August, '21] CORY: A NEW INSECTICIDE 347 



killed. The native rose slug was sprayed out doors on May 18th with 

 a dilution of 1-600 with practically 100% control. Almost full grown 

 larvae of the currant worm were sprayed in the laboratory on May 19th 

 w4th dilutions of 1-500, 1-600. 1-700, 1-800, 1-900 and 1-1000. Tak- 

 a-nap soap was used with similar dilutions at the rate of 4 pounds to 

 50 gallons. Fourteen lots of 10 larvae were sprayed resulting in an 

 average of 66% killed. Very little difference between the weaker and 

 stronger solutions with or without soap prevailed. 



Tests As A Stomach Pojson And As A Repellent 



The work with the tent caterpillars gave us notes on its effect as a 

 stomach poison and as a repellent. In the laboratory tests with the 

 tent caterpillars, leaves of the wild choke cherry were dipped or sprayed 

 in dilutions ranging from 1-100 to 1-200, allowed to dry from 2 to 4 hours 

 and then placed in vials of water under lantern globe cages or small 

 screen inclosures. Ten lars^ae were then introduced in each cage; 25 

 test lots and 5 check lots. In all cases the larvae refused at first to 

 stay on the treated leaves. There was a shrinking of the body and an 

 inactivity on the part of the larvae resulting from confinement with 

 the leaves. Approximately 50% died after a lapse of 5 to 10 days. 

 This indicates a decided repellent and possible toxic action. In one 

 of the large cages though there was plenty of circulation of air, a num- 

 ber of dead and dying larvae were found on the bottom of the cage 

 after they had fed upon the sprayed leaves. In many of the smaller 

 cages, the larvae refused to feed and it is possible that the fumes were 

 the cause of the disinclination to feed. From these experiments we 

 were unable to determine whether the material acted as a stomach poi- 

 son or a contact insecticide, partly due to the type of cage used, the 

 general inactivity of the larvae and the fact that little eating was done 

 even by those in the check cages, in one set of experiments. 



vSUMMARY 



Tests indicate that the material has a decided effect as a contact in- 

 secticide, repelling powers to a considerable degree and a possible toxic 

 action . 



In no instance did the material injure the foHage or spot the most 

 delicate flowers. 



The field for the use of this material in green -houses, on flowers and 

 ornamentals and in home gardens seems to be promising. Its appli- 

 cation to the contr3l of insects affecting forage, that cannot be sprayed 

 with an arsenical, offers another possibility. 



