210 BULLETIN NO. 62. 



conducted in Ohio by Mr. A. F, Burgess. It is a well known fact 

 that the codling moth hibernates as a larva enclosed in a cocoon. 

 Mr. Burgess finding many larvae in their winter quarters in a fruit 

 house in Deleware, Ohio, took advantage of the opportunity to ex- 

 periment with the use of hydrocyanic-acid gas as a means of killing 

 the insect in this stage. The formula used was one ounce potas- 

 sium cyanide of 98 percent purity, one fluid ounce of sulphuric acid 

 and three fluid ounces of water to each ico cubic feet of enclosed 

 space. After tightly closing the house the gas was liberated at 

 3 :oo p. m. and the door was opened at the expiration of 20 minutes. 

 Without going into details the general results of the experiment 

 was that about 40 percent of the larvae were found to be dead 

 about two weeks after the fumigation. Considering the fact that 

 the house was well constructed and the experiment carefully made 

 it seems to be well shown that this treatment cannot be depended 

 upon for killing the hibernating larvae of the codling moth. The 

 use of this gas in fruit houses after the weather has become warm 

 in the spring of the year so that the moths are flying about th<-; 

 house, may reasonably be depended upon to kill this insect in the 

 moth stage. It is essential however, that the house be of tight 

 construction in order to prevent the escape of the gas. 



TREATMENT REQUIRED BY OLD ORCHARDS. 



Old neglected orchards are a mepace to the fruit industry for 

 they harbor insect pests in abundance. Almost every apple pru- 

 mav contain a worm. .Beside being left unsprayed the trees 

 of such an orchard may have many scales of bark which offer 

 excellent hibernating quarters. Such trees should either be cut 

 down and burned or brought into condition to produce clean fruit. 

 To recover such trees they should be pruned, the holes should be 

 filled with cement or plaster, and the rough bark removed and burn- 

 ed. Then the trees should be sprayed as in young bearing orchards. 

 As strange as it may seem we are already getting orchards and 

 trees of this description in Montana. Owners not realizing their 

 early hopes from their trees have turned their attention to other 

 things and have neglected the earlier enterprise. The existence 

 of such trees should not be tolerated by the owner of the premises 

 ■or by public sentiment. 



