408 THE MONTHLY BULLETIN. 



The navel orange groves of trees of our west and of several foreign 

 countries are directly descended from the Tibbets trees. The great 

 commercial success of the navel orange industry in California is the 

 foundation upon which the successful citrus industry of this state as a 

 whole has been built. 



The oldest navel orange trees found in Brazil were more than forty 

 years of age. They are now producing the largest and best crops of any 

 trees found in that district. 



The method of tree renewal for treating diseased trees in Bahia is a 

 success. The replacing of diseased trees by growing a new top is univer- 

 sally practiced in that region. 



The use of manure in maintaining the citrus trees in productive condi- 

 tion and improving the quality of the fruit is an established and 

 successful practice. The liberal use of manure is considered to be 

 absolutely essential to profitable citrus production. The average annual 

 production is about one hundred navel oranges per tree. 



Scale and other insect enemies of the citrus are evidently controlled 

 by natural parasites. 



The Bahian navel fruits are very different in appearance, quality and 

 other commercial characteristics from California fruit. For this reason 

 we may safely conclude that no one can foretell exactly the behavior of 

 plants under new environmental conditions. Consequently all food 

 plants introduced should have a wide and careful trial, and in our 

 opinion all foreign food plants should be tried without too fixed ideas 

 as to their probable behavior in anj' particular region. 



The shipment of bud wood or trees from Brazil is attended with both 

 difficulty and danger. Great care must be used in packing and condi- 

 tion of storage and shipment in order to preserve the buds in living 

 condition. The bud wood should be inspected with the greatest possible 

 care in Brazil and in the United States in order to prevent the introduc- 

 tion of insect enemies, fungous diseases or other parasitic pests. 



The discovery of the Bahia navel orange by a traveler in Brazil is a 

 good illustration of the importance of careful observation of food plants 

 in foreign countries by all travelers. All information about new food 

 plants found in this way is likely to prove of value. Through the office 

 of Seed and Plant Introduction of the United States Department of 

 Agriculture, such information can be followed up, and if desirable, 

 supplies of bud wood or seed be obtained for trial in this country. 



We found a total of about 76,000 navel orange trees near Bahia. The 

 orchards are located on hilltops or hillsides. The orange growers are 

 prosperous and an effort is being made by the local government to 

 extend the culture of this variety. 



A permanent cover crop of Para grass in connection with the liberal 

 use of cow manure was the most successful method of culture observed, 

 under the conditions of an average annual rainfall of about fifty inches. 



Citrus bud sports are common in the orchards observed. The origin 

 of the navel orange from this cause is proof of the importance of this 

 condition in the improvement of citrus fruits. 



