The Control Research Progress ofLiberobacter asiaticumin Taizhou City

Jihua YU,Minrong ZHANG,Jian TAO,Lu LU,Xiao YANG,Enguo WANG,Zhiyong YE

1.Plant Quarantine Stations of Huangyan District,Huangyan 318020,China;

2.Plant Protection Station of Linhai City,Linhai 317000,China;

3.Huangyan Agriculture Bureau,Huangyan 318020,China

The Control Research Progress ofLiberobacter asiaticumin Taizhou City

Jihua YU1*,Minrong ZHANG1,Jian TAO1,Lu LU1,Xiao YANG1,Enguo WANG2,Zhiyong YE3

1.Plant Quarantine Stations of Huangyan District,Huangyan 318020,China;

2.Plant Protection Station of Linhai City,Linhai 317000,China;

3.Huangyan Agriculture Bureau,Huangyan 318020,China

After decades of researches and discussions on occurrence regularity and control technology of citrus psyllid(Diaphorina citri Kuwayana)and Liberobacter asiaticum,the occurrence regularity and sampling technique of citrus psyllid in orange forests in Taizhou was defined and the connections between the infection rate and carrying rate of citrus psyllid and Liberobacter asiaticum as well as the correlations between the Liberobacter asiaticum and citrus yield loss were discussed.This paper discussed the warnings of Liberobacter asiaticum and citrus psylid control index,the economic life span of orange forests was then predicted by building the diseases spreading models with different management styles.At last,the paper put forward the comprehensive prevention and control technology and the concept that Liberobacter asiaticum was preventable and controllable.

Liberobacter asiaticum;Citrus psyllid;Occurrence regularity;Disease Spreading models;Control index;Prevention and control technology

T aizhou is located along the southeast coast of Zhejiang P rovince,and the citrus is one of the leading industries of agriculture. Huangyan mandarin orange dated from the Three Kingdoms and flourished in the Tang and Song dynasties, which had 1 700 years of cultural history before present and was the ancestor of the world’s citrus[1-4].Liberobacter asiaticum was the quarantine pest that had fastest spreading speed, heaviest damage,largest hazard and hardest prevention and treatment, meanwhile it was the international scientific and technological problems that had not yet to be conquered in the cur rent[2].Since 2002,Liberobacter asiaticum was firstly introduced to Taizhou,the citrus industry was severely threatened by this disease.A total of 1.9945 million sick trees were cut in Huangyan for 12 years[3].By a series of researches on the disease spreading,vector insect,control index, comprehensive prevention and control technology,a series of comprehensive prevention and control technology formed based on the main prevention and control of Diaphorina citri,which effectively contained the occurrence and damage of Liberobacter asiaticum and promoted the healthy and sustainable development of the citrus industry.To this end,this study revealed the relationships of Liberobacter asiaticum and citrus psyllid,the occurrence and spatial distribution of citrus psyllid,the relationships of Liberobacter asiaticum and yield loss,epidemic regularity and diffusion dynamic model of Liberobacter asiaticum and the prevention and control measures of Liberobacter asiaticum.

The Relationships ofLiberobacter asiaticumand Yield Loss

By surveying the susceptibility ofLiberobacter asiaticumin different varieties from 2003 to 2005,4 main citrus varieties in 25 citrus orchards were investigated.The results showed that the average infection rate ofCitrus reticulataBlanco cv.Tardiferax,Citrus reticulataBlanco cv.Succosa,satsuma orange and Ponkan were 18.99%,25.63%,31.09%and 39.55% respectively,disease index was 9.03,10.32,14.77 and 23.54 respectively.It means that the susceptibility ofLiberobacter asiaticumof main citrus varieties was Ponkan＞satsuma orange＞Citrus reticulataBlanco cv.Succosa＞Citrus reticulataBlanco cv.Tardiferax[5].

By surveying the relationships ofLiberobacter asiaticumand yield loss from 2002 to 2009,the healthy fruit numbers were calculated and the healthy fruit rate were compared in different illness state.The results showed that the healthy fruit rate and fruit amount of single plant decreased with the increase of disease severity[6]. The correlations between different disease severity ofLiberobacter asiaticumand single fruit weight and strains yield was negative,but the correlations with yield loss was positive,and the degree of correlation reached a significant level.The disease severity ofLiberobacter asiaticumwas higher,the single plant weight and strains yield was lower, and the yield loss was larger[7].

