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grown corn, whose vigor was plainly impaired by it. , 
_ The injury consists (1) in loss of food materials elaborated by the ' 
plant for its own growth, which the threads (mycelium) of the fun- 
gus, ramifying in the tissues of the corn, absorb for their growth 
and the formation of spores; (2) in destroying the power of some of 
the tissues to do their work, and of the chlorophyll contained in them 
' to continue the elaboration of fresh food supplies for the corn. 
When coming early in the season the rust is likely to be more than 
usually injurious later in the same year, and to continue so the year 
following. 
‘Thus far the experiments made in combating the rusts have yielded | 
ho positive results. 
16.—ERINOSE. 
Phytoptus vitis, 
(Plate XVII.) 
(@) GENERAL OBSERVATIONS, 
The name Hrinose is here adopted to designate a special disease of 
the leaves of the grape-vine caused by a minute acarid, the Phytop- 
tus vitis, Formerly the peculiar effects produced by this Phytoptus, 
as well as those caused by other species which infest the alder, 
maple, beech, etc,, were thought to be fungi, and were all included 
by the older mycologists in the genus Hrineum. In the case of the 
vine, the effect produced by this little animal parasite bears a strong 
resemblance to the external appearance of the downy mildew, and 
samples have been sent to us from various parts of the country under — 
the supposition that the leaves were infested with the Peronospora. 
As it is very important to be able to distinguish the one, which is 
’ always to be dreaded, from the other which rarely if ever does any 
serious injury, the peculiar characters of Krinose will be here pointed ,. 
out. 
{ 
(6) EXTERNAL APPEARANCE. 
EKrinose usually appears in early summer in the form of raised, | 
lustrous white spots on the lower surface of the leaves. The color 
soon becomes yellow, and finally a dark reddish-brown. The spots, 
usually small and scattered irregularly over the surface between the 
nerves, are sometimes of considerable size, and we have occasionally 
‘found leaves of Vitis estivalis with their lower surfaces entirely 
covered by Erinose. There is no evidence of the disease on the 
upper surface of the affected leaves in the wild or cultivated vines 
of the Eastern and Middle States, If attacked while young they 
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