EMULSIONS FOR JAPANESE BEETUE 15 



APPLICATION OF CARBON-DISULFIDE EMULSION TO LARV^J AND 



PEONIES 



Larvse were placed in the cavities of the peony roots and the 

 cavities then filled and plugged "with soil. The plants thus arti- 

 ficially infested were dipped in various dilutions of the carbon- 

 disulfide emulsion for various periods of time but always at a 

 temperature of 70° F. Forty-eight hours after removal from the dip 

 the larvse were taken from the root cavities and the mortality deter- 

 mined; the plants themselves were set out in the nursery row and 

 kept under observation for possible injury to the buds and rootstocks. 

 This test is of interest in connection with the treatment of plants for 

 the fall and spring shipping seasons. 



Three series of treatments were tried, each series with a particular 

 strength of solution and varying periods of time. For the first, a dip of 

 4.2 cubic centimeters of emulsion 1, and one of 4.5 cubic centimeters 

 of emulsion 2, to 6 liters of water, the two considered as of equal 

 strength, were used, and peony roots infested as just described im- 

 mersed in one or the other solution for 6, 9, 12, 15, 18, and 24 hours, 

 respectively. Plants containing in all four larvse were submerged 

 for each of the periods named. The peonies were uninjured by the 

 treatment except that the bud scales were blackened by the 24-hour 

 exposure. All the larvse exposed for 12 to 24 hours, inclusive, were 

 killed ; for each of the other two treatments but one larva was killed, 

 the other three coming out alive. 



Dips were tried of twice the strength, 8.4 cubic centimeters of 

 emulsion 1 and 9.14 cubic centimeters of emulsion 2, each to 6 liters 

 of water, with immersions of 6, 12, 18, and 24 hours, respectively, 

 four larvae with the plants containing them being used in each case. 

 All the larvse were killed. The peonies were badly checked by the 

 shortest exposure and killed by all the others. 



The strength of dip was again doubled, 16.8 cubic centimeters 

 of emulsion 1 and 18.28 cubic centimeters of emulsion 2, each to 6 

 liters of water being used. Four larvae, with the plants containing 

 them, were immersed as before for the several periods of 6, 12, 18, 

 and 24 hours. In all cases plants and larvse were killed. 



COMMERCIAL USE OP EMULSIONS 



In treating peony, iris, phlox, and sedum plants infested with 

 Popillia larvse the writers have found it best to pack the plants in 

 tubs until nearly level with the top. Galvanized-iron tubs are best 

 for this purpose since they rarely leak, as is the case with wooden 

 tubs, and they do not absorb the toxic material from the dip. 



In cold weather the plants should be allowed to warm up for 24 

 hours in a room kept at a temperature of 70° F. before being dipped, 

 and the actual dipping should be performed in a room maintained 

 at this temperature. 



The water for the dip should be brought to a temperature of 75° F. 

 In our experience, extra tubs are best for this purpose. When the 

 water is heated to 75° F., stir in the required amount of emulsion 

 and pour the mixture into the tubs containing the plants, being sure 

 that all the plants are submerged. 



The dosage and period of submergence for the various plants are 

 as follows: 



Japanese /'/is-.— Dosage, 1 cubic centimeter ascaridole to liters 

 of water. Allow plants to remain submerged for 15 hours. 



