26 MISC. PUBLICATION 168, U. S. DEPT. OF AGRICULTURE 



Codling Moth Injury 

 (Carpocapsa pomonella (L.) ) 



OCCURRENCE, SYMPTOMS, AND EFFECTS 



Wormy fruits, injured by the larvae of the codling moth, may 

 be found on the market among apples and pears grown in all 

 producing sections of the United States, the proportion of injured 

 fruit varying with the locality in which the fruit was grown and 

 the care with which the fruit was grown and graded. 



Typical wormy apples (pi. 15, B) are too well known to require 

 an extensive description. The worm may enter at the calyx, at the 

 side, or at the stem end of the fruit, and it tunnels more or less 

 directly to the core. The area surrounding the core becomes a mass 

 of dark-colored frass and fragments of fruit tissue. In leaving 

 the fruit, the larva usually goes directly from the core to the 

 side. The tunnels permit the entrance of blue mold, Alternaria, 

 the black rot fungus, and other rot-producing fungi. A second 

 type of damage, known as "sting injury," or "worm sting," con- 

 sists in small, discolored, hardened, often depressed spots, usually 

 with a tiny hole at the center (pi. 2, G). These spots are caused 

 by larvae that have consumed a fatal dose of poison but have 

 managed to burrow a short distance into the fruit before death. 



CAUSE 



The worm, or larva, causing worminess in apples is about % 

 inch in length when full-grown, is cream white to pink white 

 in color, and has a dark-brown head. The insect hibernates in the 

 larval stage in cocoons in bark crevices, in trash on the ground, 

 in orchard lug boxes, and in packing sheds. The adults begin to 

 emerge during or shortly after the blooming period. The moths 

 have a wing expanse of % to % inch; they are brownish gray 

 in color and have a dark-brown spot crossed by two golden bars 

 at the tip of each fore wing. 



CONTROL MEASURES 



For many years the standard material for control of the codling 

 moth was lead arsenate. In some localities control with this ma- 

 terial was very satisfactory, but in others lead arsenate was 

 inadequate even with eight or more applications in the course 

 of a season. Use of lead arsenate also sometimes resulted in 

 excessive residues on harvested fruit, which had to be removed 

 by washing or otherwise. During the last few years DDT has 

 given outstanding control of the codling moth, and it is now being 

 used in most localities where difficulty has been experienced in 

 worm control. Use of DDT has unfortunately resulted in marked 

 increases in other orchard pests, especially mites, red-banded 

 leaf roller, and woolly apple aphid. Fully satisfactory programs 

 for control of all of these pests have not yet been developed. 

 More recently parathion has come into use for codling moth con- 

 trol. In planning a season's codling-moth-control operations, grow- 

 ers should therefore be guided by the current recommendations 

 issued by State agricultural experiment stations or by the United 

 States Department of Agriculture. 



(See 47, 48, 93, 101.) 



