266 Bulletin 38. 



have to thank their numerous parasitic and predaceous enemies. 

 Observe the flies hovering over a cabbage patch ; these are the 

 syrphus-fiies which lay their eggs among the lice ; and from these 

 eggs hatch maggots which feed voraciously upon the lice, and ul- 

 timately turn into other flies like their parents. So also the little 

 red beetles, so common wherever plant-lice abound, are the lady- 

 birds which destroy more lice than we can count. Ignorant peo- 

 ple sometimes are alarmed at the numbers of red lady -birds, and 

 even think that they are the parents of the lice, but they could 

 not make a greater mistake. 



As regards the remedies for naked plant-lice, much depends 

 on the kind of louse, the plant attacked, and the time and place. 

 A good deal of work needs to be done in Arizona before we know 

 what plant-lice occur there, much less how to deal with them. 

 But in a general way, various suggestions may be offered. 



Much may be done against most kinds, especially those living 

 on fruit trees, by a spray of kerosene emulsion. The lice are soft 

 and naked, not protected like scale-insects, so they are readily 

 destroyed. Dr. J B. Smith says : "As a general insecticide, 

 nothing is better than kerosene emulsion, which, when diluted 

 ten times with water, kills all the young forms and adults of the 

 green species. It has been found by experiment that the black 

 or brown species are much more difficult to destroy, and one part 

 of emulsion in six or eight parts of water is more likely to be 

 effective. " (See note). 



The grey cabbage-louse, so well known to all raisers of vege- 

 tables, lives during the winter on old cabbage stumps. It is 

 therefore of the utmost importance to remove them from the field 

 and burn them, as well as all sorts of loose trash and weeds. 



Note— Kerosene emulsion, milk formula — kerosene, 2 gallons; sour milk, i gallon. 



Heating is unnecessary; churn three to five minutes, or until a thick, buttery consist 

 eucy results. Prepare the milk emulsion from time to time for immediate use, unless it 

 can be stored in air-tight jars; otherwise it will soon ferment and spoil. 



How to use the emulsion— For summer applications for most plant-lice and other soft-bodied 

 insects, dilute with 15 to 20 parts of water; for the red spider and other plant mites, tht 

 same, with the addition of one ounce of powdered sulphur to the gallon; for scale insects, 

 the larger plant bugs, larva and beetles, dilute with 7 to 9 parts of water. 



Foi subterranean insects, such as root lice, root maggots, "white grubs," etc., use either 

 Kerosene emulsion or resin wash, wetting the soil to a depth of 2 or 3 inches, and follow 

 with copious waterings, unless in rainy season. Year Book, U. S. Dept Agriculture. 



Spray Pumps— Full information about spray pumps, styles, cost, and where obtained will 

 be supplied on application to TRE EXpERIMENT STaT ION, Tucson. Arizona 



