92 



ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



dip and first used in the Middle West against the San Jose scale by 

 Professor Forbes in Illinois. The following comparison shows it 

 slightly less effective than the orchard-boiled lime and sulphur Avash, 

 but successful enough to justify use under special conditions, and 

 presents in brief a comparison of the " Rex " lime-sulphur wash and 

 the homemade lime-sulphur spray as used in this test against the 

 Howard scale of pear. 



Spray. 



Formulae. 



Date 

 sprayed. 



April 6 

 April 5 



Percentage 



of scales 

 dead at ex- 

 amination, 

 April 25. 



Percentage 

 of pears in- 

 fested atpick- 

 ingtime, Au- 

 gust 17. 



" Rex" 



"Rex," 1 part; cold water, 8 parts. 



(Lime, 15 pounds per 50 gallons. ) 

 Lime, 15 pounds; sulphur, 15 pounds; 



watei, 50 gallons; boil 45 minutes. 



84.4 

 93.8 

 55.0 



2.8 



Lime and sulphur 



Check 



.6 

 96.1 











Two means of comparison are to be had in the above table, the 1 

 first as indicated in the count of the percentage of scales dead upon 

 the bark of the tree upon April 25, at which time the Rex lime- 

 sulphur gave 84.4 per cent dead, the lime-sulphur wash 93.8 per cent 

 dead, and the plat given no spray 55 per cent scales dead of those 

 counted. As will be noted, this count was made only twenty days 

 following spraying, and a later examination would have yielded a 

 higher percentage killed in both of the treated plats, due to longer 

 action of the adhering spray. 



The second means of comparison, and that of more practical bear- 

 ing to the fruit grower, is shown in the table as a count of the per- 

 centage of pear fruit showing the pits from infestation, found on 

 the surface in a count made on August IT, at time of harvest. This 

 comparison shows but 2.8 per cent pears infested upon an average 

 borne upon the tree in the plat sprayed with the Rex. The lime- 

 sulphur plat gave 0.6 per cent infested pears or less than one per 100, 

 while the check or unsprayed trees gave 96.1 per cent infested. In 

 each case many hundreds of pears were counted in securing these 

 ratios. They show good results with both sprays, but a slight 

 advantage with the orchard-boiled mixture. It was also apparent 

 that pears borne upon badly infested trees not treated would almost 

 without exception show infestation sufficient to exclude them for 

 market purposes. 



With one proper dormant spray of lime-sulphur wash, it is shown 

 that the Howard scale may be controlled, and, unlike the San Jose 

 scale, it seems probable that one spraying in two years will accom- 

 plish this result. 