The Relationships ofLiberobacter asiaticumand Citrus Psyllid

Studied the relationships of the infection rate and carrying rate of adult citrus psyllid by PCR detection[8-10],the established mathematical model indicated that the correlations between the morbidity ofLiberobacter asiaticumand the carrying rate of citrus psyllid reached extremely significant level. The correlations between the amount of larvae per plants of citrus psyllid and larvae plant rate was significant.The psyllid of citrus became nymph in fall tip period was surveyed in 2006.The dates of the amount of larvae per plants of citrus psyllid and larvae plant rate of 11 orchards were analyzed, and the results showed that the correlations between the amount of larvae per plants of germ-carrying citrus psyllid and larvae plant rate was extremely significant.Meanwhile,the corresponding mathematical model was established[11].

The relationships of citrus psyllid larvae plant rate and the infection rate ofLiberobacter asiaticum.According to the occurrence condition of citrus psyllid andLiberobacter asiaticum,the results showed that in the early stage ofLiberobacter asiaticum,the disease was sporadic or light in the orchard, and the average larvae plant rate of citrus psyllid was less than 10%,which was over 10%in the orchards with middle and heavy morbidity.The correlations between larvae plant rate of citrus psyllid and the morbidity ofLiberobacter asiaticumwere extremely significant by statistical test.The orchards with higher larvae plant rate had higher morbidity,and the related equations was established in order to warnLiberobacter asiaticummorbidity by larvae plant rate[12].

The Occurrence Regularity and Distribution Characteristics of Citrus Psyllid

According to the surveys from 2003 to 2005,the occurrence generation of citrus psyllid was 6 to 7 generation in Huangyan[13].The 1st to 3rdgeneration was more orderly,and the 4thto 7thgeneration had a phenomenon of generation overlapping.The occurrence time of the 1stgeneration was in the early and middle of April,and the wintering adults began to spawn,then eclosion in the later April and early May.The eclosion time of the 2ndgeneration adult was in early July,the 3rdgeneration adult was in early August, the 4thgeneration adult was in early September and the 5thgeneration adult was in middle and later of September. The 4thand 5thgeneration occurred generation overlapping[14].The 6thand 7thgeneration were currently only found in growing stronger saplings or adult trees that the large branches full cut and the flourished late fall branch. Under normal conditions,there was no nymph after early November,but still a few adults.Currently only found adults overwinter,but not clear whether the egg or nymph live overwinter[15].

In September 2006,11 orange fields with different population density of citrus psyllid were investigated and each sample plot was surveyed and records the number of adults per plant. The results determined by aggregation degree index method[16]showed that the distribution characteristics of adult citrus psyllid were different under different population density[15].Low population density appeared low aggregation degree and high population density appeared high aggregation degree. Thus,the spatial distribution of adult citrus psyllid in the citrus was that the aggregation degree increased with the increase of population density,and accord with the negative binomial distribution[17].

Based on the analysis of citrus psyllid population distribution pattern, the optimal sampling method of the number of citrus psyllid surveying was saltatory method and five-point method[18].Meanwhile,the theoretical sampling model of adult citrus psyllid was established[19]in order to determine the sampling number table in different population density and guide prevention and control work according to the psyllid density.The determined prevention policy recommendations was:in the low-density orchards,each orchard checked 50 to 100 plants;in the medium and high density orchards, each orchard checked 20 to 50 plants, which was able to know the occurrence status of the investigated orchards[20].In order to save the investigation time,sequential sampling method could be chosen by using sequential sampling table[21].As prevention decisions of orchards,the survey should be contrast with sequential sampling table,and then stopped the investigation when the cumulative amount of insects reached predetermined indexes.Thereby calculated the average population density,whichprovided a guiding significance for early warning and prevention and control of citrus psyllid[22].

Liberobacter asiaticum vector Control Index and Early Warning Index

According to the study of the relationships between infection rate,yield loss and effective amount of citrus psyllids[23-24],the control index for psyllid in shoot stage of citrus was that the initial stage of new shoots of citrus was the optimal prevention stage for controlling and preventing germ-carrying citrus psyllid.The control index of the amount of germ-carrying citrus psyllid identified as 7.5 per one hundred plants.It means that the control index ofLiberobacter asiaticumwas 10 per one hundred plants of the amount of germ-carrying citrus psyllid.

