18 FAEMEES' BULLETIN 799. 



growers who li;ne tested it thoroughly ch^im that it will work in 

 either clay or sanely soil, and that it destroj^s both maggots and pupae. 

 In appljdng the disulphid for root-maggots the dose is distributed 

 in one or two holes made not nearer than about 4 inches from the 

 base of the plant and running down to a point a little below the 

 roots. The holes must be closed tightly with earth and compacted 

 by pressure with the foot. The dose A^aries from 1 teaspoonful for 

 each small plant to a tablespoonful for large plants.^ One injection 

 should be sufficient if made in time, but if delayed too long nothing 

 can save the plants. 



TREATMENT FOR APHIDS ON LOW-GROWING PLANTS. 



Aphids frequentlj^ become extremely abundant upon melon, cit- 

 ron, and other cucurbit vines and upon young cabbage plants, etc. 

 Here thej' are very hard to control by spraying with contact insecti- 

 cides because of the curling of the leaves. Carbon disulphid has 

 been used successfullj^ for the control of melon aphids by evapo- 

 rating the liquid under a tub which covers the vines. Another form 

 of covering used for the plants is a box made of a light frame of 

 wood about 24 inches square by 8 inches high, covered with closeh' 

 woven muslin cloth which is soaked with linseed oil and then dried 

 to make it gas-tight. The cloth is made to project some 6 or 8 inches 

 beyond the frame so as to form a loose flap around the outside upon 

 which dirt can be piled to make the covering fit tightly to the 

 ground. These boxes are light, durable, and convenient to handle. 



The dose consists of 1 teaspoonful (1 dram) of liquid to a plant, 

 or for a box containing about 1 cubic foot, and should be increased 

 proportionately with larger boxes. If the receptacle is of irregular 

 shape, but water-tight, the contents may be determined very accu- 

 rately by filling it with water. It takes very nearly 7^ gallons (30 

 quarts) of water to fill 1 cubic foot of sjiace. 



The liquid may be evaporated from a shallow dish, or arrange- 

 ment may be made so that the liquid can be poured through a large 

 hole in the top of the box into some absorbent material fastened 

 permanently beneath it, and the hole then closed tightly with a stop- 

 per. On account of the small space that is being treated, special 

 care should be taken to measure the amount of liquid accurately. 

 The covers should remain in place for one hour and then be moved 

 to fresh plants. With from 50 to 100 boxes, a field may be treated 

 with comparative rapiditj'-, and the vapor will reach the aphids much 

 more thoroughly than if applied in any other way. Plants will be 

 more resistant to the vapor at night, when the breathing pores 

 (stomata) are closed. 



' Four teaspoonfuls are approximately 1 tablet<poouful, and 2 tablespoon fuls are ap- 

 proximately 1 fluid ounce. 



