isolate and identify the agent of maize disease detected in 
field experiments in 1970-1971 in large maize cultivations 
and in maize of different kinds in the Ukraine. 
The identification of the agents of the disease in 
laboratory was being done on specimen of sick plants which 
showed the symptoms one most frequently encounters in the 
field (mosaicness of the leaves). The agent is easily 
transferred to healthy plants by means of mechanic inocula- 
tion of the sap of sick plants. The symptoms of the disease 
caused by artificial infection were similar to the ones 
observed in field experiments. 
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Figur égsad 
Leaf of healthy maize 
On being infected in the phase of 3 to 5 leaves by 
rubbing the leaves with the infected sap the maize showed 
bright irregular spots appearing onthe mainly young leaves 
5 to 18 days after the infection and extending to the blade. 
After they grew bigger they merged along the leaf vein in 
strips (figure 2a) and lines of yellow color (figure 2b). 
As a result of these symptoms spreading over the whole leaf 
blade chlorotic sections formed scattering on the green 
background of the leaf and, in the later stage of disease, 
the symptoms appeared in the form of green dots and strips 
against the chlorotic background (figure 2c). The symptoms 
(2) 
