478 BOARD OF AGRICULTURE. [Pub. Doc. 



ON THE VALUE OF GLUCOSE IN SPRAYING. 



A. H. KIKKLAND, M.S. 



In the spraying operations against the gypsy moth, limited as 

 they are to a season of about four weeks, and usually hampered 

 by frequent rains, our aim has been to apply the insecticide, 

 arsenate of lead, in as great a strength as is consistent with 

 economy. Producing the poison, as we do, at a cost not exceed- 

 ing 7 cents per pound for the mixture, and with perfected spray- 

 ing apparatus whereby nearly all wasting of the spray has been 

 eliminated, it has been found practical to apply the insecticide at 

 the rate of 25 pounds of the mixture (or 12^ pounds actual arse- 

 nate of lead) to 150 gallons of water, and in field work this pro- 

 portion has yielded excellent results. The custom of adding 

 glucose to the spraying mixture at the rate of 4 to 6 quarts to 150 

 gallons has been followed from the earliest days of the work, it 

 being considered that this substance was of value in retaining the 

 poison upon the foliage. The cost of glucose has been a consid- 

 erable item, the labor of dissolving it a greater one ; and, since 

 the benefit derived from its use has been repeatedly questioned, 

 the matter was made a subject for investigation during the past 

 summer. 



The opinion has been held that the addition of glucose to the 

 spraying mixture increased the amount of poison adhering to the 

 foliage, thus making the insecticide more effective. This being 

 the generally accepted assumption, it seemed that the fact could 

 be tested in at least three different ways. 



1. Tests by Inspection. 

 On June 14, 1898, five areas of oak brush were sprayed with 

 arsenate of lead, at the rate of 12|- pounds to 150 gallons of 

 water, one area being sprayed without the use of glucose, the re- 

 maining four being treated with various amounts of glucose 

 mixed with the spraying solution. The exact treatment was as 

 follows : — 



