32 MISSOURI AGRICULTURAL EXPERIMENT STATION BULLETIN 177 



No live scale could be found. 



TABLE 27. PEACHES TREATED IN 1920 



The foregoing tables show that miscible oil does not injure nursery 

 stock to any great extent; however, as compared with the check, some in- 

 jury results from its use. Probably some time is required before the injury 

 shows up to any great extent. At the end of the first two months the per 

 cent of dead plants was not so great where the tops only were treated, as 

 in. the case of the checks. At the end of a year, however, there was about 

 three times as many of the plants, which were treated tops only, dead 

 as in the case of the check. Those plants which were dipped both tops and 

 roots showed a higher percentage of death than those dipped tops only. So 

 it seems that it is not advisable to dip the roots of plants in miscible oil. 



In comparing the two strengths of miscible oil used, the 1 gallon to 12 

 gallons of water, caused a much greater percentage of injury than the 

 weaker strength of 1 gallon of the oil to 15 gallons of water. 



As to the control of San Jose scale, the miscible oil gave excellent 

 results. Both strengths controlled the scale upon the apples. Upon the 

 peach the results were as good with the exception of those treated, tops 

 only, with the 1-12 strength and in this case 99.3 per cent of the scale was 

 killed. 



Taken as a whole, the miscible oil injured the plants less and controlled 

 the San Jose scale better than any of the other materials used. 



As the tables show the lemon oil which was used in 1920 gave very 

 poor results. Lemon oil is used to some extent by florists to spray green 

 house plants which are infested with scale insects, however it seems to be of 

 little value in controlling San Jose scale. 



NICOTINE SULPHATE AS A SPRAY 



In addition to all of the other materials used in 1920 nicotine sulphate, 

 a tobacco extract, was tried. It is a sulphate of nicotine and therefore an 

 acid material. It contains 40 per cent nioctine and is used as a contact 



