56 MASS. EXPERIMENT STATION BULLETIN 23:3 



A less important type of injury is caused by warms which, having eaten 

 into the side of the fruit a distance of one-eighth of an inch or less, have been 

 killed by birds, other insects, or poison, or have been dislodged by wind or 

 rain. Such injury usually heals quickly and is called a "sting". However, 

 the resulting scar materially reduces the value of the fruit. 



Description and Habits 



Fruit growers should be able to recognize the codling moth in its different 

 stages of growth, in order to follow its development tlirough the season and 

 to understand the fundamental principles of its control. 



The Moth. (See Plate I.) The adult moth is comparatively small, the 

 female having a wing spread of about three-fourths of an inch, and the male 

 slightly less. The fore wings are brownish gray crossed by numerous dark 

 lines, giving a characteristic "watered silk" appearance. Near the tip is a 

 large bronze-colored spot or band. The hind wings are light grayish-brown, 

 becoming slightly darker toward the margin. Because of its size, color, and 

 markings, the moth is quite inconspicuous when at rest, and consequently 

 seldom observed in the orchard. 



Of the moths which emerge first in the spring, males slightly predominate 

 but^ over the season as a whole, the number of males and females is approx- 

 iriiately the same. 



Tlie moths as a rule remain quiet during the day and in cold, wet or cloudy 

 weather, becoming active at dusk. The number of eggs per female moth 

 varies greatly and is strongly influenced by sudden changes in temperature. 

 Although the earliest emerging females may deposit very few eggs, the aver- 

 age number is twenty to twenty-five. In midsummer when more uniform and 

 favorable weather prevails, the average number increases to thirty or forty. 



The length of life of the moths varies according to sex and, to a consider- 

 able degree, according to the time of year they appear. In cold weather, 

 activity is slight and the moths live from two to three weeks. Under favor- 

 able weather conditions, they become more active and the length of life cor- 

 respondingly shortens. The average life of spring moths as observed in 1924. 

 and 1925 according to the time of emergence was as follows: 



Date of Emergence Length of Life, Days 



Males Females 



May 25— June 5 13—16 18—21 



June 6— June 15 12—13 14—15 



June 16— June 30 8—9 10—12 



There is no such wide variation shown by the summer brood of moths where 

 the average life of the males is eight to ten days, and of the females eleven 

 to twelve days. 



The Egg. Tlie eggs resemble small oval discs, pearly white in color, and 

 about the side of a pin head. They are deposited singly on the leaves, twigs 

 or fruit, where they appear as milky white spots (See Plate I.). A few days 

 after they are laid, the developing embryo is seen as a faint red ring, which 

 gradually widens and deepens in color. A day or two before hatching, a 

 conspicuous black spot, the head and thoracic shield of the larva, appears 

 near the margin. 



