46 NEW YORK STATE MUSEUM 



sion, a whale oil soap solution, or a tobacco preparation, making 

 the application, if possible, just after a rain and using a coarse, 

 forcible spray. The advantage of spraying just after a rain is 

 that the moisture washes away in large measure the sticky excretion 

 which protects the young Psyllas and thus renders them more sus- 

 ceptible to the application. A coarse spray is more effective than 

 a fine, drifting fog because of its tendency to remove this protecting 

 secretion. 



San Jose scale (Aspidiotus perniciosus Comst.) . 

 The experience of the past year has but served to confirm the value 

 of early and thorough applications of a lime-sulfur wash for the 

 control of this pest. It is comparatively easy at the present time 

 to find orchards which have been infested by San Jose scale for 

 ten or fifteen years and yet show very few signs of its presence. 

 This is due, in our opinion, to two factors.. First, our methods of 

 spraying have been gradually perfected so that the work of later 

 years has been exceedingly thorough. Second, there has been a 

 marked development in the preparation of the lime-sulfur washes, 

 particularly in the commercial brands. There is no doubt as to 

 the value of a well prepared homemade lime-sulfur wash, whether 

 an excess of lime or a larger proportion of sulfur be employed. 

 The formulas generally used till within the last year or two, usually 

 called for a little more lime than sulfur. This preparation has 

 demonstrated its effectiveness time and again and must still be 

 regarded as an exceedingly valuable insecticide. Nevertheless, the 

 so called concentrated lime-sulfur washes, distinguished from the 

 earlier formulas by the use of approximately twice as much sulfur 

 as lime by weight, have given exceedingly satisfactory results and 

 possess several important advantages. This latter type of wash 

 can be made up months in advance without danger of crystallization, 

 provided freezing does not occur, and in a well made wash of this 

 character there is practically no sediment. These two considerations 

 are of great importance to the fruit grower who is frequently 

 pushed for time in early spring, when the spraying can be done to 

 best advantage, and is therefore unwilling or unable to take time 

 to prepare the wash while spraying operations are being conducted. 

 It is perhaps needless to add that this lack of sediment greatly 

 reduces the danger of clogging nozzles and consequent delay in 

 operations. Experiments have shown that the clear concentrated 

 lime-sulfur wash is as eft'ective, or at least nearly so, in destroying 

 the scale as the old type of wash with its large excess of lime and 

 frequently consideral)le sediment. The one trouble with the use 



