SPRAYS AND OTHER MEANS OF CONTROL 



1885 



be prescribed together because of oppos- 

 ing medicinal qualities. 



(3) Physically — Not suitable to be 

 mixed on account of liability to produce 

 undesirable physical change. 



In a broad sense, it seems that the 

 word may bo applied to insecticides and 

 fungicides. The distinctions made be- 

 tween the different sorts of incompatibil- 

 ities as applied to pharmacy might also 

 be applied in a general way to spray 

 mixtures. To avoid technicalities, how- 

 ever, it seems best to divide mixtures of 

 insecticides and fungicides into five 

 classes designated by letters. 



CL.1SSIFICATI0\ OF MIXTURES 



The key to classification is briefly given 

 at the bottom of the table for convenient 

 reference. A little fuller statement is de- 

 sirable and is as follows: 



Class A-1 



Compatible. Mixtures in which the 

 chief constituents remain practically un- 

 changed, but are less liable to decomposi- 

 tion after application, or in which an un- 

 desirable constituent has been neutral- 

 ized or rendered less soluble. Mixtures in 

 which the spreading or adhesive quali- 

 ties are improved are also included in 

 this class. 



Class A 



Compatible. Mixtures in which no im- 

 portant chemical or physical changes oc- 

 cur. 



Class B 



Incompatible chemically, but compat- 

 ible in respect to use ('therapeutically" 

 and "physically"). Efficient, non-injuri- 

 ous. 



Mixtures in which important chemical 

 changes occur but the original killing or 

 preventive properties and physical prop- 

 erties are not impaired, and no injurious 

 new compound is formed. 



Class C 



Incompatible chemically, and also in- 

 compatible in respect to use ("thera- 

 peutically" or "physically" or both). In- 

 efficient, non-injurious. 



Mixtures in which important chemical 

 or physical changes occur and render a 

 part or all of the original ingredients 



inert, or less active, or physically unsuit- 

 able for use, but not necessarily injurious 

 to the host of the parasite. 



Class D 



Incompatible chemically, and also in- 

 compatible on account of injurious prop- 

 erties ("therapeutically" or "physically" 

 or both). Dangerous mixtures. 



Mixtures in which important chemical 

 changes occur and render all or a part 

 of the original constituents injurious to 

 the host of the parasite. 



Note — It so happens that D stands for 

 dangerous and the table has been so ar- 

 ranged that dangerous mixtures are thus 

 easily recognized by associating the let- 

 ter which designates the class with the 

 word. 



Interpretation of the Table 



The point must be brought out and 

 strongly emphasized that it is not in- 

 tended to recommend any particular mix- 

 ture shown in the table in preference to 

 any other. That is not the purpose of 

 the table. For example: An A-1 mix- 

 ture is not necessarily a better mixture 

 to use than an A mixture. The compari- 

 son is not between the mixtures them- 

 selves but is intended to be made solely 

 between the mixture and the original in- 

 gredients of the mixture; the classifica- 

 tion is intended to show the effect of mix- 

 ing only. It is seen by looking at the 

 table that a Paris green Bordeaux com- 

 bination is classed as A-1 and a neutral 

 lead arsenate-Bordeaux combination is 

 classed as A. This classification is not 

 intended to mean that the fiirst combina- 

 tion is safer to use than the latter, 

 b\it that the Paris green-Bordeaux 

 combination is safer to use than Paris 

 green alone, and that neither benefit nor 

 harm results from the mixing of neutral 

 lead arsenate and Bordeaux. 



Classification tentative. 



SPllAYLVfi MACHINERY 



W. H. Goodwin 

 Ohio Experiment Station 

 Spraying machinery has become of spe- 

 cial importance during recent years 

 through the interest in fruit growing 

 aroused among farmers and fruit grow- 

 ers in general. 



