302 CALIFORNIA VEGETABLES 



back into itself with nozzle and force pump. The last is the com- 

 monest way. When the agitation is adequate practically the whole 

 of the mess changes form and becomes like clabbered milk, and this 

 is added to ten or more times its bulk of water, according to the 

 strength you desire to use. One to 20 is strong enough for plant 

 lice. The essential is not in strength, but in getting the dope on the 

 bug with a garden syringe or spray-pump, and it will kill all in- 

 sects which are covered with a film of it. A fine rose sprinkler can 

 be used, but it is wasteful and the application does not penetrate, as 

 well as from a spray-nozzle. 



Next in importance to oil emulsions in the warfare against 

 sucking insects are the tobacco preparations and they are so efficient 

 against some small pests like aphis, thrips, white fly, etc., that they 

 are often added to the water used in diluting the emulsions. To- 

 bacco preparations are both home-made and commercial. One 

 pound of tobacco leaves or stems steeped in four gallons of hot 

 water produces a good insecticide. The commercial extract con- 

 taining 40% of nictotine is used at the rate of one pint to two 

 hundred gallons of water or of diluted emulsion. Nicotine extracts 

 are sold under various names as insecticides by druggists and seeds- 

 men and are usually worth their higher cost because of convenience 

 in securing small quantities ready for use. 



The emulsions and tobacco washes will, of course, kill many 

 insects for which poison has been prescribed and are available 

 whenever the use of poison is thought to be undesirable. They 

 have their limitations, however: the stuff must be thrown on the 

 insect while poison will wait for the insect to come to it. 



WAYS WITH PARTICULAR PESTS. 



The vegetable grower will be armed against insects if he is 

 ready with the few insecticides we have described to be placed 

 upon the insect's food or upon the body of the insect, as the nature 

 of his work on the plant indicates, but he must not get the idea that 

 the warfare is easy. The appalling rapidity of insect reproduction 

 and the no less appalling number of the kinds of them ; the sudden- 

 ness of their appearance and the diversity of the ways in which 

 they make their attacks all these should warn the grower to watch 

 his plants closely and to strike fast and hard as soon as he sees the 

 first of the hosts of invaders which he must learn to expect. In 

 the battle with pests an early beginning is more than half the 

 winning. * 



Although it is obviously impossible to include in a handbook of 

 general practice with vegetables detailed account of all pests likely 

 to be encountered, it may be useful to compile a sketch of frequent 



