72 MASS. EXPERIMENT STATION BULLETIN 233 



Moths appear by the middle or last of May, and emergence continues for 

 five or six weeks. Four or five days after they emerge, tlie females begin to 

 lay eggs although, if the weather is cold or stormy, they may delay longer 

 before ovipositing. 



The incubation period of the eggs varies from four to twelve days, with 

 six to seven as the average, so that young larvae begin to appear about two 

 weeks after the emergence of the moths. 



Most of the larvae that mature before July 15 transform to moths the 

 same season. Therefore, the relative number of larvae leaving the fruit 

 before that time, in any year, determines the size and importance of the 

 second generation that season. 



The greater part of the summer brood moths emerge during tiie last week 

 of July and first ten days of August, and most of the larvae, or "worms", 

 of this brood appear from the 10th to the 20th of August. These larvae 

 remain in the fruit for three to six weeks, emerging in largest numbers during 

 September and early October. 



In Massachusetts, there has been found to be a slight overlapping of the 

 two generations, so that from the time fruit is set until harvest there are 

 but few days when infestation may not take place. 



Insectivorous birds, predaceous and parasitic insects, and unfavorable 

 weather conditions provide a natural check to the Increase of this pest, but 

 they cannot be depended on to give satisfactory control. 



Preventive measures such as careful thinning, banding of trees, the use of 

 l)ait traps, disposal of culls, and protection of storage houses are valuable 

 as supplementing spraying. 



Spraying, on the whole, has proven more effective than dusting. It is the 

 most important phase of codling moth control and should be thorough and 

 timely. 



The most important sprays in the control of this insect are the calj-x (No. 3 

 in the schedule) and the post-calyx sprays (Nos. 4 and 7 in the schedule). 



Publication of this Document approved by the Commission on 

 Administkation and Finance. 



6,000. 3- '27. Oi-der8311. 



