Relation of Weather to Crops 87 



Crystal Wax, WhiteBermuda, Yellow and Red Bermuda, and Aus- 

 tralian Brown are the most popular varieties. Australian Brown 

 is the best keeper, but it is not a sure crop in the warmest valleys. 



Yellow Danvers is successfully grown in the cool sections. 



oranges 



While oranges are being grown to an increasing extent on the 

 ■upper slopes of the Salt River Valley, on the mesa near Yuma, and 

 in some other localities, the area in Arizona where their culture 

 may be profitably engaged in is quite limited when compared with 

 the total of cultivated land. Orange trees being semitropical ever- 

 greens are severely injured when the mercury falls to 20', and 16" 

 will often kill the trees to the ground. The intense heat of summer 

 is also very apt to injure the trunks unless the trees are headed 

 low and properly pruned. For these reasciis orange culture re- 

 quires more skill and is attended with somewhat greater expense 

 than in other orange growing localities. The incentive to grow 

 oranges in a commercial way under these conditions is the high 

 price received in the eastern markets for the Washington Navel 

 variety, which ripens its fruit somewhat in advance of the 

 California crop. 



Partly on account of the hot dry climate citrus trees are not 

 at present infested with scale insetts. The chief insect enemies of 

 the orange are several species of thrips of which Euthrips tritici 

 is b}^ far the most common. They distort the foliage and scar the 

 fruit with considerable detriment to its selling value. Washington 

 Navel is perhaps the most profitable vaiiety. Valencia, Ruby, St. 

 Michaels, Jaffa, and Mediterranean Sweet are also grown. 



PEACHES 



The different varieties of peaches differ considerably in their 

 relation to the climatic conditions of the region. vSome varieties 

 escape injury from frosts most seasons and endure well the heat of 

 summer. These varieties belong mostly to the Chinese type of 

 peaches, blooming so early during the winter that the young fruit 

 has attained sufficient size to endure quite low temperatures. As 

 a result they set full of fruit every year. Other varieties not only 

 receive considerable injury from spring frosts, but do not endure 

 well the heat of summer. Peach trees are longer lived than apple 

 or plum trees, but not so long-lived as either apricots or almonds^ 



