Proceedings, 1923 



minnows, which winikl iiuitcrially reduee the costs of oilin<>- operations. 

 Experiment.s have also been projected to test oiit the comparative values 

 of oils, larvicides, etc., and their adaptability to the needs of the district. 



It is lio])ed that at the conclusion of these investio'ations mostpiito 

 control at Banff will have been placed on a fairly sound scientific basis, 

 and tliat freedom from the mosquito nuisaiu'e will be possilile with the 

 R-reatest (»conorav in labour and materials. 



THE STATUS OF SPREADERS IN THE POISON SPRAY SOLUTION 



IJV A. L. LdVKTT. EXTdJKlLCKilST, 



Oregon Agrutltt-ral Experimext Station 



Commercially prepared spreaders were used rather extensively in 

 orchard spraying for the first time this past season. The interest mani- 

 fested in this recent innovation in our spray practices makes it appear 

 desirable to undertake a ^enei-al survey of the situation, attempting- to 

 develop a summary of the opinion.?, observations, experiments and re- 

 actions of the growers, experimentors and others following the close of 

 the year's trial of the use of spreaders. 



Historical 



The addition of materials to the spray solution for the impro^-ement 

 of its physical properties is by no means new. Various materials, in- 

 cluding glue, molasses, soap, saponin, casein, gelatine, aluminum sul- 

 ]ih;ite, etc., have been added as spreaders from time to time where the 

 investigator, dealing with a specific pest or disease, appreciated the 

 desirability of improving the wetting and adhering jn-operties of the 

 spray solution. 



Probably the first large scale investigation of spreadei's for use with 

 poison sprays, having a rather definite application to the economic control 

 of orchard pests, were tliose undertaken Ijy the Oregon Experiment 

 Station. A variety of materials were tested as spreaders ; among the 

 more promising were caseinate, glue, gelatine, saponin and mineral 

 oil emulsions. In considering their qualities as a spreader, the following 

 factors were necessarily taken into account: (1) Availabi.lity, (is the 

 source of supply easily accessible and adequate?) ; (2) Compatibility, (the 

 spreader must not react unfavorably with any ordinary spray water, 

 spray material or combination of spray materials) ; (3) Efficacy, (in 

 reasonable amounts they must actually give satisfactory results in in- 

 creased wetting, adherence, etc.) ; (4) Ease in preparation, (complicated 

 manipulations, cooking; any operation requiring close attention or much 

 additional work meets little favor with the grower) : (;j) Cost, (must 

 be reasonable in price). 



