Vol. IX. Xo. 217. 



THE aqricultuhal news. 



209 



STUDENTS' CORNER. 



AUGUST. 



THrRii Pi:niori, 

 Seasonal Notes. 



The disease of cotton known as 'black ^nn' is prevalent 

 to some extent in the West Indies. In its ordinary manifesta- 

 tions, it attacks a small urea of the stem, or a branch, which 

 becomes brown in colour, gradually darkens, and finally leads 

 to the bending over of the stem or branch affected. Exam- 

 ine cotton fields for evidence of the presence of this disease, 

 and where it is found, try to discover if there is any 

 connexion between the prevalence of it and that of black boll 

 and anthracnose. In ISarbados, more cspeciall}', it will be 

 well also, to make observations for the purpose of tracing anj' 

 connexion that may possibly exist between the attacks of the 

 disease and those of the red maggot. 



When the cotton plants begin to bear bolls in any 

 quantity, it may be noticed that a large number of them are 

 dropped, while they do not show any definite signs of disease. 

 On the occurrence of this, the pre.sence of the condition 

 should be considered in relation to the state of health of the 

 plants, and to the rainfall at the lime. The reason why 

 a plant drops its fruit, though this is still healthy, is 

 because the amount of nutritive material that is being 

 made is insutticient for the maturing of the number of 

 fruits already on it. This interference with nutrition 

 may arise from a disea.sed condition of the plant which 

 prevents food substances from being carried through it prop- 

 erly, or does not allow the leaves to exert their function of 

 assimilating carbon to a sufficient extent: or it may be caused 

 through the effect on the plant of a sudden fall of rain or 

 a quickly oncoming drought. In the first case, the plant 

 must be helped as much as possible by adoj)ting means for 

 getting rid of the pests. There is no artificial remedy for the 

 second condition; it is a natural stivte, and is probably bene- 

 ficial in the long run; for though the number^ of mature bolls 

 given by the tree will be fewer than if manj' of them had not 

 dropped, the tree itself has manage<l to conserve its strength, 

 and the fewer bolls that ripen will give better cotton than 

 would have been received from the many, had they not droii- 

 ,ped to some extent. 



Yarns should be examined carefully for the presence of 

 a disease, called ' blight ' in Barbados, which is probably due 

 to bacteria. Where it is found, s|iecinu'ns showing symp- 

 toms of the attack should be forwarded to the chief agricul- 

 tural officer of the colony, for transmission to the Head 

 Office and examination by the Mycologist. An interesting 

 experiment on the yield of yams may be performed by staking 

 about a hundred holes, so that the aerial stems may climb, 

 and comparing the yield from these with that from a hundred 

 neighbouring holes where stakes have not been put in. At 

 the end of the experiment, it will be of interest to find 

 reasons for the difference in the weights of tubers given in 

 the two plot.s. Compare the structure of the yam tuber with 

 that of the root of the sweet potato, and of the bulb of the 

 onion. What is the true nature of the ' eyes ' on a yam, and 

 what usually hajipens to them when it is put into damp soil. 



Sweet potatos will soon be put in, for the next crop. 

 Note whether the cuttings plwnted are obtained from plants 

 grown from roots, or from tho.se raised from cuttings. It will 

 be of interest to plant cuttings of the two kinds, in different 

 plots under the same conditions, and to weigh carefully the 

 produce obtained in the two cases. A\ hy is it that, although 

 the underground part of a sweet i)otato is not a tuber, it can 



be used for the production of new plants? Examine the 

 different kinds of sweet potatos grown in your district. 

 Ascertain the local name of each kind, and write a careful 

 description of it. Such careful descrii)tions, with local 

 names, w^ould probably be of great use if they were communi- 

 cated to the officers of the Department. 



Where shade has been provided already, by the growing 

 of bananas and tanias, the planting of cacao will now be in 

 train. While this is being done, it is of the utmost impor- 

 tance to make sure that the drainage is good, as cacao is one 

 of the first plants to show ill effects from the continual 

 presence of too much water in the soil Remember that drains 

 are almost useless, even when they are sufficient in number, 

 unless they are deep enough. They have to remove a great 

 deal of the water that is on its way through the soil, and if 

 they are wanting in depth, much of this will be able to 

 pass down to levels from which they cannot remove it. For 

 what ])urpose, in cacao cultivation, may drains be used, besides 

 that of the removal of water? 



Mature cacao trees are now flowering for the Christinas 

 crop. E.xamine the structure of the cacao flower, and make 

 observations on it for the purpose of deciding how it is pollin- 

 ated On what kind of structure, and on what parts of the 

 plant, are the flowers borne ! Discuss the importance of the 

 exercise of care in picking cacao, in relation to the production 

 of flowers for the next crop. 



In a caciio plantation, the signs that any of the trees are 

 suffering from the wind are unmistakable, and where they 

 are seen, no time should be lost in providing effective wind- 

 breaks. It is at the pre.sent season that vacant places in the 

 plantation should be filled. Care will be required now, 

 especially, to prevent the spread of wood ants, and the nests 

 will be poisoned by means of white arsenic, with precautions 

 again.st the picking up of the poison by other animals. As 

 has been indicated already, the grafting of selected varieties 

 of cacao may now be done. Keep a watch for cacao canker, 

 and in this connexion read carefully the two recent articles 

 in the Agricultural Neivs (pp. 222 and 238), which contain 

 interesting information in relation to this disease. 



Questions for Candidates. 



PRELIMINARY QUESTIONS. 



(1) State what you consider to be the best method of 

 manuring for sweet potatos, giving reasons. 



(2) To what special characteristics does farmyard manure 

 owe its great value? 



(3) What are the chief grasses used in your district for 

 fodder, and how are they respectively affected by dry weather 



IXTERiIEDI.\TE QUESTIONS. 



(1) What parts of an ordinary soil have the greatest 

 influence in retarding the loss of water? 



(2) State the .sj'mptoms of areolate mildew of cotton, and 

 describe briefly the fungus causing it. 



(3) Give as many reasons as you can for pressing down 

 the surface of the soil after planting seeds. 



DEPARTMENT NEWS. 



-Mr. \V. N. Sand.s. Agricultural Superintendent of 

 St. Vincent, left for Canada, on the 8th instant, for 

 the purpose of assisting in advancing the interests 

 of the West Indies at the forthcoming Canadian 

 Exhibitions at Toronto and St. John, especially in 

 the matter of extending trade between these colonies 

 and the Dominion. 



