1908.] PUBLIC DOCUMENT- -No. 73. 139 



best results, due to the more thorough coating of the foliage, 

 and required less poison ; but the cost of labor where it is used 

 was considerably greater than with the solid stream. On the 

 other hand, the solid-stream spray permitted of more rapid 

 work, reduced the amount of climbing to be done, but required 

 a much greater quantity of insecticide as compared with the 

 mist spray. The superintendent is of the opinion that both 

 systems of spraying are desirable in badly infested towns ; that 

 the proper field of usefulness of hand sprayers or low-pressure 

 power outfits throwing a mist spray will be found in the treat- 

 ment of orchards, trees on private estates, shrubbery and road- 

 sides, or where exterminative measures are necessary. The 

 high-pressure power outfits with the solid-stream spray are most 

 useful in the treatment of tall shade trees, woodland, and where 

 the wholesale destruction of the caterpillars in the shortest pos- 

 sible time is desired. 



While in the past years we never had a bona fide instance of 

 the death of live stock from grazing beneath trees where the 

 mist spray had been used, during the past year a number of 

 cows were killed by feeding in orchards and woodlands where 

 the solid-stream spray had been employed. The reason for this 

 is not far to be sought. With the solid stream a very much 

 larger quantity of the poison is thrown into the trees, and much 

 of it falls to the ground and thoroughly poisons the grass. In 

 some cases, in their most commendable desire to wipe out the 

 moth pests, the local superintendents increased the proportions 

 of poison used, as recommended by the central office, from 10 

 pounds of arsenate of lead to 100 gallons of water, to 15 or 20 

 pounds of 'the insecticide to the same quantity of water. Notices 

 giving warning that poison was being used on the premises were 

 generally posted throughout the sprayed districts, and farmers 

 were notified to cut the grass in the orchards before spraying 

 operations commenced, and also warned against pasturing their 

 cattle in the woodlands which had been sprayed. In spite of 

 these precautions, the disastrous results above mentioned oc- 

 curred in several cases. This indicates the necessity in the 

 future work of adopting much greater and more complete pre- 

 cautions than were taken in the season of 1907. 



One interesting and very gratifying result of the general 



