Fumigation and Of the insect pests of the orange, the most to be 



Spraying for feared are those which attack the fruit either 



Scale Pests. its surface or pulp. A common precaution 



against any possible insect disease in nursery 



stock is its thorough disinfection with carbon bisulphide, which no 

 insect life can withstand. 



The red scale and the purple scale, both brought into California 

 from Florida, and the black scale and the brown scale, have been 

 successfully treated by fumigation with hydrocyanic gas. The treat- 

 ment is elaborate and requires special apparatus, which is described in 

 Bulletins 122 and 152 and Circular 11, all to be had free upon appli- 

 cation to the Agricultural Experiment Station at Berkeley. 



These pests are also treated by spraying with a solution of dis- 

 tillate. 



Gum There are various forms of so-called gum diseases. One 



Disease. attacks both old and young trees at the crown and the 

 root, while another appears on the large limbs in the 

 form of a scab, and another on the trunks and main branches. The 

 most deadly of these is the root form, which is apt to break out in 

 almost any locality. This is an exudation of the sap which breaks 

 through the bark of the trunk close to the ground, and congeals in 

 the form of a gum. 



How One successful remedy for this disease is to peel off 



Treated. the bark where the gum oozes and cover the diseased 

 part with a solution of two parts of resin and one part 

 of beeswax, thinned with linseed oil. Another remedy is to crease 

 the bark from the limb to the root with a knife, then paint the entire 

 trunk of the tree with neat's foot oil. 



The new -grower may not have any of the unpleasant experiences 

 indicated above, but "forewarned is forearmed." 



FROST. 



Shutting out California has not been so subject to frost as some 

 King less favored portions of the country, but she has not 



Frost. enjoyed immunity. Repeated severe frosts in a local- 



ity demonstrate it to be unfitted to the citrus industry ; 



but some of the best orange-growing sections occasionally get a nip. 



However, human ingenuity has met the frost king and held him at 



bay. In sections liable to slight frosts, preventive measures are taken, 



such as -the planting of windbreaks, which keep out frost as well as 



wind; and the natural protection afforded the fruit by promoting 



heavy leafing. 



In cases of emergency frost is fought and conquered by the use 



of covers, dry heat, and smudges. The first named method is only 



practicable in small orchards. For details of frost fighting see "The 



Citrus in California," pages 155 to 161. 



Seldom, even in the worst seasons, will frost extend over more 



than one or two nights; and a late frost, when the orange is near 



maturity, harms it but slightly. 



The new grower is reminded that in looking out against frost he 



can seek advice from the Horticultural Commissioners of his county. 



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