REPORT OF THE ENTOMOLOGIST AND BOTANIST 71 



SESSIONAL PAPER No. 16 



thcro were only eight or ten weeds which were noticeably destructive In any one 

 locality, and that if the nature of these were borne in mind the work of destroying 

 tliem would be much simpler. 



' Special instructions were given for the eradication of wild oats, stinkweed, per- 

 ennial oi: field sow thistle and Canada thistle. Particular stress was laid on the value 

 of harrowing-, or using a weedcr on growing crops for the destruction of the seedlings 

 of all annual weeds while they were small and easily killed. . Grain crops should only 

 be harrowed when the land is in proper condition for harrowing, and not before the 

 young grain is three inches high. 



Jas. Fletcher, 



'Entomologist and BotanisL' 



Officials of the Divisiox. 



The staff of the Division of Entomology and Botany consists of the following in 

 addition to the writer, who has held office since July 1, 1887. 



J. A. Guignard, B.A., Assistant Entomologist and Botanist, and Curator of the 

 Botanical Collections; appointed April 11, 1892. 



Arthur Gibson, Assistant Entomologist and Curator of Insects; appointed April 

 1, 1893. 



Berthold Nothnagel, in charge of the Experimental Grass Plots since 1800. 



Spraying w^th Arsenites. 



At the time the Experimental Farm system was organized, the words ' spraying ' 

 and ' spraying pump ' were actually unknown as the names of a method and implement 

 for distributing poisonous liquids in a fine state of division to protect plants 'against 

 parasitic enemies. Largely through the work of this Division, the benefits of this work 

 have been made known and insisted upon, even at times against outspoken and inex- 

 plicable opposition by men holding prominent places among fr\iit-growers and farmers. 

 The only explanation which can be offered is that such opposition was simply a protest 

 against adopting any new method, as a regular part of the annual work, which involves 

 so much extra labour beyond what up to that time had been found necessary. Un- 

 doubtedly one of the most important discoveries which has ever been made in practi- 

 cal entomology and horticulture is the utility of the arsenites as destroyers of leaf- 

 eating insects. This, added to the invention of the spraying nozzle, largely through 

 the skill of Dr. Riley and his assistants in the Division of Entomology of the United 

 States Department of Agriculture at Washington, have provided fruit-growers and 

 others with a reliable remedy, and an implement with w^hich to apply it, in the most 

 economical and at the same time sa'fe manner. Of recent years there have been many 

 variations and some improvements in the remedies suggested for injurious insects, and 

 tdso in the manufacture of spraying pumps and nozzlce^, hut on the whole, if used with 

 proper care, nothing has been yet brought forward of greater general utility and safety 

 than Paris green. Similarly, the Riley Cyclone nozzle, with the Vermorel improvement 

 of a disgorger to clear any obstruction from the orifice, is to-day the best nozzle obtain- 

 able to produce what this operation demands, the breaking up of the liquid to be 

 applied into such a fine state of division as to be an actual spray. It cannot be in- 

 sisted on too strongly that, to get the best results in spraying, such force and such 

 nozzles must be used as will break up the liquid so thoroughly that it falls upon the 

 plants treated as an actual mist. Such terms as 'sprinkling' and 'showering' are 

 inaccurate for the operation here intended. Unfortunately much of the so-called 

 spraying as usually carried out could more accurately be designated by these terms, 

 which describe a much less careful and less even distribution of the liquids, and con- 

 sequently one which is far less effective in attaining the ends aimed at in spraying. 

 The chief factors which affect the utility of spraying as an agricultural and horti- 

 cultural operation are (1) lack of knowledge on the part of the operator as to what is 



