66 



THE OKANGE; 



referring my readers to Mr. Cooke's 

 work.* 



The Black Scale.— This is the most 

 common, and is considered the least dan- 

 gerous of the scale family. It may exist 

 in a tree a long time without destroying it, 

 but we may be sure the effect is constant- 

 ly deleterious. The scale appears in all 

 tints from a whity yellow of the newly- 

 hatched to a brown of middle age and 

 black in maturity, and in form is a little 

 blister adhering to leaf, stem or stock. It 

 does not attach itself to the fruit. Trees 

 thus infested should be thoroughly 

 pruned and washed with a solution of 

 whale-oil soap as directed in the appendix. 



Fungus, or Smut.— This is an attend- 

 ant of the black scale. Scientific investi- 

 gation has shown that the scale excretes a 

 gummy substance called honey-dew, 

 which, in falling, attaches to the upper 

 surfaces of leaves, twigs and fruit. This 

 gum holds the dust that chances to fall 

 upon the surfaces covered by it, and the 

 mass generates a fungus growth termed 

 back smut. This smut, although seeming 

 to do no damage to the tree other than to 

 render it unsightly, must retard its growth 

 by obstructing the stomata or air-breath- 

 ing surfaces of leaves and branches. It 

 also renders the fruit unsalable, or nearly 

 so. Neither scale nor smut should be tol- 

 erated in an orchard. The whale-oil soap 

 solution extirpates both. 



The Red Scale.— This is similar to the 



black scale, except that it is somewhat 

 smaller and of a reddish color. It adheres 

 only to the under side of leaves and to the 

 fruit, and avoids the limbs and trunk. 

 The red scale is more dangerous than the 

 black and, if unmolested, will utterly de- 

 stroy an orchard in a few years. For 

 treatment see Appendix. 



The White* or Cottony Cushion 

 Scale.— This approaches more nearly to a 

 distinct animal than either of the other 

 scales and is the most dangerous of the 

 three. For full description and manner 

 of treatment see Appendix. 



Gum Disease. — Lemon trees especially 

 and orange trees occasionally, are subject 

 to gum disease, an affection of the bark 

 close to the ground. This is caused by in- 

 judiciuos irrigation. The bark splits and 

 a gum exudes. If unchecked, the disease 

 encircles the tree and kills it. The best 

 treatment upon discovering the first symp- 

 toms of gum disease is to cut away the 

 affected part and daub the wound with 

 paint, wax or tar. In irrigating thereafter 

 do not allow the water to touch the body 

 of the tree and be sure that the soil is well 

 stirred after each irrigation. 



"Die Back" and many of the other mal- 

 adies to which the orange trees of Florida 

 and some other lands are subject are 

 wholly unknown in this country. 



*NoTE.— Injurious Insects of the Orchard, Vine- 

 yard, etc., by Matthew Cooke, late Chief Executive 

 Horticultural Officer of California. Sacramento: 

 H. S. Crocker & Co. 



CHAPTER XIX. 



WASHING TREES. 



The YouNa Orchard. — When the 

 young trees are planted in orchard it is a 

 good plan to give them a thorough wash- 

 ing. Whatever of extraneous growth, 

 either scale or smut, may be upon them 

 is thus cleared off, and the trees are given 

 a clean start in life, which is as valuable 

 to them as to a man. 



Preventive as Well as Cure.— If 

 the plan is followed of giving the trees a 

 washing once or twice a year thereafter it 

 will greatly promote their vigor and in- 

 sure them against attack by the scale in^ 

 sect. Witii these pests of the orange tre© 

 the ounce «f prevention is a hundred 

 times the easiest and best. 



Washing Sovereign and Imperative. 

 —For older trees already infested with 

 scale, washing is the only reliable reme- 

 dy. When once cleaned, they too should 

 receive periodical sjJrayings and scrub- 

 bings. It might as well be accepted by 

 the orange growers of California as an un- 

 avoidable conclusion that orange trees, 

 to be healthy, productive and long lived, 

 must he washed. 



The Solution in common use for this 

 purpose is made of whale-oil or some oth- 

 er cheap and strong soap. For my use I 

 have found the addition of a little con- 

 centrated lye most efficacious. The 

 strength of the solution needs to be varied 



