f ested, with the insects showing a tendency in places to form clusters ; 

 4, a tree with scales which show a decided tendency towards the for- 

 mation of clusters, yet have parts but slightly infested; 5, a mod- 

 erately infested tree, the scales being fairly abundant over the entire 

 tree, and frequently forming groups or clusters; 6, a tree mostly 

 moderately infested, but with some parts so badly infested as to be 

 evidently suffering; 7, a tree considerable parts of which are badly 

 infested, yet having parts infested to only a moderate degree; 8, a 

 tree for the most part badly infested, but not incrusted, evidently 

 suffering from the attack of the scale ; 9, a tree badly infested, with 

 some parts incrusted; and 10, an incrusted tree. Cases where the 

 scale was peculiarly distributed on a tree, making its classification, 

 difficult, were decided by consultation. I am told, however, by the 

 inspectors grading these trees, that, in practice, the grades between 

 1 and 10 were essentially estimates of the relative parts of the sur- 

 face of the tree occupied by the scales, a grade of four, for example, 

 indicating that twice as much surface was infested as in grade 2, 

 and so on. It was found that the. trees could be readily graded, for 

 the most part, on this scale and that the two men working inde- 

 pendently would agree almost exactly in their estimate of the inten- 

 sity of the infestation. The orchard containing originally 1200 trees 

 was generally and badly infested, while the other, containing originally 

 1600 trees, was infested much more moderately. 



THE EXPERIMENTAL PLOTS 



Four insecticides were tested in this year's operations in a way 

 to compare for each the relative effects of a single fall application, 

 a single spring application, and two applications, one in fall and 

 the other in spring. The more heavily infested orchard (No. I), 

 showing an average infestation of 7.4 degrees, was divided into five 

 plots, one of which was reserved as a check, and the remaining four 

 were treated fall and spring with the four insecticides. The check 

 plot was six rows wide, plots 2 and 3 were fourteen rows wide, and 

 plots 4 and 5, thirteen rows. Orchard No. II, the infestation of 

 which averaged 3.9 degrees, was divided into nine plots, one of which 

 was reserved as a check, the remainder being used to test the effect 

 of a single application of- each of the four insecticides in fall and in 

 spring. These plots were six rows wide, except the one nearest the 

 check (7), which was made ten rows wide in order that a more liberal 

 allowance might be made for the influence of the check plot upon the 

 experimental plot adjoining than for the effects of adjacent experi- 

 mental plots upon each other. 



INSECTICIDES 



The lime-sulphur mixture applied was the 15, 15, 50 preparation 

 in general use by us in 1908. Fifteen pounds each of sulphur and 



