. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. THE GRAPE-BERKY MOTH. 57 The results of the spraying operations for this season are quite indefinite and serve only to bring out the great irregularity in infesta- tion, its progress throughout the season, and the difficulty in laying out a plat arrangement which will show accurately the effect of spray treatment against this pest. That some benefit did result from the spray application is indicated by the fact that in a comparison of infestation in Plats V, VI, and VII, where the infestation was lighter but more
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. THE GRAPE-BERKY MOTH. 57 The results of the spraying operations for this season are quite indefinite and serve only to bring out the great irregularity in infesta- tion, its progress throughout the season, and the difficulty in laying out a plat arrangement which will show accurately the effect of spray treatment against this pest. That some benefit did result from the spray application is indicated by the fact that in a comparison of infestation in Plats V, VI, and VII, where the infestation was lighter but more uniform than on the opposite side of the vineyard, there was throughout the season a greater infestation on the unsprayed plat than on the two adjacent sprayed plats. There was not sufficient difference in the weight of fruit from the different plats to indicate a commercial value resulting from the use of arsenate of lead as against arsenite of lime. VINEYARD EXPERIMENTS WITH POISON SPRAYS IN 1908. The spray work for 1908 was conducted in the same vineyard as in 1907. The plat arrangement, however, was changed. The number. Fig. 21.—Plat arrangement of poison-spraying experiments against the grape-berry moth in the vineyard of Mr. W. S. Wheeler, North East, Pa., 1908 and 1909. (Original.) of plats was reduced to four. Plat I consisted of 5 rows, Plat II of 12 rows, Plat III of 13 rows, and Plat IV of 5 rows. The position of the check or unsprayed plat was also changed. Checks were left in two places. In the west section 10 vines were left unsprayed on the east end of all the rows of the four plats; in the east section 15 vines were left unsprayed on the east end of all of the rows of the four plats. (See plan of plat arrangement, fig. 21.) The dotted line running across the plats near the east end of both sections indicates the loca- tion of the unsprayed check vines; these portions thus separated are numbered Plat Va and Plat V6, respectively. This rearrangement of plats wa
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