Vol. XV. No. 369. 



THE AGRICULTURAL SEWS. 



203 



aflected by the disease in wet seasons. Besides the damage 

 described, a severe attack of the stainei" may cause the trees 

 to shed their bolls before they attain th'eir full development. 

 Lq one case nearly all the bolls on a tree were shed. These 

 when examined were found to be completely disorganized 

 internally. 



The case against the silk-cotton tree may be summed up 

 as follows: It is a tree which, when it fruits, provides 

 a large amount of food for the cotton stainer, and so enables 

 the insect to feed and breed e.Ktensively, and tide over 

 a season when it is so important that its numbers should be 

 reduced to a minimum for the protection of the annual 

 cotton crop, planted in May, .Tune and July; therefore, it 

 should be destroyed or prevented from fruiting. 



In some cases it is not desirable to destroy a tree, on 

 account of its age or its usefulness as providing shade. In 

 these circumstances such trees can be -pruned back as soon 

 as flowers are seen. There is no danger in taking this course 

 because the cotton stainer only feeds on the bolls. This 

 method has been successfully adopted at the Botanic Gardens, 

 and it is expected that .some years will elapse before the 

 trees flower again. It should also be mentioned that the 

 silk-cotton tree does not fruit every year, and it is only 

 a menace to the cotton indu.stry when it does so. 



This article will be continued in the ne.xt issue of the 

 Agricultwal Ntivx with regard to the .John Bull or Gamboge 

 tree (Thespesia populnea) as a native food plant of the 

 cotton stainer This tree is an even greater menace to the 

 cotton industry than the silk-cotton tree. 



AGRICULTURE IN COLOMBIA. 



Mr. M. T. Dawe, who was recently appointed Agricul- 

 tural Adviser to the Colombian (government, has recorded 

 some impressions of the present condition and possibilities of 

 agriculture in Colombia received during a journey from 

 Santa Marta to Bogota. 



In Santa Marta there are two agricultural zones, a lower 

 and an upper, characterized respectively by the cultivation of 

 the banana and coffee. The export of bananas for the year 

 1915 had been estimated at 8,000,000 bunches, but it is now 

 calculated that 2,500,000 bunches less will be exported 

 owing to the extensive damage caused by a tornado. 

 Although there is already a bi-weekly service of steamers 

 engaged in carrying bananas to the United States and 

 Europe, there seems to be room for considerable expansion 

 of the trade. The rainfall in the lower zone is so irregular 

 and uncertain that, apart from such xerophytes as Agave, 

 cultivation oil a commercial scale is practically impossible 

 without irrigation. This zone shoidd be very suitable for 

 the cultivation of Agave, in which, owing to its favourable 

 geographical situation and facilities for transport, Santa 

 Marta might become a formidable competitor of Tropical 

 East Africa. Although the physical conditions are suitable 

 for the cultivation of cotton, it is improbable that this could 

 be profitably grown on a commercial scale, owing to the high 

 rate of wages. 



Para and Guinea grass are used for pastures in the Santa 

 Marta region. Mr. Dawe recommends the introduction of 

 other pasture and fodder plants, and especially of the Velvet 

 bean. 



In the upper agricultural zone of Santa Marta cotiee is 

 the only plant cultivated on a large scale, the largest planta- 

 tion being the 'Cincinnati', which has about 350,000 trees. 

 Coffee seems to do best at an altitude of about 4,500 feet, in 

 the Sierra Nevada. The trees are sown at intervals of about 

 8 feet, and are neither topped nor pruned. The shade tree 

 employed is the guamo ( Inga dulcis). The average annual 

 yield of dry coffee per tree is said to be I tb., and in exception- 

 ally favourable years as much as 1 ift). The trees seem to 

 suffer from over-shading, and better results might be obtained 

 by the use of species of Albizzia or Erythrina as shade 

 trees, coupled with judicious topping and pruning. A disease 

 affecting both the leaves and fruits of the coffee, on which it 

 appears in the form of round blotches, is probably caused by 

 the fungus Omplialiafai'idjt, Cooke. It is most abundant 

 in deep ravines and shady places. 



From Santa Marta, Mr. Dawe travelled by rail to 

 Cienaga, and thence by steam-launch to I'>aranquilla, passing 

 extensive stretches of mangrove swamps. Small (|uautities 

 of mangrove bark are exported to New York via Puerto 

 Rico, but there is no doubc that many thousand tons 

 could be exported annually, it the Majjdalena delta were 

 suitably exploited. Tlie mangrove bu'k destined for export, 

 seen in Barranquilla, was divided intj large pieces, wherevs 

 that exported from ^ladagascar and East, Africa is cut into 

 .small pieces, 5 inches long and 2 inches broad. 



The most noticeable thing in the journey up the River 

 Magdalena, from Barranquilla to Giradot, was the great 

 extent of fertile alluvial land, capable of producing enormous 

 crops of sugar, cacao, rubber and other tropical products; 

 but the country is very sparsely inhabited, and the inhabi- 

 tants obtain their living by cutting wood for the passing 

 steamers, and grow no more food than is re(piired for their 

 own needs. 



The first step in the development of this region should 

 be the improvement of the navigable channel of the Magda- 

 lena. The practice of cutting the trees on the river banks 

 should be prohibited, as this leads to the washing away of 

 the banks. 



The condition of agriculture in the Lower Magdalena 

 region might be greatly improved by the establishment of a 

 model plantation conducted on commercial lines, where sugar, 

 cacao, rubber, cotton, maize, rice, kidney beans, etc., could 

 be grown, and the best methods of cultivation demonstrated. 



Immense areas of the Lower Magdalena basin are 

 covered with forests which might, under suitable adminis- 

 tration become one of the principal .sources of revenue in 

 Colombia, judging from the large selection of useful woods 

 .seen by Mr. Dawe at Barranquilla. A duty should be 

 imposed on each tree of certain kinds that is felled, and the 

 work of reafforestation should be taken in hand in areas where 

 the forests have been destroyed. This is especially necessary 

 in the Upper Magdalena region, where there is a scarcity oi 

 wood for the steamers in certain places. 



The estate of Santa Sofia, at Giradot, was examined 

 with a view to its suitability as the site of an agricultural 

 experiment station and college. The means of communication 

 are very good, as Giradot is the junction of the railways to 

 Bogota and the Pacific Coast, and the upper limit of steam 

 navigation on the Magdalena. The soil of the district is of 

 medium quality and suitable for the cultivation of Agave, 

 but other crops would probably reijuire irrigation. 



Evidence of the ravages of locusts was .seen throughout 

 the journey, and Mr. Dawe recommends the establi.shment of 

 a Locust Bureau to control the pest. (Kew Ikdletin of 

 Miscellaneous Information, No. 10, of 1915.) 



