= The Avocado: Its Insect Enemies. 11 
surface of the foliage or fruit, and the sooty-mold fungus is thus 
furnished with a Papdits in which to develop. The second molt of 
the larvee occurs in an average of from 5 to 6 days, and the third, 
in an average of 7 days. The pupa stage during the spring and sum- 
mer erenths averages from 15 to 30 days, ahd: during the fall and 
winter from 3 to 6 months. The successive larval stages are quite 
similar in general appearance, varying only in size. 
There are, on an average, three generations with a partial fourth 
varying according to locality and temperature conditions, much as 
in the case of the dictyospermum scale. Toward fall, usually the 
latter part of October, as the foliage becomes dormant, the white fly 
ceases its activities and goes into the winter in the pupa stage. 
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lic. 6.—The avocado white fly: a, Clean fruit; b, top of avocado covered with sooty- 
mold fungus. 
HOW IT MAY BE CONTROLLED. 
The white fly may be controlled by spraying during the fall with 
an oil emulsion, preferably just as the foliage is commencing to 
harden, and repeating the operation some time during the spring 
after the fruit has set. The fall spraying for white flies should be 
made with 1 part oil emulsion to 70 parts of water and the spring 
spray should have the strength of 1 to 80. In spraying for white flies 
with an oil emulsion it is important that no free oil separates dur- 
ing spraying, and that the spray be directed so as to reach the 
lower surface of the foliage. Experience has shown that in spraying 
operations against the white fly spray rods are more satisfactory as 
it is quite difficult to reach the lower surface of the foliage with the 
spray gun, because the avocado tree bears branches close to the soil 
(fig. 8) and the foliage on these branches is more readily reached 
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