INSECTS 45 



the sun retards through September and October. During these eras nightly 

 fumigations, or at least every other night, should be continued to keep 

 them under control. 



It has been determined the fly emerges from the gall after midnight 

 and doubtless fumigations between that time and morning would be most 

 effective. We have been able to keep well under control by fumigation at 

 6 p. m. every night, using Tobacco paper and Cyanide alternately. In 

 using Tobacco paper occasionally the thrips, which are a serious Chrysan- 

 themum pest when they get a foothold, are easily subdued. 



Recent investigations have demonstrated that spraying the plants with 

 nicotine sulphate 40% one part to five hundred parts of water, with the 

 addition of one ounce to the gallon of Fish-oil Soap, will kill the emerg- 

 ing adults and a large percentage of the eggs, but the operation should be 

 repeated four or five days. This method may be very useful where a small 

 Lumber of plants are grown and possibly be less expensive, but in larger 

 establishments where there is considerable space to be treated, fumigation 

 is undoubtedly the most practical owing to the saving in labor and the 

 probability that infested parts might not be reached by the spray. It may 

 also be very useful in localities where Chrysanthemums are grown out of 

 doors. 



To the Chrysanthemum grower the serious part of this question is the 

 improbability of ever being entirely free of this intruder. No one is im- 

 mune as long as new stock is purchased and it behooves every one inter- 

 ested in this class of plants to do their part in an endeavor to keep them 

 under control. We occasionally buy plants that are apparently clean, but 

 on the other hand a greater part are more or less -affected. 



We prefer Cyanide to tobacco fumigation, being more powerful and 

 lasting in its effect. There are two forms of Cyanide, the potassium and 

 the sodium, both are deadly poison, either in the crystal or liquid form, 

 ,'i.-; well as the gas emitted when brought in contact with sulphuric acid. . 

 The highest grades of Cyanide are the best for this purpose and as 100 

 parts of Sodium Cyanide are as efficient as 129 parts of Potassium Cyanide, 

 we prefer the former. Since the publication of third edition Sodium Cyan- 

 ide has been placed upon the market in form of an egg is known as Cy- 

 anegg and these pieces do not vary far from 1 oz. each. When purchased 

 ii: this form it eliminates the necessity of weighing out the amount for 

 (ach jar. 



The quantity used is based upon the cubic contents of the house, which 

 is practically 1 oz. to each G,000 cubic feet. A house 30x100 feet with aver- 

 age height of 8 feet will contain 24,000 cubic feet of space. 



For such a house we use four small stone jars and prefer such as hold 

 only 8 to 10 ounces (dishes used for baking beans, known as individual 

 bean dishes, are very serviceable) rather than larger ones, as they are 

 easier handled and more convenient. 



Use a stone jar of sufficient capacity to fill the necessary number of 

 jars and figure 3 ounces of acid solution to the jar. To prepare this solu- 

 tion put parts of water in the jar and add 2 parts of commercial sulphuric 



