CIRCULAR 2 7 0, U. S. DEPARTMENT OF AGRICULTURE 



very few eggs are laid if the temperature at this time is below 60° F. 

 Under favorable temperatures most of the eggs are laid during the 

 second, third, and fourth evenings after the moths have emerged, but 



in the spring cool weather may prevent egg 

 laying altogether for a week or more. The 

 eggs (fig. 4) are pearly white, about the size 

 of pinheads, and resemble thin convex disks. 

 A few days after it is laid a red ring appears 

 in the egg, and the day before the worm 

 hatches a black spot, the head of the worm, 

 is easily seen. Most of the first-brood eggs 

 are laid on the leaves surrounding the small 

 fruits. 



The earliest-laid eggs are usually subjected 

 to cool weather and the worms do not hatch 

 for 12 to 14 days. As the temperature be- 

 comes higher, the incubation period of the 

 egg shortens, the minimum being 5 days, 

 although in extremely cool weather it may 

 be as long as 3 weeks. Worms are hatching 

 from eggs and entering the fruit for about 5 weeks, and are most num- 

 erous during June. These worms feed in the fruit for about 3 weeks 

 and then leave it and spin cocoons. About 75 percent of them con- 

 tinue their development into pupae and moths, but the others remain 

 in the cocoons until the following season. The worms that transform 



Figure 3.- 



-Codling 

 X 3. 



moth. 



Figure 



-Codling moth egg 



apple leaf; right, single 



pass through the pupal period in about 2 weeks, and the first individu- 

 als of the second brood of moths appear early in July. After this time 

 moths are present in large numbers until cool weather in the fall, the 

 first period of stormy weather in September usually ending the ac- 

 tivities of the moths for the season. Many eggs of the second brood 

 are laid on the fruit, and during the warm weather of July and August 



