INSECT ENEMIES AND-THEIR CONTROL 123 
into a house without being observed until considerable 
damage has been caused. When plants are transferred 
from frames or other houses they should be in inspected 
with extreme care, and if even a few white flies are found 
the plants should be fumigated before they are set in the 
permanent beds. Special boxes or small beds may be 
employed for this purpose, where hydrocyanic gas may 
be used with safety. Fumigation with this gas is recog- 
nized as the most effective means of controlling the white 
fly on tomatoes and cucumbers. See Page 109 for di- 
rections. 
Nicotine solutions are applied to some extent to kill 
the white fly. These sprays are not effective unless they 
come in contact with the insects. The same may be said 
of various soap solutions. Fumigation involves much less 
labor and it is not so expensive as spraying, whatever 
may be the character of the solution. 
Red spider (Tetranychus telarius, Linn.) is a common 
pest of the greenhouse cucumber and tomato, and it also 
feeds on the melon, bean, eggplant and many ornamental 
plants which are grown under glass. If unchecked in its 
ravages serious losses may result. 
Though commonly known as the red spider, it is a 
mite instead of a true spider, and for this reason Ewing of 
the Oregon Agricultural College has suggested the name 
“spider mite.” The fact that the body is seldom red is 
an additional reason for dropping the old name. Ewing 
has made a very thorough study of the spider mite, and 
we are indebted to him for most of the information which 
is given here in regard to its life history. Those who are 
especially interested in the spider mite should read Bul- 
letin 121 of the Oregon Agricultural College. 
According to Ewing and other workers, a single female 
may deposit from 51 to 94 eggs, and she may lay as many 
as 15 ina day. If a mite is feeding on soft, tender parts 
of favored host plants, and the temperature is high, the 
greatest number of eggs will be laid. In other words, 
