22 MISSOURI AGRICULTURAL EXPERIMENT STATION BULLETIN 177 



TABLE 11. PEACHES TREATED IN 1916 



The results obtained on the peach also show that carbon bisulphide 

 will not entirely control San Jose scale when used at the rate of 1% to 100. 

 However, these results are much better than those obtained upon the apple 

 which is probably due to the fact that most of the heavily infested peach 

 trees died, which made it impossible to get as good a count. The peaches 

 that lived were not so heavily infested. 



TABLE 12. PEACHES TREATED IN 1917 



No live scale could be found upon the peach trees treated which was 

 probably due to the fact that as a result of the treatment practically all of 

 the young tender growth, which was the most heavily infested part of the 

 trees, had died. 



It will also be noticed that a larger per cent of the plants treated wet 

 died, both at the end of the second month and at the end of the first year. 

 However, the difference was not very great. With hydrocyanic-acid gas 

 more of the plants treated dry died. It may be that carbon bisulphide has 

 an altogether different physiological effect upon the plant, especially in the 

 presence of moisture. A larger percentage of the scale on the trees treated 

 wet were killed which seems to further indicate that carbon bisulphide 

 used in the presence of moisture is more active. 



Owing to the fact that carbon bisulphide did not in any case completely 

 control the San Jose scale upon apple trees, and in only five out of six 

 cases upon the peach, and since the percentage of injury to the plants was 

 very great, its use as a fumigating material upon nursery stock should be 

 discouraged. 



