Spraying experiments against the codling moth were carried on upon the Smart orchard until the number of worms per tree was reduced to such an extent that no accurate comparisons could be made between different treatments. As a result of the work on this and other orchards, practically every commercial orchard in the valley was by this time well sprayed and the worms reduced to a point where one driving spray per season would keep them under control.
In the meantime a number of questions arose which required very wormy conditions to adequately investigate. Search was therefore made for orchards of commercial varieties in which these conditions could be found. Salt Lake valley, which was largely settled in the early fifties and has a large number of old, mixed and exceedingly wormy orchards, was investigated, and three young, well cared for commercial orchards were selected for spraying tests. These were of different ages and located in different parts of the valley and were expected to furnish different conditions of infestation for comparison. They were also expected to blossom on succeeding dates and to be subject to different frost conditions.
Ball, E. D. and Ball, W. M., "Bulletin No. 129 - Codling Moth Studies in 1911: The Driving Spray Under Excessively Wormy Conditions" (1913). UAES Bulletins. Paper 80.