According to the study of the relationships between infection rate and yield loss[25],the strategic control index forLiberobacter asiaticumwas established[26].Under the allowed loss level, the strategic control index was 1.0%of the infection rate of the whole orchards in the initial stage of illness.It means that if the infection rate exceeded 1.0% in the initial stage of illness,the diseased trees should be eradicated to reduce bacteria source,while overall using drug to prevent the bacteria spreading and infecting adjacent healthy trees.

According to the study of the relationships between germ-carrying rate of citrus psyllid and infection rate ofLiberobacter asiaticum,the prediction technique and early-warning index for germ-carrying rate of citrus psyllid were established.When the infection rate ofLiberobacter asiaticumin the initial stage of illness rose to 1.0%,the germ-carrying rate of citrus psyllid would exceeded 4.0%,which indicated thatLiberobacter asiaticumwould formed a large heavy diffusion damage.Thus,the germ-carrying rate of citrus psyllid could be used to make pandemic alert ofLiberobacter asiaticum.When the detected germ-carrying rate of citrus psyllid exceeded 4.0%,it needed to increase prevention and cure of citrus psyllids in the whole orchards[27-28].

Epidemic Regularity and Diffusion Dynamic Model of Liberobacter asiaticum

The distribution pattern and sampling model of Liberobacter asiaticum

Spatial distribution of Liberobacter asiaticum in premature satsuma orange variety‘Gongchuan’(hereinafter referred to as premature citrus)From 2004 to 2009,data obtained by multistage sampling survey and then determined by the aggregation degree index,the results showed that the spatial distribution pattern ofLiberobacter asiaticumin orange forests was aggregated distribution. The spatial distribution pattern changed with the aggregation intensity and disease grade.The uniformly spatial distribution pattern indicated that the disease grade in the early stage of illness was at a low level,then raised in the aggregated distribution pattern.By analyzing,the fundamental factors of aggregated distribution ofLiberobacter asiaticumin orange forests was individual group,and the orange trees attracted each other, which mainly infected and spread by germ-carrying citrus psyllid.On the basis of inference,the aggregation intensity ofLiberobacter asiaticumstrengthened with the increase of the years of incidence orchards,and increased with the rising of disease grade[29-31].

Spatial distribution of Liberobacter asiaticum and disease spreadAnalyzed by aggregation average test, the threshold that discriminated the cause ofLiberobacter asiaticumaggregation was 2.118 4 of the average disease grade density.The relationships between average aggregation intensity and average disease grade density ofLiberobacter asiaticumwere linear correlation.When the disease grade at low density,aggregation may be caused by infection of germ-carrying scion or germ-carrying psyllid or unconspicuous diseased trees.While at high density,aggregation may be caused by the spread of infection of germ-carryingLiberobacter asiaticum,which resulted in the opportunity of re-infection increased,and the average aggregation value also became larger[32-35].

Using the mathematical model via theoretical sampling to guide disease control and monitoringEpidemic prevention and control surveyed by analyzing and establishing theoretical sampling model and determining the theoretical sampling tables[36].Contrast to the theoretical sampling tables, the epidemic general investigation rate should not less than 80%.For epidemic surveillance and investigation, referred to theoretical sampling tables, 10 plants per land were checked in high density orchards;15 plants per land were checked in medium density orchards;20 to 30 plants per land were checked in low density orchards. So the morbidity status of investigated orangery could be knew[37-38].The sequential sampling table should be used to determine the survey[39-41]as to give the prevention decision of orchards.When the accumulative disease grade of the surveyed orchards reached the set index,the investigation could be stopped.The accumulative disease grade divided the total number of samples was the average disease grade density,which had an important role in prevention and monitoring and early warning ofLiberobacter asiaticum.

