AUGUST, '21] CORY; A NEW INSECTICIDE 345 



SOME NOTES ON A NEW AND PROMISING INSECTICIDE^ 

 By Ernest N. Cory, College Park, Md. 



Routine tests of a new insecticide about to be put on the market by 

 McCormick & Company, Baltimore, Maryland, developed the fact 

 that the material has considerable promise, particularly, in certain 

 fields. 



The insecticide is an alcoholic extract of pyrethrum prepared in the 

 form of a hea\'A- liquid soap. It mixes readily with water at any de- 

 sired strength, spreads evenly and sticks fairly well. 



Tests were conducted to determine its efficiency as a contact spray, 

 as a repellent and as a stomach poison. Whether the efficiency could 

 be increased by the addition of more soap was tested and the effect of 

 the spray on foliage and flowers was carefully noted. 



The following insects were used : the egg plant lace bug {Gargaphia 

 solanii Heid.); two species of rose slugs {Cladius pectinicornis Fourer 

 and Endelomyia rosae Harr.); the mealy bug (Pseudococcus ainRisso.); 

 plant lice on nasturtium (Aphis rumicis Linn.); the chrysanthemum 

 Q.'phi's, {Macrosiphum sanborni Gill.); an undetermined aphid on Jap- 

 anese Barberry, the eggs of the imported cabbage worm {Pontia rapae 

 Linn.); the imported currant worm (Pteronus rihesii Scop.); and the 

 tent caterpillar (Malacosonia americana Fabr.). 



Tests As A Contact Insecticide 



Tests against the egg plant lace bug in the field were inconclusive, 

 therefore, further tests were made on large pieces of infested plants 

 placed in water in the green-house. These plants were sprayed Oct. 

 5th with a dilution of 1 to 300. After 24 hours 50% were dead and 

 the balance showed feeble movements. Most of the latter had left the 

 plant and were lying feet upwards on the floor of the cage. All finally 

 died after a lapse of 48 hours. 



Rose aphids on the tips of roses in the green-house were sprayed 

 Oct. 1st. and March 12th. The first application was made at a dilu- 



'Contribution from the Entomological Laboratory - Maryland Agricultural Ex- 

 periment Station. December 20, 1920. 



