(Pictures are thumbnailed below, Please click to enlarge pictures of phytoplasma infected plants)
Healthy ash tree (left) and ash yellows (AshY) diseased ash tree (right, center, and bottom). Arrows indicate
close-up views of witches' broom
symptoms caused by ash yellows phytoplasma ('Candidatus Phytoplasma fraxini').
Left: grapevine yellows (GY) disease in Sicily, Italy; symptoms include yellowing of veins in leaves and necrosis of fruit. Right:
grapevine yellows disease (VGY) in Virginia; symptoms include curling of leaves.
Cabernet-Sauvignon grapevine plant showing symptoms of grapevine yellows disease in Virginia. Phytoplasma DNA was detected in the veins of leaves with symptoms. Photo by R.E. Davis, August 2010.
Chardonnay grapevine plant showing symptoms of grapevine yellows disease in Virginia. Phytoplasma DNA was detected in the veins of leaves with symptoms. Photo by R.E. Davis, August 2010.
Healthy coconut (left) and coconut suffering from lethal yellowing (LY) disease (right)
in Ft. Lauderdale, Florida, USA. Symptoms include
yellowing and death of leaves. Coconut trees are killed by this disease.
The spread of coconut lethal yellowing disease has been retarded by treatment of trees with a
tetracycline antibiotic in Florida. The trunk of this tree shows locations where the antibiotic was
injected.
Chokecherry infected by peach X-disease phytoplasma in
Connecticut, USA. Symptoms include premature fall coloration of leaves.
Healthy sweet potato (left) and sweet potato little leaf disease (right) in
Taiwan. Symptoms include reduced size of leaves and stunting of the diseased plant.
Dandelion phyllody disease in Udine, Italy. Arrows
indicate symptoms of phyllody in flowers (left). Healthy plant is on the right.
Malaysian periwinkle yellows disease in Madagascar periwinkle (Catharanthus roseus) (right). Note severe yellowing of
lower
leaves, below which are normal green leaves. Plant also exhibits flower abnormalities of virescence and phyllody.
Red clover photographed in the field in Italy (right). Diseased
flowers
on left exhibit phyllody symptoms. Normal flower is on the right.
Symptoms induced in a diseased plant of Catharanthus roseus (Madagascar periwinkle) by peanut witches' broom
phytoplasma. Peanut witches' broom phytoplasma is a member of phytoplasma 16S rDNA RFLP group 16SrII. Note symptoms
of big bud, phyllody, and virescence of flowers.
Notes: Latin names of plants -- Latin names of the plants should be in italic
letters.
'Candidatus' names -- 'Candidatus phytoplasma
asteris' should be written as 'Candidatus Phytoplasma
asteris'. The correct abbreviation is 'Ca. Phytoplasma
asteris'.
For more about Grapevine Yellows,