Epidemic diffusion regularity and dynamic model of Liberobacter asiaticum

From 2002 to 2011,orchards controlled by three different control measures contained lose control Orangerie,general prevention Orangerie,comprehensive prevention and control Orangerie were investigated in order to study the epidemic diffusion model and the prevention and control effects[42-43]in Huangyan district.The epidemic diffusion model ofLiberobacter asiaticumin lose control Orangerie showed a linear increasing trend,the diffusion rate was fastest after the invasion of 3 to 7 years,and the annual infection rate increased 9.03%-29.85%.By statistical analysis, the relationships between annual sequence and epidemic diffusion index (disease infection rate)was extremely significant.According to this,the relationship mathematical mode established.Predicting from this mode,the epidemic diffusion rate ofLiberobacterasiaticumin the loss control Orangerie from invasion to 100%of infection rate just needed nine years,that is the annual morbidity of Liberobacter asiaticum in loss control Orangerie which was not in prevention and control status was 11.11%.The epidemic diffusion model ofLiberobacter asiaticumin general prevention Orangerie showed a rapid diffusion trend,the diffusion rate was fastest after the invasion of 3 to 6 years,and the annual infection rate increased more than 7%. By research and analysis,the relationships between the annual sequence and accumulative infection rate of theLiberobacter asiaticumwere extremely significant.From this established mathematical mode,the epidemic diffusion rate ofLiberobacter asiaticumin the general prevention Orangerie from invasion to 100%of infection rate needed no less than 18 years.The actual survey indicated that the annual infection rate was 4.69%in nearly 11 years.Compared with the infection rate ofLiberobacter asiaticumin loss control Orangerie,the average control effect maintained at 40%to 50%,and the average control effect was 43.93%.According to the data surveyed in comprehensive prevention and control area,the annual sequence and accumulative infection rate were used to test its correlations,and established mathematical mode under comprehensive prevention and control conditions.The model showed that the annual morbidity ofLiberobacter asiaticumin comprehensive prevention Orangery was 0.31%.Compared with the loss control Orangerie,the average control effect ofLiberobacter asiaticumwas 96.15%[44].Therefore,in the future prevention and control work ofLiberobacter asiaticum,theLiberobacter asiaticumcould be controlled as long as make great efforts to implement the comprehensive measures.

Comprehensive Prevention Study ofLiberobacter asiaticum

Pest and disease prevention and control effect

From 2003 to 2009,the occurrence conditions of the pest control area and the loss control Orangerie were investigated.In 2009,the accumulative infection rate ofLiberobacter asiaticumwas 58%in the pest control area,which was 99.86%in the loss control Orangerie.The control effect was 41.92%in pest control area[44].

Fitness cultivation and the reduce of incidence effect

From 2003 to 2006,the occurrence conditions ofLiberobacter asiaticumin fitness cultivation orchards and general cultivation orchards were investigated.The growth of fitness cultivation orchards was obviously stronger than the control area.And the disease incidence was significantly inferior to the control area.410 orange trees in fitness cultivation orchards were investigated,18 trees were diseased,and the morbidity was 4.3%. While 270 orange trees in the control area of the adjacent orchards were investigated,44 trees were diseased, and the morbidity jumped to 16.3%[45].Comprehensive control practices ofLiberobacter asiaticumand its effects

Since November 2002,Liberobacter asiaticumwas first discovered, the government of Huangyan district paid high attention to the epidemic prevention and control work.According to the prevention and control strategies of"pay equal attention to dig and cure and manage,comprehensive prevention and control"[46-47],"6 persist"and"5 not loss"should be done to effectively controlledLiberobacter asiaticum.The incidence had been reduced to 43 thousand in 2013 from 356 thousand in 2005.A total of 1.994 5 million diseased trees were eradicated in 11 years.The occurrence range shrunk year by year,and the incidence also decreased year by year.It means that the prevention and control work obtained actual effect[48].

Problems and Prospects

Liberobacter asiaticumwas quarantine pest in China,the citrus was a kind of perennial fruit,and its economic life span was up to 100 years.The yield of 30 years-old orange trees was up to 150-200 kg per plant.But once infected byLiberobacter asiaticum, even if cut off the infected branches, the life span of the orange trees was less than 5 years,and the life span of orchards was less than 10 years[49]. The pathogenetic fruits had no edible value,so farmers suffered heavy losses.Today’s technology could not solve the problem ofLiberobacter asiaticum,the measures were only cut and dig trees.From 10 years of practice for the occurrence regularity research and prevention and control work ofLiberobacter asiaticum,as long as government leadership and orange farmers did teamwork actively, remould the heavy pathogenetic orchards,planted virus-free seedlings, adopted comprehensive prevention and control measures,grasped the prevention and control work in the critical period,eradicated the primary infection trees,Liberobacter asiaticumwas preventable and controllable.Of course,with the help of modern molecular biology techniques to study the interaction mechanism of citrus themselves andLiberobacter asiaticum,searched the anti-diseaseresistant gene[50],cultivated and screened resistant varieties,or transferred resistance gene to an existing highquality varieties without changing the quality,which made the citrus do not morbidity or show symptoms,maybe could fundamentally solve the problem of prevention and control ofLiberobacter asiaticum.

