white; grubs and juni^ be;e;tles. 28 



reached perfectly definite conclusions, they recommend the fol- 

 lowing treatment for potatoes in bins. 



The bin or room where the potatoes are stored should be 

 closed as tightly as possible. Ten ounces of formalin should 

 be used for every 1,000 cubic feet of room, and the potatoes 

 should be left exposed to this gas for 24 hours. The gas is 

 generated by the action of formalin upon potassium perman- 

 ganate. For this purpose 3 parts by weight of potassium per- 

 manganate are mixed with 8 parts of formalin in an earthen 

 jar. The jar should have a capacity of about a gallon for each 

 pint (16 ounces) formalin. The required amount of perman- 

 ganate should be placed in the bottom of the jar, and the needed 

 amount of formalin poured over it. The operator should leave 

 the room at once, taking care to close the door as tightly as 

 possible. The retail cost of the chemicals to produce gas for 

 1,000 cubic feet will be about $1.50. 



For handlers of seed who wish to insure freedom from scab 

 and for large growers of potatoes, this gaseous method is more 

 convenient than the wet method, and experiments at the Ver- 

 mont Station show it to be effective. 



WHITE GRUBS AND JUNE BEETLES.^ 



The large brown June beetle commonly buzzing and bump- 

 ing about lights at night, and the lar\^a of this beetle (the 

 white grub) so frequently turned up from the soil by the plow 

 are both too well known to need description. The accom- 

 panying figures 24 and 25 illustrate both stages of this insect. 



The June Beetle. In the spring the fully developed beetles 

 emerge from the ground where they have passed their larval 

 stage. During the day they remain quiet but at night they 

 congregate upon willow, cherry, plum and other trees to devour 

 the leaves. These beetles deposit their eggs usually in grass 

 lands. 



* Seven or more closely related species, formerly clrtss.eil as Lachnosterna fusca, 

 are now called ihu /unca group. Tbese with many other species are confused 

 under the name of June beetle, May beetlp, or Dnrbug, and the larvae of them all 

 are sufficiently alike to permit them to be classed no one for economical treat- 

 ment. 



