INJURIOUS AND BENEFICIAL INSECTS OP CALIFORNIA. 



439 



and some begin to hatch when the first cluster buds appear in the spring 

 (March and April). The young caterpillars at once enter the opening 

 buds and begin feeding. As the foliage grows the larvae roll and tie 

 the leaves into compact hiding places which are lined with silken webs. 

 The young fruit is also attacked. The larval stage lasts from twenty- 

 four to thirty-five days. When fully matured they transform to pupsB 

 (last of April and in May) usually within the leaf roll, and in from 

 nine to nineteen days the adults emerge. The females begin to lay eggs 

 within two or three 

 days after they ap- 

 pear (last of May to 

 July). There is but 

 o n e generation a 

 year. 



Nature of Work. — 



The first work of the 

 larva 1 is in the open- 

 ing buds and upon 

 the young leaves, 

 blossoms and fruit, 

 all of which may be 

 almost or entirely 

 destroyed. Webs are 

 spun around the 

 branches, leaves and fruit, fastening all together. Infested parts of 

 the tree turn brown or the tree may be partially or entirely defoliated 

 in severe cases of infestation, where control measures have not been 

 employed. Fruits attacked when young develop into very irregular 

 and unsightly shapes and are unfit for market purposes. Because of 

 the defoliation the trees are often unable to produce crops for the 

 next year. 



Distribution. — Mr. Geo. P. Weldon, who first called attention to this 

 moth in California in 1913, has found it in the following counties: San 

 Diego, Alameda, Solano, Tehama, Santa Clara. San Benito, Santa Bar- 

 bara and San Bernardino. The writer has received it from Monterey. 



Food Plants. — The folloAving food plants are recorded: alfalfa, 

 apple, apricot, cherry, currant, elm, gooseberry, locust, onion, pear, 

 plum, poplar, prune, quince, raspberry and rose. 



Control. — It has been fully demonstrated by Mr. Weldon that the 

 application of miscible oil sprays to kill the eggs during the winter is 

 by far the best remedy so far discovered and has given such splendid 

 results as to make further experimentation hardly necessary. During 

 the winter of 1913 Mr. Weldon checked up his experiments previously 

 made in Colorado with miscible oils and other sprays and the efficiency 

 of the former was far ahead of anything else tried, including oil emul- 

 sions, lime-sulphur and other commercial sprays. The miscible oils 

 may be had from any spray manufacturing company. 



Fig. 447. — Winter egg-masses of the fruit-tree leaf- 

 roller, Archips argyrospila Walker. Enlarged three times. 

 Specimens collected in San Diego County by Geo. P. 

 Weldon. (Original) 



