Al'HELEXCIILS PIIVLLOPHAGUS IX CHRYSANTHEMUMS. 235 



^nce of the plants. In no other plants has chenncal treatnrient 

 oi any kind been found of avail, since chemicals of sufficient 

 strength damage the appearance of the plant." Our own limited 

 experience, strange to say, has given quite different results. Mr. 

 Atkin was good enough to expeiiment on some of his plants with 

 the following results : (1) It was found that placing the plant in 

 an atmosphere of carbon bisulphide for as short a period as an 

 hour only produced the death of the plant, and so this method 

 liad to be discarded. 



(2) A spray of dikite potassium sulphide (one ounce to four 

 gallons of water) was found very efficient. K2S, or, as it is some- 

 times known in commerce, " Liver of Sulphur," has long been 

 known as a fungicide in the treatment of rusts, mildew of roses, 

 carnations, etc. It must, however, be employed in vei"y dilute 

 solution, otherwise ill effects appear on account of the 

 sulphuretted hydrogen generated. In the case of chrysanthemums 

 parasitised by Aphdendius, the plants were sprayed once a week, 

 special care being taken to ensure the undersides of the leaves 

 receiving the spray. It is also advisable that the spray be renewed 

 after any heavy rains. In the present instance, chrysanthemums 

 of many varieties, among which were Colonel Appleton, Common- 

 wealth, Mona Davies, Eosy Morn, Thorpe's Beauty, Joseph 

 Stone3% Fred Green and others, were treated and appeared to 

 derive substantial benefit within a very short time. On the other 

 hand, plants whicli were kept as a check or control and remained 

 unsprayed gradually succumbed as a result of defoliation. The 

 ^pray caused no ill effects to the leaves or blooms after treatment. 



Acknowledgment. 



I have much pleasure in thanking the Research Grant Board 

 ior a grant-in-aid for these and other helminthological researches 

 of mine. 



