THE ROOT-KNOT. 
DEFINITION. 
An abnormal and irregular growth of the subcortical layer of roots 
and subterranean stems, characterized by low vitality, the result of 
an invasion of the tissues by a Nematode worm. (Note 1.) 
HISTORY. 
Since the earliest settlement of the South Atlantic and Gulf States 
by white people this diseased condition of the roots of trees and plants 
lias been recognized. (Note ( 2.) 
A very slight inspection 1ms shown the decaying enlargements of 
roots, but the cause has usually been attributed to a lack in the soil of 
some important fertilizing ingredient, or careless cultivation, rather than 
some potent exterior influence. 
I have carefully examined all sources of information at my command, 
and can find no mention of the root-knot in any agricultural paper or 
book prior to the year 1857. 
That year Hon. P. J. Berckmans established a nursery at Augusta, 
Ga., and soon found this disease prevalent in many varieties of trees 
and plants, and in 188L Prof. 0. V. Riley being at Augusta was shown 
the effect of the disease by Mr. Berckmans. 
In 18G9 Mr. Gilbert Onderdonk, of Nursery, Tex., noted the disease 
in his fig, grape, and peach stocks, especially in damp, undrained loca- 
tions. 
In 187G I found the root-knot prevalent over Florida, and learned from 
old residents that as far back as 1805 it had been known, and from time 
immemorial had been dreaded as a foe to gardens and groves. 
About 1874 this disease, however, sprang into prominence, owing to 
the influx of immigrants, the development of early-market gardens and 
the sudden rage for orchards of peaches, figs, and oranges. 
Since that time the agricultural papers have contained numerous ref- 
erences to this disease. My own attention was called to this pest by 
repeated failures to grow certain plants in a rich, damp spot on my 
farm. 
This led me to investigate; and sending a specimen of the knotty 
roots to the Agricultural Department at Washington, elicited the infor- 
mation that a .microscopic worm was the cause of the trouble, but that 
little was known of the Nematoid family to which it belonged. 
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