18 BULLETIN 1273, U. S. DEPARTMENT OF AGRICULTURE 



Although the experiments outlined above were conducted on a 

 comparatively small scale, the results indicate very clearly that the 

 arsenical sprays applied while the larvae are feeding in the spring 

 will kill a large percentage of them. In the field tests summarized 

 in Table 8, a single application when the blossoms were showing 

 pink apparently reduced the number of healthy larvse present 71 

 per cent, a single application just after the petals had fallen reduced 

 the number 79 per cent, and where both were applied the num- 

 ber of healthy larvse was reduced 92 per cent. On the trees receiv- 

 ing the earlier application the number of nests was less than half the 

 number found on trees receiving only the calyx application or none 

 at all. The calyx spray comes too late to prevent much of the cur- 

 rent season's injury, but kills a large proportion of the larvae, and 

 reduces the numbers of the next generation which is to feed during 

 the summer and the following spring. No experiments were made 

 with dusting, but a careful treatment with dust would probably 

 be about as effective with this species as the liquid. 



These results bear out for the most part those reported by the 

 most recent workers on the bud moth. DuPorte (21) reports the 

 combined efficiency of the two pre-blossom sprays and the calyx 

 spray to be 86.5 per cent, and the efficiency of the pink and calyx 

 treatments combined to be 80 per cent. Sanders and Dustan (22) 

 report' that the two most efficient spray applications for bud moth 

 control (referring in general to the four species discussed) are: 

 One when the leaves are the size of a dime, and a second immediately 

 before the blossoms open. Further confirmation of the results noted 

 above will be found in the fact that well sprayed orchards, which 

 always receive the calyx application, and usually the pink cluster- 

 bud spray, are seldom seriously troubled by the bud moth. 



In case of a severe infestation, in addition to the pink and calyx 

 applications it would probably be advisable to put on an arsenical 

 spray about midway between the delayed dormant and pink applica- 

 tions, in order to keep the rapidly growing foliage as well coated as 

 possible with the poison. 



The hatching of the eggs extends over a period of a month or more, 

 beginning about the middle of July under average Connecticut con- 

 ditions. The tiny larvae feed on the foliage and to a certain extent 

 on the fruit during the remainder of the summer, but their feeding 

 areas are small and for the most part confined to the lower sur- 

 faces of the leaves and under the shelter of a web of silk, or in 

 protected places where fruit and leaves are in contact. Some suc- 

 cess has been reported with the use of arsenicals against the young 

 larvae during this period, but in view of the fact that the bud moth 

 may be controlled satisfactorily by the routine spring applications, 

 the later treatments will probably seldom be necessary. If a single 

 summer application is to be made, it will be best to wait until 

 nearly the end of the hatching period, which would be early in 

 August under Connecticut conditions. Care must be taken to cover 

 with the spray the lower surfaces of the leaves, where the majority 

 of the larvae feed. 



