236 INSECTS INJURIOUS TO STAPLE CROPS. 



of water is strong enough if properly applied, and in no 

 case should it be used stronger than one pound to 125 

 gallons. The best way of applying the mixture is by 

 means of a knapsack-pump, and both surfaces of the leaves 

 should be sprayed. 



Florida growers have used the arsenite of lead to some 

 extent, dusting it on the plants dry, by means of a bellows 

 or powder-gun, such as is manufactured by Leggett Bros. , 

 301 Pearl St., New York. It is a white powder, more 

 insoluble than Paris green, but it will not burn the foliage 

 as readily. It is also more adhesive when thus applied, 

 remaining on the foliage for eight or ten days. 



A method for killing the adult moths has been satisfac- 

 torily practiced for many years. It consists in poisoning 

 the flowers of the Jamestown weed [Datura stramonium) 

 with a sweetened cobalt solution. The flowers are placed 

 around the fields in the evening, being set upright in holes 

 of horizontal slats, or supported by sticks. The cobalt 

 solution is then introduced into them by means of a quill. 

 It is composed of — cobalt, one ounce; molasses, one-fourth 

 of a pint; water, one pint. In their search for flowers 

 the moths will be attracted by the odor of the molasses and 

 the cobalt of the solution will poison them, and thus jore- 

 vent the females from laying some two hundred eggs 

 toward another brood. 



Enemies. — There are also several insects which tend to 

 keep this pest in check by parasitizing it, and about which 

 many growers do not seem to be well informed. Worms 

 covered with what seem to be small white eggs are ahvays 

 common. They are not eggs, however, but the cocoons 

 of a small hymenopterous insect whose larv« feed upon 

 tlie worm internally and thus ultimately kill it before it 



