DISEASES OF THE COTTON PLANT. ITT 
likewise been said that an insect similar, if not identical 
with the grass-caterpillar, destroys the leaves of the sweet 
potato. Thus it appears to he almost omnivorous, and 
not choice in its selection of food, like the true cotton 
caterpillar, which is believed to confine itself to the cotton 
plant alone. 
The grass-worm cannot be classed among those insects 
very injurious to cotton, although instances have been 
known where it has destroyed the foliage to some extent. 
It is more especially mentioned here as being found in 
cotton fields, and often confounded with the true cotton 
caterpillar. The difference, however, is more plainly de- 
scribed under the head of the latter. 
The same remedies are applicable to this insect as have 
been suggested for the boll-worm caterpillar, or any other 
night-flying moth. 
The Red Spider. — (Acarus?) 
Much injury is done to the cotton leaf by a minute red 
spider, which presents very much the appearance of in- 
cipient rust, except that the leaf is of a more rusty brown 
in spots, instead of the bright yellow of the real rust. This 
red spider principally attacks the under side of the leaf, the 
spots caused by its punctures turning brown, and finally in- 
creasing until it is completely stung all over, and falls from 
the plant. 
This insect is extremely minute, and when on the leaf 
it can scarcely be discerned by the naked eye. Some of 
the young appear to be of a greenish cast ; but when they 
are advanced in age the abdomen assumes a dark crimson 
shade, with darker maroon spots upon its upper surface. 
The legs, which are hairy, are eight in number. 
This family of the mites {Acari) do much injury to 
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