In addition,if made a breakthrough at isolated culture of pathogens and treatment technology, not adopted cut and dig measures to solve pathogenetic or infectious citrus, but took chemotherapy treatment to make citrus recover healthy gradually. In this way,cut and dig rate of diseased trees would reduce greatly and the costs of prevention and control work would significantly reduced.For this reason,the recent researches of treatment technology ofLiberobacter asiaticumattempted to adopt biologic agents such as deguelin,flavonoids and terpenoids.The achieved initial results indicated that the action principle of such agents had relatively strong absorption and penetration,which could penetrate to the interior of vascular tissue of citrus and killedLiberobacter asiaticum.Meanwhile,it could softened the impurities in the screen wall,dredged guide screen pipe,andensured normal transport of water,nutrient and leaf photosynthesis products.In the top of graft union of citrus stem base,with a diameter of 3.5-4.0 mm drill bit and angled 30°-35°,cross drilling 3 to 4 holes with the depth of 2-4 cm according to the size of citrus to make the drug liquid evenly inject into the tree body.And then used a kind of fruiter drug liquid injection device[51]. The prepared bactericide and dredge agents were injected into diseased trees in vivo with high-pressure method,which not only killed infected pathogens in the trees body,but also dredged transport corridors blocked by pathogens,and made nutrients and water of citrus transport unblocked, restored growth function of sick citrus, reached therapeutic purposes ofLiberobacter asiaticum.By means of modern molecular biology to find resistance genes,cultivating and screening resistant varieties and taking medication technology will help to finally solveLiberobacter asiaticum, which perhaps the ultimate goal that scientists do the study ofLiberobacter asiaticum.

[1]DI DZ(狄德忠).Taizhou citrus historic textual research(台州柑橘史考)[J]. Zhejiang Citrus(浙江柑橘),1985(3): 41-42.

[2]WANG HZ(王恒正).The history,current situation,problems and countermeasures of tangerine in Huangyan(黄岩蜜橘历史现状问题及对策浅析)[J].Zhejiang Citrus(浙江柑橘),2001,18(1):5-7.

[3]XU JG(徐建国).Origin discussion of Bendizao tangerine(本地早蜜橘起源的考析)[J].Zhejiang Citrus(浙江柑橘), 2005,22(3):2-6.

[4]WANG LX(王领香),GONG JQ(龚洁强), WANG LH(王立宏).Textual research on the varieties,origins and history of Bendizao(关于本地早品种起源与历史的考证)[J].News of Citrus and Subtropical Fruit(柑橘与亚热带果树信息), 1999(5):6-7.

[5]LIN YB(林云彪),YU JH(余继华),MENG YQ(孟幼青).Liberobacter asiaticumand sustainable management(柑橘黄龙病及其持续治理)[M].Beijing:China Agricultural Science and Technology Press(北京:中国农业科学技术出版社), 2012:7-41.

[6]YU JH(余继华),WANG EG(汪恩国). Research of invasion and epidemic spread model ofLiberobacter asiaticum(柑橘黄龙病入侵与疫情扩散模型研究) [J].Chinese Agricultural Science Bulletin(中国农学通报),2008(8):387-391.

[7]Research group for monitoring and preventing and controlling strategy ofLiberobacter asiaticumin Huangyan district(黄岩区柑橘黄龙病监测与防控对策研究课题组).Research techniques summary of monitoring and preventing and controlling strategy ofLiberobacter asiaticum(柑橘黄龙病监测与防控对策研究技术总结)[R].2006:24-25.

[8]TEIXEIRA D C,SAILLARD C,COUTURE C,et al.Distribution and quantification of CandidatusLiberibacter americanus,agent of huanglongbing disease of citrus in Paulo State,Brazil,in leaves of an affected sweet orange tree as determined by PCR[J].Molecular and Cellular Probes,2008,22:139-150.

[9]YU JH(余继华),WANG EG(汪恩国), ZHANG MR(张敏荣),et al.The relationships between precociousLiberibacter americanusprevalence and yield loss(早熟柑橘黄龙病流行与所致产量损失关系研究)[J].Plant Protection(植物保护),2011,37(4):126-129.

[10]TIAN YN(田亚南),HE S(柯穗),LI T(李韬),et al.The Application of electron microscopy and PCR technology to detected pathogens ofLiberibacter americanusof Gongxi honey pummelo (应用电镜与PCR技术检测宫溪蜜柚黄龙病病原)[J].Acta Phytopathologica Sinica(植物病理学报),2000,30(1): 76-81.

