640 -' EXPERIMENTAL FARMS 



7 GEORGE V, A. 1917 



some gasoline to be put on the top of them at lighting time, an.d as the gasoline is put 

 in the self-lighters at filling time, it may be evaporated before a frosty night occurs, 

 thus, although the cover may fly off and the wick be lighted, the flame will be extin- 

 guished when it falls into the oil. These two objectionable features rendered the 

 heaters unreliable, although on numeTous occasions they worked all right. As yet, 

 however, they cannot be recommended for general use. 



A CHEAP FROST ALARM. 



In previous reports, attention has been called to a frost alarm thermometer, 

 costing about twenty or twenty-five dollars. This last year a much cheaper, but still 

 reliable, alarm was tested. This new alarm costs not more than four dollars and con- 

 sists of a metal diaphragm, which expands or contracts according to the changes in 

 temperature. This may be so set as to ring a bell at any temperature by means of a 

 small battery which is attached to the alarm. This alarm, comes in two pieces, one 

 piece being the sensitive diaphragm and the other the bell and battery box. 



From our experience, this is quite reliable and on account of its low cost should 

 form a part of every frost fighter's equipmqnt. 



SPRAYING. 



EXPERIMENTS. 



A large part of the orchard was devoted to a comparative test of several different 

 spray mixtures as regards foliage injury only, it being impossible to report on scab 

 control as there is practically no scab at present at Ottawa during most seasons. 



The object of the test was to compare the relative values of Bordeaux mixture, 

 lime sulphur and soluble sulphur. Plots Nos. 1, 2, and 3 were sprayed with soluble 

 sulphur on May 7, June 4, June 24 and July 7, while plot No. 4 was sprayed on the 

 last three dates only. The remaining plots were sprayed only once, viz., on July 12. 

 To determine the effect of the different mixtures on the foliage, large quantities of 

 leaves were gathered from the different plots and divided into slightly injured, badly 

 injured and no injury groups. These were all counted and a result of this count is 

 given in the attached plan. It may be added that the leaves were gathered by a 

 person who only knew the location of the plots and their number, but did not know 

 how each plot had been treated. In this way an unbiased estimate should result. 



The conclusions from these results would indicate that soluble sulphur without 

 the addition of arsenate of lead is non-injurious to the foliage or practically so, there 

 being only 4i per cent injury and that only slight. On the other hand, as soon as 

 lead arsenate is added the results show a very serious burning, as will be seen by 

 examining the record of plots Nos. 1 and No. 2, also plots Nos. 7, 11, 12 and 14. An 

 examination of these plots will also show that either an increase of lead or an increase 

 in the strength of the soluble sulphur will cause an increase in the burning. The 

 burning in every case where soluble sulphur and arsenate of lead were combined was 

 serious, and it is safe to say that these two preparations cannot be used together 

 without the risk of obtaining serious results. 



Comparing this with lime sulphur and lead arsenate, it will be seen that the 

 burning in the case of lime sulphur was mostly slight and that even then the total 

 injury Avas much less than in the case of the soluble sulphur-arsenate mixture. Bor- 

 deaux mixture gave the least injury of any of these mixtures, but possesses very 

 slight advantage over lime sulphur in this respect. Of course, in different seasons 

 the amount of injury from Bordeaux and lime sulphur varies as might perhaps the 



Ottawa. 



