Diagnosis And Control Of Citrus Nematode Disease In Fujian, China

In recent years, the citrus industry was declined gradually in Fujian province.According to previous surveys, the key factor of abandoning farmlands by orchardistswas the yellowing plants were diagnosed as Citrus Huanglongbing generally. Thisarticle investigated the Citrus Huanglongbing and nematode diseases in some of themajor citrus production areas in Fujian province from2009to2012, and from whichwe found one of the main reasons to the citrus yellowing occurring in large area inFujian province was citrus nematode diseases. This survey proposed a diagnostictechnique for citrus yellowing and decline disease through symptom, molecular testsand morphological identification,12kinds of parasitic nematodes were identified ininvolved areas.According to a systematical study of important nematodes, Tylenchulussemipenetrans，Pratylenchus coffeae and Pratylenchus zeae, we proposed a diagnosedskill of Slow decline of Citrus and Citrus slump disease through symptom recognition,morphological of pathogen and molecular biological identification. This surveyoptimized nematode sample preparation techniques for electron microscope byUNIQ-10column. And also the morphology characters of the two species and theirinfection status on the root were observed and described by Lactic acid glycerindyeing method as well as the scanning electron microscope interiorly. The influencethat carrot callus exerts upon the morphology characters of P. zeae were discoveredand discussed.The528SrDNA-D3/D3sequences of T. semipenetrans and628SrDNA-D3/D3sequences of Pratylenchus from Fujian zhangzhou and nanping city were sequenced,blasted and analyzed. The result shows that the28SrDNA-D3/D3sequences in both T.semipenetrans and P. coffeae were very conservative with minimum differences,and the similarity were more than99%.The phylogenetic trees of differentgeographical population of T. semipenetrans and P. coffeae were build according tothe28SrDNA-D3/D3sequences, and from which we found that there were norelationship between genetic differences and geographical position on T. semipenetrans, but different hosts may deepen the genetic differences on P. coffeae.We studied the effect of using Paecilomyces lilacinus and Sebufos alone, themixture of P. lilacinus and Sebufos in plot experiments. And we compared thestrengths and weaknesses of these three methods through recovery degree of growth,the transformation of nematode population structure and quantity, the transformationof secondary microbial population structure and separating percentage between thecontrol before and after. According to these analysis, the mixture of P. lilacinus andSebufos was considered as effect drugs, which will propose theoretical basis for thestudying about T. semipenetrans in the future and play an important role in thediagnosis and control work of nematode diseases in Citrus yield in Fujian province.