180 DECIDUOUS FEUIT INSECTS AND INSECTICIDES. 



A power outfit should be used in spraying, maintaining 200 pounds 

 pressure. Bordeaux nozzles equipped with an angle and used from 

 a tower give the highest percentage of clean fruit. 



SUMMARY. 



In the Santa Clara Valley of California there occurs one full gen- 

 eration and one partial generation of the codling-moth larvae. 



The following is a brief summary of the life cycle : The overwintered 

 larvae pupate from the middle of February until May, the moths 

 issuing about six weeks later through a period extending from the 

 latter part of March until the middle of June. Eggs are deposited 

 about 3 days after emergence, and these hatch in about 12 days, the 

 red ring appearing in 2 or 3 days and the black spot some 8 days 

 later. The first-brood larvae enter the fruit shortly after hatching 

 and remain there for about 5 weeks. They are present in the fruit 

 from the last week in April until the last week in July, a range of 3" 

 months, or nearly three times their average larval life. After leaving 

 the fruit the full-grown larva seeks some crevice in the bark on the 

 main trunk or on the larger limbs of the tree and there spins its 

 cocoon, transforming after a few days into a pupa. In confinement 

 a great variation occurs in the time between spinning the cocoon and 

 actual pupation, but in the field there is probably not nearly such a 

 variation. The first-brood pupal stage averages 21 days, only half as 

 long as the corresponding stage of the spring brood, a fact due, 

 undoubtedly, to the considerably higher temperature influencing the 

 former brood of pupae. First-brood pupae are present from about 

 the middle of June until the middle of September, although the two 

 years 1910 and 1911 (see figs. 31 and 39) show a considerable diver- 

 sity on this point; for in 1910, the warmer of the two years, the first- 

 brood pupae were present three weeks earlier. Similarly the first- 

 brood moths emerged just so much earlier in 1910. A fair proportion 

 of the first-brood pupae overwinter, and for this reason some individ- 

 uals remain in the immature forms for 10 or 11 months. The first- 

 brood moths begin to deposit eggs 3 days after issuing, and these 

 eggs hatch in 11 days, or if the season is cold in 12 or 13 days. The 

 red circle and black spot appear as in the first-brood eggs. The 

 second-brood larvae remain in the fruit about 50 days, and they are 

 present from the latter half of July until the middle of October, a 

 period of about 80 days, and thus shorter in comparison to the length 

 of the larval stage than in the first-brood larvae. This is accounted 

 for by the shorter period of adult emergence, causing a shorter period 

 of egg deposition in the first-brood moths as compared with that of 

 the spring-brood moths. All larvae of the second brood winter over 

 and form the great bulk of overwintering larvae. Doubtless if the 



