COST OF PRODUCING APPLES IN YAKIMA VALLEY. a 
The codling moth is perhaps the worst pest of the valley, but with 
thorough spraying at the correct periods it is believed that it may be 
controlled. The other insect pests of economic importance now 
known to be in the valley are San Jose scale, oyster-shell scale, 
Lecanium scale, woolly aphis, green aphis, and rosy-apple aphis. 
Apple and pear scab are now found to a limited extent, but thus 
far have caused but little damage. 
CLIMATE. 
The climate of Yakima Valley is decidedly arid, and without 
irrigation the growing of agricultural crops would be impossible. 
The temperature during the summer often reaches 100° F., but be- 
cause of the relatively low humidity it is not oppressive. The winters 
are generally mild with but light snowfall. 
There was an annual average of 187.4 growing days at Yakima 
in the five years 1910-1914, inclusive. The Ahtanum Valley itself 
is well protected from severe winds; but in the lower valley, where 
the country is more open, winds often cause crop damage. 
The mean annual precipitation for the five years 1910-1914, 
inclusive, at an altitude of 1,070 feet, North Yakima was 6.64 inches; 
in the Moxee Valley at an altitude of 1,000 feet it was 7.47 inches. 
For the 22 years 1893-1914, inclusive, the mean annual precipitation 
of the Moxee Valley was 8.36 inches. The greatest precipitation 
takes place in the months of November, December, and January, and 
the least occurs in the months of April, July, and August. 
For the most part the climate of Yakima Valley may be said to be 
very pleasing and healthful. 
TOPOGRAPHY. 
Yakima County receives its water for irrigation purposes from the 
Yakima River and its tributaries. This river has its source on the 
eastern slope of the Cascade Mountains, taking an easterly and 
southeasterly course, entering the northern part of Yakima County 
and flowing into the Selah Valley, a plain about 4 miles in length. 
At the end of this valley it passes through a narrow gap into 
the upper Yakima Valley. From here it pursues its southerly 
course east of the city of North Yakima and about 6 miles south 
passes through what is known as Union Gap and enters its lower 
valley, in which are located Parker, Zillah, and Sunnyside. The 
upper valley is bounded on the north by Selah Ridge and Cowiche 
Ridge, and on the south by Yakima Ridge and Ahtanum Creek. 
The valley between the Yakima and Selah Ridges east of Yakima 
River is known as the Moxee Valley and that between Yakima and 
Cowiche Ridges west of Yakima River is known as the Ahtanum 
Valley. The total length of this valley is from 75 to 80 miles and the 
width is not greater than from 5 to 6 miles. The slopes of the 
