INCORRECT DIAGNOSIS OF THE POTATO
PURPLE TOP
Ing. Josi Garcma de la Rosa
jgarciadelarosa@
prodigy.net.mx
Before 1967, many plant diseases were erroneously diagnosed as "virus", due
to ignorance of the existence of phytoplasmas that were discovered that year
by Doi et al in Japan. Besides, in the case of the potato purple top was
reported as a micro nutrients deficiency and, occasionally, as a symptom of
Phytophthora infestans or Fusarium.
Remission of symptoms in potato with purple top, after several
oxytetracyclin applications, 1987, Toluca Valley.
Remission of "rayado fino" symptoms in corn after the antibiotic
application.
A few years later, potato purple top was proven to be caused by phytoplasma
following the steps of the scientific method, the fulfillment of Koch
Postulates, and the remission of symptoms when oxytetracyclin was applied.
Psyllids and leafhoppers were proven to be insect vectors of this disease.
Remission of symptoms in pawpaw, with symptoms of "virus disease" in the
lower leaves. 2002, Cuautla, Morelos. Mixico.
