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For Hemiptera-Phytoplasma interaction three categories were defined according to the available evidence about the capability of the insect to transmit the pathogen, as follows:
1. Vectorial Competence. A hemipteran species is considered a COMPETENT VECTOR for a certain phytoplasma if the capability of the latter to overcome the barriers of gut and salivary glands of the insect has been proven using classical acquisition/inoculation experiments in the laboratory or inoculation trials with caged infected specimens collected from the field. Moreover, the successful transmission of the phytoplasma to the plant has been detected on tested insects and plants using Polymerase Chain Reaction (PCR) targeting the 16S–23S rRNA genes, observed or virtual RFLP fingerprinting, or DNA sequencing methodsCLICK HERE, in addition to detection of clear symptoms due to phytoplasma presence in the plant. A less strict evaluation may be applied for papers published before the PCR molecular era (before 1980s), especially if the same insect species were later demonstrated to be competent vectors in the same region.
2. Positive Detection in insect. A hemipteran is considered a POTENTIAL VECTOR if the phytoplasma has been detected in its body using standard molecular methods. Status as a potential vector does not imply the ability to transmit the phytoplasma from plant to plant. Such insects represent dead-end hosts for the phytoplasma if it is later shown that they are not competent as vectors.
3. Negative Detection in insect. A hemipteran is considered a POTENTIAL NON-VECTOR if it tested negative for the presence of phytoplasma. The more times specimens of a species have tested negative, the more likely the species is a non-vector.
For Plant-Phytoplasma interaction two categories were defined according to the available evidence on detection of phytoplasma in the plant phloem, as follows:
4. Positive Detection in plant. A plant is considered INFECTED BY phytoplasma if the pathogen has been successfully detected in its tissues using standard molecular methods.
5. Negative Detection in plant. A plant is considered a POTENTIAL UNSUITABLE HOST if it tested negative for the presence of phytoplasma. The more times samples of a species have tested negative the more likely that species is an unsuitable host for the phytoplasma.
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