24 



there were nuinennis galls. Some further exi)eriments were 

 made along similar lines which showed the injurious influence 

 of w^ater on eel worms. Dr. li. E. Bessey, of the United States 

 Department of Agriculture, recently informed us that he had 

 observed the same thing in the South along river banks where 

 the soil is inundated for a certain length of time each year. 

 The application of excessive amounts of water to the soil for 

 brief periods of time might j^rove a practical method of ridding 

 soil of this pest. 



Parasitic eel worms are not indigcnrms to this region on 

 account of our severe winters, and infection comes about largely 

 from the use of manures containing refuse in which eel worms 

 are present. 



If once thoroughly eradicated from a greenhouse, precautions 

 sliould ]je taken in regard to the introduction of manures or soils 

 contaminated with eel worms, as well as j)lants from infested 

 houses. 



Florists frequently make use of liquid decoctions of manure 

 in feeding their plants, and since eel worms are destroyed by 

 water, this practice shf^uld cause little trouble. 



SURFACE MOLDS 



(White Fly Excretions.) 



Tftniatoes under glass suffer to a considerable extent from 

 the excretions of the greenhouse white fly (Aleyrodes). When 

 this fly becomes abundant and is allowed to thrive in tlie hcjuse 

 the plants become coated with a sticky substance (honey-dew), 

 which f<jrms a favorable medium for the develoj^ment of surface 

 molds which cover a considerable part of the foliage and cause 

 much injury to the ])lant in one way or another. The remedy 

 is oljviously to destroy the flies. 



h'ollowing the advice of Dr. H. T. Fernald, entomologist to 

 the Station, we have used hydrocyanic acid gas successfully for 

 white flies. The following formula has been used repeatedly 

 by us without ajjpreciable injury to the ])lants, and we succeeded 

 in destroying all the flies. 



10 gms.* fused cyanide of potassium (UH-^}U% pure). 



2i) c. c. commercial sul])huric acid. 



iO c. c. of water lo l.DDO cubic feet of space. 



Turn the acid into the water in an earthen or graniteware jar 

 and then, Ijy a loose bag and string, drop the cyanide in, after 

 tightly closing the place to be fumigated. 



*28 gms. eciual 1 oz. 



