June, '22] weigel & douchette: strawberry root worm on roses 207 



terials was tested in these pots, observations being taken either five 

 or ten days after treatment: 



Paradichlorobenzene — 2 gms. to 8 gms. per plant. 

 Borax — 1 gm. and 2 gms. in solution per plant. 

 Sodium cyanide — 0.45 gms. to 1.77 gms. in solution per plant. 

 Orthodichlorobenzene — 3 cc. per plant. 



Mercuric chloride — (rate of yi. ounce per 3 gallons water, yi pint per plant). 

 Kerosene nicotine oleate emulsion (1 part to 16 parts water; 1 part to 32 parts 

 water per plant). 



Wood ashes — handful at base of each plant. 

 Tobacco dust — handful at base of each plant. 

 Lye — -one teaspoonful per plant. 

 Nicotine Sulfate — 2 drops in 225cc water per plant. 



Of these materials Paradichlorobenzene, Orthodichlorobenzene, Sodium 

 cyanite and Kerosene Nicotine Oleate em.ulsion gave promising indica- 

 tions. 



With this as a basis a total of thirty-eight plot experiments were then 

 conducted on the infested bed using from five to twenty-five plants 

 in each test. Examinations of the treated as well as the check plants 

 were made at as close to five day intervals as conditions would permit 

 by digging up the plants and examining the roots and surrounding soil 

 for the larvae and pupae present. In this manner, observations were 

 made on the effectiveness of the materials used as well as the minimum 

 time which was required for them to exert their insecticidal action. 

 The following materials were used: 



Paradichlorobenzene was employed in fourteen tests in amounts 

 ranging from five grams to one-half ounce per plant. 



vSodium cyanide was tested in nine plots, using from one-half to five 

 grams dissolved in about one pint of water and poured around the 

 base of each plant. The same material in the dry form was applied 

 at the rates of two, three, and five grams per plant, respectively. 



Kerosene nicotine oleate emulsion in dilutions varying from one- 

 fourth pint to one pint per gallon of water was used in five tests. 



Orthodichlorobenzene was given three trials of Ice, 2cc., 3cc., per plant 

 respectively, applied directly at the base of the plants. 



One-half ounce mercuric chloride dissolved in three gallons water, 

 as well as tobacco dust, wood ashes, and a combination of the two, 

 were also tested. 



Results : Tobacco dust and wood ashes, alone and combined gave 

 encouraging indications but as they are now being tried out on a com- 

 mercial scale further comment is reserved. Mercuric chloride proved 

 entirely valueless. While orthodichlorobenzene trials produced a mor- 



