10 



TREATMENT OF ORCHARDS. 



In orchards well sprayed during the dormant period for the San 

 Jose scale each year, the oyster-shell and scurf}" scales will rarely 

 prove troublesome. While these insects, by reason of wintering in 

 the egg stage under the protecting female scales, are less susceptible 

 to washes effective against the San Jose scale, yet the treatments 

 will in most cases keep them reduced below injurious numbers. 



In orchards where spraying for the San Jose scale is unnecessary and 

 where the oyster-shell or scurfy scales are troublesome, specific treat- 

 ments become necessary. There is considerable difference of opinion 

 among entomologists as to the effectiveness of sprays applied during 

 the dormant season to effect the destruction of the eggs, but there is 

 greater uniformity as to the effectiveness of spraying shortly after 

 the young have hatched and before there has been time for the forma- 

 tion of a thick protecting scale. 



Thus Messrs. Parrott, Beach, and Sirrine,« referring to the scurf}^ 



scale, state: 



During the work of the past two years opportunities have been given to note 

 the effects of the sulphur washes upon this species. In several instances where the 

 infestation was moderate, such treatment has usually checked the further develop- 

 ment of the scales. "When the incrustation was heavy, the results attending the 

 application of the washes have shown some variation in the amount of reduction oi 

 the scales, but there has usually been a very appreciable destruction of the insects. 



Writing of the oyster-shell scale, Mr. William Stuart says:'' 



Early spring applications do not appear to be a practicable method of eradicating 

 the oyster-shell scale. Summer treatment of infested trees, soon after the young 

 have hatched, with dilute kerosene emulsion, whale-oil soap, or tobacco infusions 

 affords a much more effective means of combating this pest. 



Experiments were made by Mr. Stuart in the use of the cooked 

 lime-sulphur wash in 1904, and the kerosene-limoid mixture in 1905. 

 In 1906 tests Were made of the cooked lime-sulphur sprays. All 

 applications were made during the dormant period of the trees. 



The Rev. Chas. J. S. Bethune states :'' 



Owing to the large number of applicants who were desirous of obtaining information 

 on the best methods of combating the oyster-shell bark louse, it was decided to carry 

 on a number of experiments here, to test the efficiency of the -"'arious insecticides 

 commonly used against scale insects. 



Of all the spray mixtures tried, the well-known lime, salt, and sulphur wash gave 

 the best results. 



Tho lime, sulphur, and caustic soda, and the lime, sulphur, and sal soda were also 

 tried, but without quite such good results. The lime, sulphur, and caustic soda 

 proved to be a little superior to the lime-sulphur and sal soda, owing to its apparent 

 power of better penetration. 



a Bui. 262, N. Y. Agr. Exp. Sta. (Geneva), 1905. 

 b 19th Ann. Rep., Vermont Agr. Exp. Sta., p. 294, 1907. 

 c32d Ann. Rep. Ont. Agr. Coll. and Exp. Farm, p. 48, 1906. 

 [Cir. i21] 



