CONTROL OF CODLING MOTH IN COLORADO. 13 



All the plats, except the unsprayed checks and plat X, were given 

 the calyx treatment. The total number of applications varied from 

 five to seven, with six in the majority. Plats I, II, III, and IV 

 were given the same number of applications, three cover sprays for 

 the first brood and two for the second and third broods. Plats V 

 and VIII had but four cover sprays of lead arsenate, two for the first 

 brood and two for the later broods, and in addition plat V was pro- 

 vided with the codling-moth trap applied to each tree. Plats VI 

 and VII were sprayed throughout the season at the same time as 

 plats I to IV, but, as described later, received different treatment. 

 Plat IX received the largest number of applications, three cover 

 sprays for the first brood and the same number for the second and 

 third broods, making a total of six cover treatments. Plat X was 

 given five cover sprays, but, as previously mentioned, the calyx 

 treatment was omitted. Plats XI, XII, and XIII were given treat- 

 ment at the same time as the other plats having five cover applica- 

 tions, but the dusting method was substituted for the liquid. 



Arsenate of lead, powder, at the rate of 1 pound to 50 gallons of 

 water was used in all of the sprayed plats, except plat VII, in which 

 arsenate of lime, powder, three-fourths pound to 50 gallons, was 

 employed, and plat III, where 40 per cent nicotine sulphate, diluted 

 1 part in 800 parts of water, was used. Forty per cent nicotine 

 sulphate at this strength was also used with arsenate of lead in plat 

 IV, and in plat VI fish-oil soap, 2 pounds to 50 gallons, was used as a 

 spreader and sticker. Codling-moth traps, described on pages 35-38, 

 were used in plats I and V. Plats XI, XII, and XIII were dusted 

 with arsenate of lead mixed with hydrated lime as a filler in the pro- 

 portions shown in Table 9. In plat XI a dust mixture containing 

 20 per cent of arsenate of lead and 80 per cent of hydrated lime was 

 used; in plat XII, the arsenate of lead was decreased to 15 per cent 

 and the hydrated lime increased to 85 per cent. Plat XIII was 

 treated with 10 per cent of arsenate of lead and 90 per cent of hydrated 

 lime. Plats XIV and XV wore sprayed by the owner with arsenate 

 of lead and, as previously stated, plats XVI and XVII were untreated 

 throughout the season. 



The summary of results of these experiments is presented in 

 Table 10. 



