THE MONTHLY BULLETIN. 



CALIFORNIA STATE COMMISSION OF HORTICULTURE 



Vol. VI. October, 1917. No. 10 



CITRUS CI LTURE IN JAPAN, CHINA AND FORMOSA. 



By Curtis P. Clausex. 



During the writer's recent trip to the Orient in search of beneficial insects 

 opportunity was presented from time to time to investigate and observe various 

 matters relating to citrus culture in Japan, China and Formosa. Naturally, 

 the methods employed were markedly different from those employed in Cali- 

 fornia, due to various economic factors which will be discussed later. Inasmuch 

 as citrus trees have been grown in the Orient for commercial purposes for 

 many centuries, the practices of the growers have become in a large measure 

 standardized, and it is only in Japan that the results of detailed scientific 

 research have come to be generally utilized. In this article the various methods 

 employed in the different countries will be discussed in due order. 



JAPAN. 



In Japan, according to Prof. T. Tanakawa of the Okitsu Agricultural Experi- 

 ment Station, citrus fruits have been grown for about three hundred years and 

 at the present time they are one of the most important fruit products of that 

 country. The producing area extends roughly over a range of about nine 

 hundred miles from Tokyo southwards to Nagasaki. The most extensive plant- 

 ings are found in Schidzuoka and Wakayama prefectures and the finest quality 

 Of fruit is grown in these sections. The official 1915 census gives a total citrus 



i ea of approximately seventy-five thousand acres of bearing trees. The annual 

 increase in acreage is very slight as the new plantings are usually about equal 

 to the area from which citrus trees have been removed. 



The conditions under which citrus trees are grown in Japan are quite different 

 from those existing in California. The level, fertile lands are used almost 

 exclusively for rice and barley, being considered too valuable to devote to 

 citrus trees. It is for this reason that nearly all citrus is grown upon the hill- 

 sides, often being upon steep terraces. In many cases it is necessary to build 

 a stone retaining wall ten or fifteen feet high in order to enclose sufficient soil 

 for a small row of trees. These terraces are irregular in form and are built 

 to conform as closely as possible to the contour of the hillside. This method 

 of planting renders the various operations of cultivating, harvesting, pest 

 control, etc., much more difficult. This disadvantage is in a large part offset 

 by the cheapness of labor, and all work is done by hand. 



Climate. 



The climate of the citrus belt is, on an average, somewhat colder than that 

 of southern California. Even Nagasaki, at the southern ■■ml of Kyushiu, 

 experiences frequent falls of snow during the months from January to March. 

 Since the fruit is harvested during the fall and early winter, injury is very 

 seldom done, though occasionally an extensive leaf drop occurs and the twigs 

 and smaller branches may be injured. This was the case during the past 

 season, which was the coldest experienced in many years. Under normal 

 conditions orange trees in Japan are able to withstand a lower temperature 

 during the winter than in California, this being due largely to the high 

 humidity and the relatively low temperature which usually prevails during the 



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