[11]HUNG T H,HUNG S C,CHEN C N,et al.Detectioin by PCR of CandidatusLiberibacter asiaticus,the bacterium causing citrus huanglongbing in vector psyllids:application to the study of vector-pathogen relationships[J].Plant Pathology,2004,53:96-102.

[12]DING F,JIN S X,HONG N,et al.Vitrification¨Ccryopreservation,an efficient method for eliminatingCandidatus Liberobacter asiaticus,the citrus Huanglongbing pathogen,from in vitro adult shoot tips[J].Plant Cell Reports, 2008,27:241-250.

[13]YE ZY(叶志勇),YU JH(余继华), WANG EG(汪恩国),et al.Research of population spatial distribution pattern and sampling technique of citrus psyllid(柑橘木虱种群空间分布型及抽样技术研究)[J].China Plant Protection(中国植保导刊),2007,27(6):35-37.

[14]YE ZY(叶志勇),YU YM(於一敏),YU JH(余继华).The occurrence and integrated control technology of citrus psyllid(柑橘木虱的发生及综合防治技术)[J].Zhejiang Citrus(浙江柑橘), 2006(9):28-29.

[15]ROISTACHER C N.Techniques for biological detection of specific citrus graft transmissible diseases[J].FAO, Rome,1991(286):35-45.

[16]QIU LF(仇兰芬).Important pest of fruit trees(危害果树的重要害虫)[D].Beijing:Chinese Academy of Forestry(北京:中国林业科学研究院),2008:21.

[17]LAN XP(兰星平).The Application of regression model groups of population aggregation index in the test of insect population spatial distribution pattern (种群聚集度指标回归模型群在检验昆虫种群空间分布型中的应用)[J]. Guizhou Forestry Science and Technology(贵州林业科技).1995(3):8-10.

[18]GOTTWALD T R,AUBERT B,HUANG K L.Spatial pattern anslysis of citrus greening in Shantou,China[C]. Proceeding of 11thConference of the International Oraganization of Citrus Virolagists,Reiverside,CA,1991: 421-427.

[19]Liberibacter americanusresearch group of Guangxi province(广西柑橘黄龙病研究小组).Summary of the investigation and review of Liberibacter americanus in Guangxi in 1964(1964年广西柑橘黄龙病调查复查总结)[R]. 1965 internal data(内部资料).

[20]WANG BY(王本洋),YU SX(余世孝). Multi-scale analysis of population distribution pattern(种群分布格局的多尺度分析)[J].Chinese Journal of Plant Ecology(植物生态学报),2005,29(2): 235-241.

[21]WANG HF(王会福),WANG EG(汪恩国),CHEN WQ(陈伟强).Spatial distribution pattern and sampling techniques of brown planthopper in single cropping rice(单季稻褐飞虱空间分布格局及其抽样技术)[J].Chinese Agricultural Science Bulletin(中国农学通报),2010(12):270-273.

[22]Ministry of Agriculture citrus and seedlings Quality Supervision and Testing Center,Citrus Research Institute of Chinese Academy of Agricultural Sciences,Sichuan Agriculture Department Plant Quarantine Station.NY/ T973—2006,Citrus virus-free seedling breeding regulations(农业部柑橘及苗木质量监督检验测试中心,中国农业科学院柑橘研究所,四川省农业厅植物检疫站.NY/T973—2006,柑橘无病毒苗木繁育规程)[S].Beijing:China Agriculture Press(北京:中国农业出版社), 2006:31.

[23]QIU ZS(邱柱石).Talk about the field diagnosis ofLiberibacter americanus(谈谈柑橘黄龙病树的田间诊断)[J]. Guangxi Horticulture(广西园艺),1995 (1):21-22.

[24]ZHAO XY(赵学源),JIANG YH(蒋元晖),LI SL(李世菱),et al.Preliminary study of the relationships between citrus psyllid andLiberibacter americanus(柑橘木虱与柑橘黄龙病流行关系的初步研究)[J].Acta Phytopathologica Sinica(植物病理学报),1979,9 (2):121-126.

[25]XU CP(许长藩),XIA YF(夏雨华),KE C (柯冲).Research of biological characteristics and control of citrus psyllid(柑橘木虱生物学特性及防治研究)[J].Acta Phytophylacica Sinica(植物保护学报),1994,21(1):53-56.

[26]WU RJ(吴如健),KE C(柯冲).Control test and integrated control measures ofLiberibacter americanus(柑橘黄龙病治理试验及综合防治措施)[J].Acta Agriculturae Jiangxi(江西农业学报), 2007,19(9):69-71.

