22 Farmers’ Bulletin 1261. 
during this period depends chiefly on the existing climatic con- 
ditions. Unlike most other red spiders which attack various other 
fruits, the red spider of the avocado confines its attacks to the upper 
surface of the foliage. This is also true of the thrips. 
Avocado orchards heavily infested with red-spider mites appear 
in a short time as if scorched by fire. The foliage attacked turns 
Ic. 15.—The avocado red spider: Defoliation caused by excessive infestation of these 
mites on avocado tree. 
brown and drops prematurely and frequently there is a heavy de- 
nudation as a result of their depredations (fig. 18). Their numbers 
increase so rapidly that the damage caused by the mites and thrips 
becomes noticeable in a very short period of time. Zhe grower should 
not delay spraying until the trees have commenced to turn brown, 
but should be on the lookout for the pests. Their presence on the 
trees in excessive numbers should be the signal for the grower to 
start control measures while the foliage is still green. 
