6 State Crop Pest COMMISSION OF 
NEMATODE Root Knot. 
These knots are not caused by real insects, but by little 
worms belonging to another group of animals. They sometimes 
co quite a little damage on roots of plants, causing numerous 
wart-like swellings or galls. When these animals are found in 
a nursery, the nurserymen are to destroy all trees found infested 
with this parasite when the trees are being dug. 
CoTTONY CUSHION SCALE. 
The cottony cushion scale is another one of the scale insect 
family, but, fortunately, one which we have not yet with us. 
It is known in the United States in California and Florida. This 
insect is to citrus trees what the San Jose scale is to deciduous 
trees. It is a much larger insect than the San Jose scale, white, 
and with the wax arranged in a peculiar fluted manner, suggest- 
ing the common name of fiuted scale. As in the case of the 
San Jose scale, it is a foreign insect, and the point of introduc- 
tion into this country was California. About 1868 or 1869 is 
believed to be the date of its introduction. It soon attracted 
widespread attention and for a while it was thought that the 
culture of oranges and lemons in California would have to be 
forsaken. However, in 1888, Mr. Alfred Koebele, an entomolo- 
gist, was sent to Australia to study the natural enemies of this 
insect, as in its own home it seemed to be held in check by some 
natural enemy. Fortunately for California, and probably for 
the rest of the orange-growing states as well, Mr. Koebele suc- 
ceeded in finding the insect which kept the cottony cushion scale 
from being injurious to any large extent in Australia. This 
insect was a little ladybird beetle predaceous on the cottony 
cushion scale. Mr. Koebele succeeded in importing a goodly 
number of these beetles to California, and in a few years the 
danger from the cottony cushion or fluted scale had been done 
away with. The scale afterwards got into Florida, and was dealt 
with in the same way. It still exists in both states, but whenever 
it becomes markedly injurious in a locality, the introduction of a 
few of these ladybirds soon brings it under control. 