[27]HE DF(何大富).Chinese Citrus(中国柑橘学)[M].Beijing:China Agriculture Press(北京:中国农业出版社),1999: 578-579.

[28]YU JH(余继华),WANG EG(汪恩国). Hazard and control index ofLiberibacter americanus(柑橘黄龙病发生危害与防治指标研究)[J].Acta Agriculturae Zhejiangensis(浙江农业学报),2009,21 (4):370-374.

[29]LOU BH(娄兵海).Preliminary study ofLiberibacter americanuspathogens and intraspecific differentiation in eight provinces of China(中国八省柑橘黄龙病病原菌种类和种内分化的初步研究) [D].Chongqing:Plant Protection, Southwest University(重庆:西南大学植物保护学院),2008:7-8.

[30]XU RM(徐汝梅),LIU LF(刘来福),DING YQ(丁岩钦).Improved IwaoM*-M model(改进的IwaoM*-M模型)[J]. Acta Ecologica Sinica(生态学报),1984 (2):111-117.

[31]ZHONG C(钟琛),LI J(李健),SHI Q(施清),et al.Research of Hazard and epidemic regularity ofLiberibacter americanusin Fujian Province(福建省柑橘黄龙病危害及其流行规律研究)[J]. Scientia Agricultura Sinica(中国农业科学),2009,42(11):3888-3897.

[32]MA ZS(马占山).Further explanation of power law and population aggregates critical density(幂法则的进一步解释与种群聚集临界密度)[M].Beijing:China Science and Technology Press(北京:中国科学技术出版社),1991:284-288. [33]WANG Z,YIN Y,HU H,et al.Development and application of molecularbased diagnosis for‘Candidatus Liberibacter asiaticus’,the causal pathogen of citrus huanglongbing[J]. Plant Pathology,2006,55:630-638.

[34]YANG YB(杨余兵).The influence of light,temperature and humidity on the development,reproduction and survival of citrus psyllid(光温湿度对柑橘木虱发育、繁殖与存活的影响)[J].Acta Ecologica Sinica(生态学报),1989,9 (4):348-354.

[35]WANG XF(王雪峰).Research of genetic diversity and population differentiation ofLiberibacter americanuspathogen based on genome multiplesite comparison(基于基因组多位点比对的柑橘黄龙病病原菌遗传多态性及种群分化研究)[D].Chongqing:Plant Protection,Southwest University(重庆:西南大学植物保护学院),2011:21-22.

[36]CHEN TH(陈庭华),CHEN CX(陈彩霞). Occurrence regularity and new forecasting methods of prodenia litura(斜纹夜蛾发生规律和预测预报新方法)[J]. Chinese Bulletin of Entomology(昆虫知识),2001(1):36-39.

[37]YU JH(余继华),WANG EG(汪恩国), ZHAO L(赵琳).Research of spatial distribution pattern and sampling technique ofLiberibacter americanus(柑橘黄龙病空间分布型与抽样技术研究)[J]. Plant Quarantine(植物检疫),2010,24 (5):31-34.

[38]ZENG W(曾伟).Preliminary study of the spatial distribution and sampling technique of Spodoptera exigua in bunching onion fields(分葱田甜菜夜蛾空间分布型及抽样技术初步研究)[J]. Plant Protection Technology and Extension(植保技术与推广),2003,23(8): 11-12.

[39]ZHEN YM(郑永敏).Application of the spatial distribution and sequential sampling technique of rice sheath blight(水稻纹枯病的空间分布型及序贯抽样技术的应用)[J].Journal of Zhejiang Agricultural Sciences(浙江农业科学), 2000(5):236-238.

[40]HUA F(华放).Common mathematical analysis methods of insect ecology(昆虫生态学的常用数学分析方法)[J]. Science Bulletin(科学通报),1964(4): 375-376.

[41]ZHOU TG(周桃庚),SHA DG(沙定国). Bayesian reliability sequential demonstration test method(贝叶斯可靠性序贯验证试验方法)[J].Chinese Journal of Scientific Instrument(仪器仪表学报),2001(1):23-25.

[42]YU JH(余继华),WANG EG(汪恩国). Research of invasion and epidemic diffusion model ofLiberibacter americanus(柑橘黄龙病入侵与疫情扩散模型研究)[J].Chinese Agricultural Science Bulletin(中国农学通报),2008,24 (8):387-391.

