14 



CIRCULAR 270, U.S. DEPARTMENT OF AGRICULTURE 



occasional very serious outbreaks have occurred elsewhere, and may 

 occur again. In the past the insect has periodically become of prime 

 importance, remained so for a few years, and then again subsided into 

 relative up importance. It is a native insect which originally fed on 

 the foliage of a number of wild plants. 



LIFE HISTORY 



The fruit tree leaf roller passes the winter in the egg stage. The 

 eggs (fig. 15) are laid in masses of 100 or more, and are rather in- 

 conspicuous, oval, grayish or 

 brownish patches, nearly one 

 fourth inch long, on the limbs, 

 twigs, and trunks of the trees. 

 The eggs hatch as soon as the 

 buds begin to open. The cater- 

 pillars gnaw small holes in the 

 surface of the egg mass, through 

 which they escape, and hatched 

 egg masses may be identified by 

 these perforations. The cater- 

 pillars are quite active, crawling 

 backward about as rapidly as 

 forward, and often letting them- 

 selves to the ground on a thread 

 if disturbed. They become full 

 grown in June and at that time 

 are about three fourths inch 

 long, and are green with black 

 heads. They transform to 

 brown pupae in the rolled-up 

 leaves, and the moths (fig. 16) 

 emerge about 10 or 12 days 

 later. These are a little larg- 

 er than codling moths, the ex- 

 panded wings measuring about 

 three fourths inch across. They 

 are cinnamon brown, with 2 or 3 

 light-yellowish markings. The 

 eggs are laid during June and 

 July, each female depositing all 



Figure 13.— Leaf-roller iDjury to apple foliase. f \ eT eeSS in a single mass, 



unless disturbed. These eggs hatch the following spring. 



CONTROL 



The most effective means of controlling the leaf roller is by destroy- 

 ing the eggs with an oil spray in the spring before they have hatched. 

 Any of the emulsions or miscible oils that are satisfactory for scale 

 control may be used for this purpose. light ^ infestations may be 

 treated with an emulsion containing 4 percent of oil, as this kills most 

 of the eggs, but for serious outbreaks, when large numbers of eggs are 

 on the trees, the strength of the dilute emulsion should be increased 

 so that it contains 7 percent of oil. Spraying should be done during 

 the first settled period of mild weather. It should not be done just 

 before a rain or when temperatures lower than 25° F. are likely to 



