POTATO SPRAYING AND DUSTING. 



Table I. 

 Scheme of the Treatment. 







Treatments. 





Locality. 



I. 



IL 



III. 



IV. 



Elmer . . . . Bordeaux and 



1 Lead Arsenate. 



May 21-22. 



KU-Tone. 

 June 1-2. 



Sulphur and 



Lead Arsenate, 



(5--5). 



June 10-11. 



Lead Arsenate. 

 June 24-25. 



Freehold 



Bordeaux and 

 Lead Arsenate. 



May 21-22. 



Ansbacher's 

 Bordeaux- 

 Lead. 



June 17-28. 



Sulphur, Gyp- 

 sum and 



Lead Arsenate 



(2-3-1). 



June 5-6. 



Lead Arsenate. 

 June 16-17. 



Robbinsville 



Bordeaux and 

 Lead Arsenate. 



May 27-28. 



Vreeland's 

 Electro - 

 Bordo-Lead. 

 June 10 11. 



Sulphur and 



Zinc Arsenite 



(5-1). 



June 23-25. 



Gypsum and 



Zinc Arsenite 



(5-1). 



June 30.* 



Discussion of the Individual Experiments. 



At Elmer. From the middle of May until the middle of August there were eleven 

 inches of rainfall, with periods of prolonged drought, during which there was quite 

 a lot of " tip-burn," a physiological condition of the leaves for which no proper reason 

 can be assigned. Probably it is a case of the plant suffering from mal-nutrition 

 as a result of some climatic or atmospheric condition. We cannot say that drought 

 is the only cause, because it has been observed to be prevalent during wet spells. 

 On the 21st May, when the first application was made, the flea-beetle had already 

 been at work for several days, although the foliage was not more than six inches high. 

 The damage being done was considerable, and added to this there were large numbers 

 of eggs of the Colorado beetle on the leaves, some of which had already hatched, 

 betokening injury to come. The plan of the field was as follows : — 



Series I. 

 Bordeaux Mixture and Arsenate of Lead. 

 Arsenate of Lead. 

 Kil-Tone. 

 Arsenate of Lead. 



Sulphur and Lead Arsenate Mixture. 

 Arsenate of Lead. 



* On this date an application of sulphur and zinc arsenite was made on the sulphur 

 plots of the first and second series — there being four series in all at Robbinsville — and 

 on sixteen rows of the third series when an accident rendered the machine useless and so 

 no further spraying was done. At Robbinsville, therefore, with the exception of these 

 plots mentioned, only three applications of the various treatments were made. 



