PESTS AND DISEASES OF PLANTS 231 



permanganate of potash. Eliminate infected fruit and disinfect boxes 

 and picking sacks. 



Dieback (Bacterial). Improve physical conditions of trees by 

 deeper and more thorough tilling of soil. If excessive applications of 

 nitrogenous fertilizers have been made, discontinue until tree has 

 resumed normal conditions. 



Mottle Leaf (Physical). Improve physical condition of tree by 

 deep culture. Make applications of lime and manure to soil. Examine 

 soil as to hardpan, and if it exists, break up if possible. 



Smut. A fungous growth caused by honey dew exuded by scale 

 insects, plant lice and white fly. Remove pest and smut will disappear. 



Wither Tip. Apply Bordeaux as soon as it appears and repeat as 

 often as necessary. 



Olive. 



Black Scale. Best treatment, fumigation, October-January. If 

 sprayed use resin wash or distillate emulsion. Annual spraying not 

 effective. When young insects appear in large numbers on leaves and 

 stems apply spray. Two or three sprayings may be necessary in some 

 years; in others none. 



Twig Borer. Cut off twigs and prune. 



Dry Rot of Fruit. Keep trees free from other pests, well pruned 

 out so as to admit light and air. 



Olive Knot. A bacterial disease in the form of a woody tumor. 

 Attacks most vigorous trees. Distributed principally by pruning tools. 

 After pruning dip tools in corrosive sublimate. Cut off all tumors, re- 

 moving the entire twig when possible, and burn. 



Peacock Leaf Spot. Fungus on leaves and fruit. Spray with 

 Bordeaux. 



Peach, Nectarine, and Apricot. 



Aphis, Black Peach. For those above ground use kerosene emul- 

 sion or tobacco wash. Destroy the underground forms by pouring 

 carbon bi-sulphide into holes in the ground (made by a crowbar) six 

 inches to six feet away from the tree and about two feet apart. Pour 

 21 around base of tree often. 



Apricot Scale. Apply distillate emulsion or tobacco washes just 

 as soon as the leaves fall. All applications should be made before the 

 first of December. 



Black Scale. Same as Apricot Scale. 



Borer, Peach Tree. Dig out and kill, or destroy by inserting a 

 flexible wire into their burrows. A strip of asphaltum six inches wide 

 on butt of tree is also used. 



Bud Moth. Use lime-sulphur during winter months when tree is 

 dormant. Use lead arsenate just before leaf-buds open and just after 

 blossoms fall. Repeat every ten days if necessary. 



San Jose Scale. Spray with lime-sulphur when trees are dormant. 



