Grape

The main vector for this pathogen, Scaphoideus titanus is native to North America. Dictyophara europaea , another potential vector, has been intercepted at U.S. ports of entry.

Follow instructions in Phytoplasma Sample Screening and Confirmation

If you have taken the hands-on phytoplasma specific training at S&T Beltsville lab, you can screen your own phytoplasma samples. Note: You will still have to follow the protocol in the linked document for confirmations.

No specific signs are present.

Grapevine: Leaves turn yellow or red depending on the cultivar. They roll downward and become brittle. The interveinal areas of leaves may become necrotic. Shoots show incomplete lignification, and rows of black pustules develop on the green bark along the diseased branches; they are thin, rubbery, and hang pendulously. During winter they blacken and die. The inflorescences dry out and fall off. Fruit setting is reduced. In later infections, bunches are irregular and berries become shriveled. They have a significantly lower sugar content and higher acidity compared to healthy grapes.

In Clematis vitalba, a potential host, symptoms may include discoloration and wilting of leaves, although the relationship between the presence of phytoplasma and leaf symptoms is not clear.

See INRA (2013) and the CPHST Pest Datasheet for more information on the symptoms and biology/ecology of the disease.

Follow instructions in Phytoplasma Sample Screening and Confirmation

If you have taken the hands-on phytoplasma specific training at S&T Beltsville lab, you can screen your own phytoplasma samples. Note: You will still have to follow the protocol in the linked document for confirmations.

Other grapevine yellows diseases

Potentially infected samples can be analyzed for the presence of FD with a real-time PCR procedure as described in Hren et al. (2007). Further molecular characterization may than performed on the positive samples by PCR with FD9R1/FD9F1 primers followed by nested PCR with FD9F3b/ FD9R2 primers and RFLP (Mehle et al., 2011).

The primary host is Vitis vinifera. This species can also potentially infect Vitis spp, Clematis spp., and Alnus spp."Candidatus Phytoplasma vitis" is an informally proposed name.