June, '19] GOODWIN: JAPANESE FLOWER BEETLE 251 



This made them ahnost impossible to find after they had eaten leaves 

 of the dusted food plants. 



Hand collecting was practiced throughout the season from July 1 

 to mid-September. Average catches for the day varied with the 

 locality collected and with weather conditions. Collections made 

 largely after 6.30 p. m. from July 5 to July 20 by Mr. Perry and myself 

 totalled almost fifty quarts. Collections by the boys employed for 

 this purpose and under Mr. Spayd's direction varied considerably, 

 but the total season's catch was a little over four bushels of beetles. 

 Counts of measured quarts ranged from 4,400 to 5,000 beetles to 

 the quart or 150,000 to the bushel. 



Fall treatment of the soil to destroy the larvae by using cyanide of a 

 strength of 1 ounce of NaCN in 12 gallons of water began the 16th of 

 September, using the Ford and 100 gallon gasoline tank. Some 

 momentous events happened preventing me from being on the ground 

 during October excepting for a few days during the latter part of the 

 month. Under Dr. Headlee's general direction Mr. W. O. Ellis took 

 charge of the eradication work during my absence. A two-ton truck 

 which had been wanted since June 1 arrived during October and a 600- 

 gallon tank was secured and mounted on it, enabling the treating of 

 one-third to one-half acre of land per day with sodium cyanide solution 

 with this outfit. A street-sprinkling outfit was hired and the tractor 

 and sprayer truck and tank was also put into service enabling the 

 treating of three-fourths to one acre per day with the entire equipment. 



Approximately seventeen acres of land was treated with the solution 

 of sodium cyanide applying 15,000 to 25,000 gallons to the acre. 



This includes the sod or grassy edges of drives, along roads, ditches, 

 and several small fields of corn ground and grass land. 



Normal rates of applying this sodium cyanide solution would require 

 110 pounds of sodium cyanide to the acre. Some territory treated 

 this fall undoubtedly did not receive much over half of this amount per 

 acre as the failure to get a kill on some fields indicated. A total of 

 eleven acres should have used our entire stock of sodium cyanide, while 

 between sixteen and seventeen acres were treated. 



During the latter part of November, we borrowed a gang plow, 

 hitched it to the tractor and plowed between seven and eight acres of 

 land heavily infested with larvae to determine if possible the effect of 

 such treatment on the larvae. These plots of land are of several differ- 

 ent types of soil and had been cropped in clover, grass, rye, corn, 

 parsley, weeds, and sod along ditches. Most of the ground was plowed 

 8 inches deep, but some small plots were plowed 12 to 14 inches deep. 

 The 12-20 tractor handled the plows at this depth after four months of 

 continuous service in this sandy region. Without this machine we 