[43]XU YM(徐艳梅),LI F(李菲),et al.Pandemic virus propagation model and technology innovation diffusion analysis(流行病毒传播模型与技术创新扩散分析)[J].Chinese high-tech enterprises(中国高新技术企业),2008(2):38-39.

[44]YU JH(余继华),WANG EG(汪恩国), LU L(卢璐),et al.Research of epidemic evolvement rule and prevention effect ofLiberibacter americanusunder different management style(柑橘黄龙病不同管理方式疫情演变规律及防控效果研究)[J].Journal of Agriculture (农学学报),2013,3(4):9-12.

[45]ZHANG MR(张敏荣),YU JH(余继华), YU YM(於一敏),et al.Fitness cultivation measures could be taken to reduce the occurrence ofLiberibacter americanus(采取健身栽培措施可以减轻柑橘黄龙病发生)[J].Zhejiang Citrus (浙江柑橘),2007(4):28-30.

[46]ZHO PZ(赵沛忠),LEI SY(雷沈英),DU YX(杜一新),et al.Prevention and control working practice ofLiberibacter americanusin Jingning county(景宁县柑橘黄龙病防控工作实践)[J].Plant Quarantine(植物检疫),2010(4):63-65.

[47]DU YX(杜一新),LIN YB(林云彪). Thoughts on prevention and control measures ofLiberibacter americanus(对柑橘黄龙病防控工作措施的思考) [J].Plant Quarantine(植物检疫),2006 (4):257-258.

[48]TAO J(陶健),YU JH(余继华),ZHANG MR(张敏荣).Practice and experience of the prevention and control work ofLiberibacter americanus(黄岩柑橘黄龙病防控工作的实践与体会)[J].Zhejiang Citrus(浙江柑橘),2011(1):27-28.

[49]DUAN XJ(段小军).Citrus aging prevention(柑橘老化的防治)[J].Hunan Forestry(湖南林业),2005(9):25.

[50]LI YM(李云明),GU YQ(顾云琴),XIANG SY(项顺尧),et al.Discussion of occurrence characteristics and prevention and control measures ofLiberibacter americanus(柑橘黄龙病的发生特点及防控对策探讨)[J].Modern Agricultural Science and Technology (现代农业科技),2007(11):64-65.

[51]YU JH(余继华).One kind of fruit agent injection device(一种果树药剂注入装置)[P].Chinese Patent(中国专利), 201320497901.7,2014-02-05.

Responsible editor:Lin FANG

Responsible proofreader:Xiaoyan WU

台州柑橘黄龙病防控研究新进展

余继华1，张敏荣1*，陶健1，卢璐1，杨晓1，汪恩国2，叶志勇3
（1.浙江省台州市黄岩区植物检疫站，浙江黄岩318020；2.浙江省临海市植物保护站，浙江临海317000；3.浙江省台州市黄岩区农业局，浙江黄岩318020）

根据十几年对柑橘木虱和柑橘黄龙病发生规律与防控技术研究探讨，明确了柑橘木虱在台州橘林的发生分布规律和抽样技术，分析了柑橘木虱虫株率和带毒率与黄龙病、黄龙病与柑橘产量损失等之间的关系，探讨了柑橘黄龙病预警和柑橘木虱防治指标，建立了不同管理方式下的疫情扩散模型预测橘林经济寿命，提出了柑橘黄龙病综合防控技术和可防可控的理念。

柑橘黄龙病；柑橘木虱；发生规律；扩散模型；控制指标；防控技术

农业部公益性行业（农业）科研专项经费项目“柑橘黄龙病和溃疡病综合防控技术研究与示范”（201003067）；浙江省科技计划项目“柑橘黄龙病监测与防控策略研究”（2004C32087）。

余继华（1960-），男，浙江台州人，高级农艺师，硕士，从事植物检疫与防控技术研究。*通讯作者，E-mail：yo5428@zjip.com。

2015-03-08

修回日期 2015-05-10

Supported by the Ministry of Agriculture and public service sectors(agriculture) Research and Special Project Funds‘Comprehensive Prevention and Control Technology Research and Demonstration of Liberibacter americanu s and Canker’(201003067);Science and Technology Planning Project of Zhejiang Province‘Research of Surveillance and Control Strategy of Liberibacter americanus’(2004C32087).

*Corresponding author.E-mail:yo5428@zjip.com

Received:March 8,2015 Accepted:May 10,2015