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Huanglongbing (HLB), previously known as citrus greening disease, is one of the most destructive diseases of citrus and responsible for the decline of citrus orchards in Andhra Pradesh (AP) and other citrus growing areas in the country. Polymerase chain reaction (PCR) amplification of 1160 bp fragment of 16S rDNA of HLB was observed in mottling symptoms, yellow vein symptoms, symptoms mixed with both citrus yellow mosaic virus and citrus greening and zinc deficiency-like symptoms; however, no amplification was observed in iron deficiency like symptoms. As the disease shows a variety of symptoms in infected trees, PCR detection could be useful for resolving confusion in identification of HLB between actual deficiency and deficiency like symptoms caused by HLB. In acid lime the midrib and veins of the leaves with both mottling and yellow vein symptoms were suitable for isolation of DNA and used as a template in the PCR test. [ABSTRACT FROM AUTHOR]

Citrus yellow mosaic virus (CYMV) was detected by polymerase chain reaction (PCR) in leaf samples of sweet orange, Rangpurlime, Pumello pink and acid lime and also in twig bark, fruit rind, fruit juice except fruit rag of sweet orange cv. Sathgudi, where all the positive samples showed bright amplification of the 726 bp band except in fruit rind. The CYMV could be detected by the biotin labelled probe of CYMV up to 1:100 dilutions by TE and TNE extraction methods in sweet orange cv. Sathgudi as well as Rangpurlime. [ABSTRACT FROM AUTHOR]