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N. S. ENTOMOLOGICAL SOCIETY. 



aged 34 apples each when picked, while the trees sprayed with lime and sulphur gave 

 but 6 apples on the four trees or an average of 1| apples per tree. 



These two tests, corroborating the assertion of many of the most reliable growers, 

 indicated that a great amount of damage was being done by lime sulphur in the ordin- 

 ary strengths in removing the apples from the trees. Just at what strength the lime 

 sulphur began to burn was not determined, nor just when the greatest injury occurred, 

 but the Thomson orchard indicated that the fruit was most susceptible to injury about 

 two weeks after the blossoms. 



In 1916 the young Wagner orchard already mentioned was secured in order to fully 

 test out the points in question. 



The first experiment was arranged to determine the strength at which the ordinary 

 lime sulphur solution burned and at what strength it began to remove apples from the 

 trees. A number of young Wagner apple trees of even size and bearing as nearly as 

 possible an even bloom were selected. They were sprayed three times, once immediate- 

 ly before the blossoms, once immediately after the blossoms and once two weeks after 

 the blossoms, with strengths of lime sulphur varying from 1.004 sp. gr., or 1 gallon of 

 concentrated commercial lime sulphur to 75 gals of water to 1.010 sp. gr. or one gal. con- 

 centrated commercial lime sulphur to 30 gals of water. Paste (acid) arsenate of lead 

 was used in one series and arsenate of lime (44 per cent arsenic oxide) was used in the 

 other. The following table shows the number of apples matured on each pair of Wag- 

 ner apple trees with the different strengths of solution. The unsprayed trees averaged 

 277 apples per pair of trees. 



No. of Apples Matured per pair of Wagner Trees. 



These results show that lime sulphur used 1.007 sp. gr. or one gallon of com- 

 mercial concentrate to 43 of water and stronger, with arsenate of lead causes serious re- 

 duction in the number of apples picked. Where arsenate of lime was used the lime sul- 

 phur, 1.008 sp. gr., or one gallon of commercial concentrate to 37§ gals of water and 

 stronger, caused some reduction in the number of apples picked, but not so great a re- 

 duction as in the corresponding strengths where arsenate of lead was used. 



It will be noted from the table that in all cases the trees sprayed with even the 

 most dilute solutions of lime sulphur gave fewer apples than the unsprayed trees. The 

 trees were sprayed with a coarse driving spray throughout and heavily drenched. 

 The fruit from the unsprayed trees was almost worthless on account of insect injury and 

 fungous disease, so these results do not constitute any argument against spraying but 

 rather they indicate the desirability of more dilute solutions of lime sulphur and the fur- 

 ther investigation of the material with the idea of rendering it more harmless. 



