Orchard Pests and their Control 387 



Black-leaf Sheep Dip. A proprietary decoction of tobacco 

 which has recently come into prominence as a contact poison in 

 combating sucking insects. It is used on dormant trees as strong 

 as one gallon to 25 gallons of water. For use during the grow- 

 ing season one gallon of Black Leaf to 70 gallons of water is com- 

 monly used. 



This preparation is being generally adopted as the best poison 

 for combating the different forms of aphis. 



Whale-oil or Tree Soap. For ordinary plant lice one pound 

 of the soap to eight or ten gallons of water is sufficient if the ap- 

 plication is thorough. Double this strength will not injure most 

 plants and is often required to destroy more resistant insects. 

 For scale lice, like the San Jose scale, for example, it is used as 

 strong as one pound, or even two pounds to a gallon of water. 

 These strongest applications can only be used in the winter or 

 early spring when the trees are dormant. The soap is more 

 effectual if applied when quite hot. The soap solutions kill by 

 contact only. 



Lime-sulfur Wash. This wash, when properly made, is one 

 of the most effectual applications for the destruction of scale in- 

 sects and eggs of the brown mite by contact, particularly in dry 

 climates. It should be used only in the winter or spring, while 

 the trees are dormant. The ingredients may be in the following 

 proportions : 



Lump lime (good) 20 pounds 



Sulfur 15 pounds 



Water 50 gallons 



Slake the lime, preferably with hot water, in an iron kettle or 

 a barrel, and while slaking, slowly add the sulfur and stir it in. 

 Then boil over a good fire or by means of a jet of steam in about 

 one-half the required amount of water (25 gallons) for 45 minutes 

 or until a dark red color is obtained. 



The need of a fungicide to replace bordeaux mixture has led 

 to experiments with various sulfur mixtures. A recent bulletin 

 of the United States Department of Agriculture reports favor- 



