366 Fruit-growing in Arid Regions 



time when the winged lice begin to fly about to spread the 

 species. 



Wherever this louse can be reached by sprays, it may be de- 

 stroyed like other plant-lice, but the spray must be applied with 

 sufficient force to remove or penetrate the woolly covering. 

 There are several spray materials that we have found to be en- 

 tirely successful when thoroughly applied to this insect. 



Black-leaf is, all things considered, by far the best spray for 

 plant-lice that has yet been introduced. It gives no better re- 

 sults than kerosene emulsion when properly made, but the diffi- 

 culty our growers experience in making a good emulsion with the 

 universal alkaline water makes its use almost prohibitive. At 

 any rate, very few growers attempt to make it. Black Leaf is a 

 tobacco decoction which was originally manufactured as a sheep 

 dip. It has been given a thorough test by many orchardists, 

 and has given universal satisfaction. It is used in the propor- 

 tion of one gallon to 65 or 70 gallons of water. 



So far, the remedies mentioned have been for summer treat- 

 ments, when the bodies of the lice are more or less covered with 

 the waxy secretion. We think the best time to get results in the 

 treatment of this louse is late in the winter, or early in spring 

 before the buds open. This is not because the lice find protec- 

 tion from the opening buds, but because by the time the buds 

 have opened, the lice have their bodies more or less covered by 

 waxy secretions that protect them to some extent from the effects 

 of the insecticides. 



Many orchardists have found that when they used the lime- 

 sulfur mixture for the destruction of the eggs of the green apple 

 aphis, they largely freed the trees from woolly aphis at the same 

 time. 



The following formulae have been found to be reliable: 



Lime 15 pounds, sulfur 15 pounds, water 30 gallons; 

 Lime 15 pounds, sulfur 15 pounds, water 45 gallons; 

 Rex lime-sulfur 1 gallon, water 7 gallons, lump lime 2 pounds. 



We have no doubt that the kerosene emulsion, the tobacco 

 sprays, and the whale-oil soaps could also be used successfully as 



