388 Report op the Horticulturist. 



two hundred gallons is commonly used. For stone fruits the 

 mixture should be weaker, using one pound of Paris green to two 

 hundred and fifty or three hundred gallons. When used with 

 water, fresh slaked lime should be added to prevent injury to the 

 foliage. Smith,^^ in 1892, recommended an equal weight, while 

 Sirrine, in Bulletin 83 of this Station, recommends sixteen times 

 as much fresh slaked lime by weight, as Paris green, for the purpose 

 not only of preventing injury to the foliage by the Paris green, but 

 also to make it stick to the foliage more firmly. 



Tobacco. — This is frequently used in greenhouses, and some- 

 times in gardens in the form of tobacco dust, against soft bodied 

 insects like plant lice. The plants are dusted thoroughly with it on 

 the first appearence of the insects and before they get established 

 on the leaves. As a tea or decoction it is also often used by nursery- 

 men against the lice which infest plum, cherry and other nursery 

 trees. Tobacco stems, or any other cheap form of tobacco, is 

 steeped and to the liquid thus prepared is added whale oil soap at 

 the rate of about one pound for from six to eight gallons. Tobacco 

 diiiers much in its strength and before using this preparation of 

 whale oil soap and tobacco it should first be tested on the foliage to 

 see how strong it may be used without injuring the foliage. No 

 other method of determining the best strength at which it may be 

 used can be safely followed. The preparation, after being properly 

 diluted, is poured into shallow pans and the infested twigs are bent 

 over and dipped in it. The lice at first are found chiefly on the 

 tender leaves at the growing tip. The leaves soon become curled 

 so that it is impossible to hit all insects with a spray and therefore 

 dipping seems to be the best remedy in such instances. If careful 

 watch is kept for the first appearance of the insects spraying can no 

 doubt be used effectively if done promptly and thoroughly. Kero- 

 sene emulsion should then be used. It may also be used for dip- 

 ping, diluted from twelve to fifteen times. Care should be taken 

 that the emulsion is perfectly made and no free oil left floating on 

 the surface, or the foliage will be injured by the oil. 



Whale oil Soap. — This is used in solution chiefly against soft 

 bodied insects such as plant lice. It is commonly combined with a 

 decoction of tobacco as stated above, at the rate of a pound to about 

 eight gallons. When applied alone without the tobacco it is used 

 stronger, taking one pound of soap to four or five gallons of water. 



18 Bulletin 86 : 7, and Annual Kepoitof New Jersey Exp't Station, 1892 : 403. 



