ORANGE DISEASES 



1491 



Trunk Rot 



ScM^ophyllum commune 

 The trunk or large limbs decay at 

 points where they have been cut ofe or 

 injured, with the production of small, 

 white, bracket toadstools upon the sur- 

 face. Not parasitic on sound trees. This 

 also affects apples, walnuts and other 

 trees. 



Cover all large cuts or wounds thor- 

 oughly with grafting wax. 



Wither Tip— Aiithraciiose— Tear Stain 



The wither-tip fungus occurs abund- 

 antly upon dead or injured twigs, leaves 

 or trees, but is of doubtful occurrence 

 as a true parasite. This fungus occa- 

 sionally causes a decay of the fruit of 

 the orange quite different from anything 

 seen in the lemon. The wither-tip rot of 

 the orange consists in a large, rather 

 dry brown spot, starting sometimes on 

 fruit while on the tree during wet 

 weather, and gradually spreading. These 

 spots usually develop at places where 

 oranges touch each other. The same 

 spotting and decay are quite frequently 

 found to a considerable extent in oranges 

 held in cold storage, particularly if the 

 temperature is a little too low. Under 

 such conditions this fungus may develop 

 abundantly and cause a considerable 

 amount of decay. 



R. E. Smith, 



California Experiment Station Bulletin 2tS 



OBAIVGE PESTS 



Apiiids See General Article on ApMds, 



Barnacle Scale 



Ceroplastes cirripediformis Comst. 



General Appearance 



This wax scale greatly resembles the 

 Florida wax scale in shape. The body 

 is dark red or brown, and the white 

 waxy covering is mottled with shades of 

 gray. There is a spine-like projection at 

 the posterior end of the body, which is 

 hid by the wax. The length is one-fifth 

 of an inch; width one-sixth of an inch; 

 height the same as the width. This 

 species is larger and particularly higher 

 than the Florida wax scale. 



Distribution 



Principally in greenhouses. 



Food Plants 



Citrus trees, quince, myrtle, persim- 

 mon. 



Control 

 Same as for Florida wax scale, 



E. O. EssiG 



Black Citrus Louse 



Toxoptera aurantiae Koch 



General Appearance 



A small dull-black louse, scarcely over 

 1.5 mm. in length. The apterous forms 

 often appear brown, while the young are 

 a decided reddish-brown to black. Some 

 of the adults are shiny black and have 

 been mistaken for the black peach aphis 

 (Aphis persicae-niger) . It is easy to dis- 

 tinguish the winged individuals of this 

 species by the very dark and prominent 

 stigma and the single branching of the 

 third discoidal vein. 



Life History 



This species may be found in the cit- 

 rus groves throughout the entire year, 

 all stages being present. The greatest 

 numbers occur during the spring months, 

 when all the new growth may be de- 

 stroyed on the young trees by them. 

 Older trees are also attacked. The pres- 

 ence of the insects on the larger and 

 older leaves is easily told by their curled 

 appearance, a condition produced by the 

 lice. 



Distribution 



Throughout the entire citrus-growing 

 section of California. Especially abundant 

 in the southern coast counties. 



Food Plants 



All species of citrus trees, camellia, 

 Otea straussia and coffee. 



Natural Enemies 



This insect would be a far greater pest 

 were it not for its many natural enemies, 

 two internal parasites, the California lady- 

 bird beetle and the larvae of three syrphid 



E. O. EssiG 



Blacic Scale. See Apricot Pests. 



