88 JOUKNAL OF THE EOYAL HOETICULTURAL SOCIETY. 



or late in the autumn after the function of the foliage has been per- 

 formed. Fig. 19 shows an outfit at work October 26, 1900, at which 

 time the trees had no further use for the leaves. No burning of the 

 foliage was noticed on these trees, where the exposure was not greater 

 than thirty minutes and gas generated from the 0*20 gramme formula. I 

 do not advise the fumigation of trees in mid-summer or during the grow- 

 ing period. If it is found necessary to apply the gas during the summer 

 months, it should be done at night. In California, large orange orchards 

 are fumigated when in full fruit at night to avoid burning the foliage. 



This method is not easily applied to very large fruit trees, but it 

 seems to be the coming remedy for younger trees, especially those under 

 10 ft. in height, in orchards where the Scale has established itself. The 

 work is quickly done and the cost of the equipment is not necessarily 

 very great. A large Emory fumigator with hood will cost from £2 10s. to 

 £S, while the rigging necessary for handling it costs about an equal 

 amount. 



