Credit: Bai XJ
The three-pronged approach adopted by the bigger, professional growers, and works well across China. HLB Rate 0.25 23.45% 0.2 0.15 0.1 0.05 0 8% 5% 1% 1% 0.44% 0.23% 0.13% 0.05% 1 2 3 4 5 6 7 8 9 Year: 1 = 2001 HLB Occurrence in Li Xing Citrus Plantation, Guangxi Prov. credit: Bai XJ
WU DY 2010 HLB and Integrated Management. Pp. 177. Guangdong Scientific Press. LIN KH 1962. Ten Year Debate on HLB and the Future. The South Daily. March 29, March 30, March 31, 1962.
Other major studies and references LIN K.H. 1956. Acta Phytophylacica Sinica. 2(3): 2-16** LIN K.H. 1963. Acta Phytophylacica Sinica. 2(3): 243 251** ZHAO X.Y. 1962. Scientia Agricultura Sinica. 7: 8-11** LIN C.K. 1964. Acta Phytophylacica Sinica. 3(3): 233 236. LIN C.K. (Beijing Agri Univ.) 1963. Acta Phytophylacica Sinica. 2(3): 237 242 ZENG M. X.Y. Zhao. 1963.Scientia Agricultura Sinica. 17 20**
Nutritional approach for HLB management in China 70 Years History A Brief of our current projects in China Selected studies since1937 Field practice and lessons learned Conclusions and Questions
HLB is a manageable disease if you follow the principle Nutrition/fertilization is not a short-term makeup, but a dangerous practice.
A more than 200 year-old of Citrus sunki grows well in Guangxi, in spite of the fact that the province is one of the most serious HLB occurrence area in the world Yulu Xia, Ron Sequeira, Ignacio Baez, Yu Takeuchi, and Rui Yang North Carolina State University and USDA APHIS PPQ CPHST Denver, Co June 18, 2010 A more than 200 year-old of Citrus sunki grows well in Guangxi, in spite of the fact that the province is one of the most serious HLB occurrence area in the world (credit: BAI XJ)