1907.] PUBLIC DOCUMENT — No. 33. 201 



little, as the plant it is on furnishes all the food supply 

 needed ; but as these plants become thoroughly covered with 

 the scales, the young find it more difficult to obtain their food 

 without wandering farther from where they were born, and 

 apparently more of them nnder these conditions get upon the 

 feet of birds or larger insects which alight where they are, 

 and are thus carried away to infest other parts. The result of 

 this is a general infestation of the region, following four or five 

 years after the local infestation ; and it is probable that this 

 condition of affairs was reached generally in Massachusetts 

 about 1904. .Following this were two summers extremely 

 favorable for a rapid increase of these pests ; and we now 

 find them in great abundance in many places wliere their 

 I^resence has not before been suspected, and quite generally 

 scattered through the State. 



Whether this explanation, which naturally is more or less 

 theoretical, be correct or not, the fact remains that the corre- 

 spondence of this station shows that the San Jose scale was 

 probably present in one or more somewhat restricted areas in 

 nearly every town in Massachusetts east of the Connecticut 

 River in 1904; while at the present time it would probably 

 be easy to find it in a dozen places in each of these towns, 

 and as frequently on large, old trees as on recently set 

 ones. 



Though this insect attacks a large number of kinds of 

 plants, those of most importance to man are the fruit trees 

 and certain ornamental trees and shrubs; and these, accord- 

 ingly, are the ones which will receive attention in the way of 

 treatment. A number of extensive studies in the treatment 

 of the San Jose scale were begun at this station in 1902, at 

 which time the conclusion was reached that the most successful 

 treatment was obtained by the use of the lime and sulfur 

 mixture. Farther experiments along this line have been 

 made as opportunities offered, and tKe results reached still 

 confirm that conclusion. Last spring over eight hundred 

 trees belonging to the college were sprayed with a number 

 of different preparations, and a study of the results was made 

 during the entire summer and fall. The inconvenience in 

 making the lime and sulfur mixture, resulting from the neces- 



