322 



THE AGRICULTUKAL NEWS. 



October 20, 1906. 



destruction of the vegetative portion of the parasite or 

 its reproductive spores, whilst in active growth on the 

 host-plant, can be accomplished by the use of various 

 fungicides. These should be used rather as preventives, 

 and are more successful in combating diseases of 

 leaves and fruit than where deep-seated mycelia have 

 to be dealt with. 



(2) The destruction of plant tissues containing 

 resting forms of the fungus must not be overlooked. 

 The ideal method, of course, is to burn all such 

 plant remains ; but often this is impossible. There are 

 many plants or portions of plants that contain too much 

 water to burn satisfactorily, and these should be buried 

 with lime. The addition of lime hastens decay and 

 prevents local souring of the soil by the addition of 

 large quantities of decaying matter. The burial of all 

 diseased cacao pods, as well as the husks or shells of 

 healthy pods, left after the beans have been extracted, 

 has resulted in the prevention of the spread of the 

 'pod diseases ' of cacao, and also in the enrichment of 

 the soil. 



(3) In many cases it is impossible to avoid con- 

 ditions which are favourable to infection. In damp, 

 warm weather, spores of fungi are less readily distribu- 

 ted by the wind, but they stand a much better chance 

 •of germination. Unfavourable conditions of the soil, 

 also, are often the cause of the rapid spread of root 

 diseases, and careful attention to drainage, cultivation, 

 etc., would successfully check their spread, and at the 

 ■same time give a more vigorous crop, capable of 

 resisting further attacks of disease. 



The isolation of affected areas by means of a trench, 

 ■so as to prevent the spread of the mycelium through the 

 ■soil to still healthy plants, should confine it to certain 

 areas, which should then be cleared and treated with 

 large quantities of lime in order to kill out some, if 

 not all, of the 'roots' of the fungus. 



The fungus of a root disease may often be starved 

 ■out by the rotation of crops. In the case of temporary 

 crops, like the sugar-cane and cotton, this can easily be 

 ■carried out ; but in the case of such permanent crops as 

 cacao it' is impossible. However, when a cacao or 

 similar tree has died from a root disease, the diseased 

 roots should be destroyed, and the ground allowed to 

 remain some time before another tree is planted. 



A large number of fungi can bring about infection 

 of their host-plants only through breaks or wounds. As 

 long as the protective layers are sound, the plant 

 remains free from the attacks of such wotmd parasites, 

 .and, therefore, pruning and fruit-picking should be 



carefull}' done. The- canker of cacao is caused by 

 a wound parasite, and if careful attention were given to- 

 pruning, etc, as well as to the tarring of all wounds,, 

 conditions likely to bring about infection would be 

 avoided. The treatment of cane cuttings, frequently 

 recommended by the Imperial Department of Agri- 

 culture, should be continued, as investigations show 

 that this is a means of preventing, to a certain extent, 

 infection by the mycelium of the root fungus. 



(4) The raising of disease-resisting varieties is 

 becoming recognized as a matter of considerable 

 importance. Some varieties are more or less free 

 from disease, while others, cultivated under the same 

 conditions, are especially susceptible to it. The varieties 

 that are least susceptible to disease should be selected 

 for future cultivation, if they possess the other desirable 

 qualities. The wilt disease of cotton and cowpea has 

 successfull}' been overcome by selecting immune 

 varieties, while many .«eedling sugar-canes are capable 

 of withstanding certain fungoid diseases much better 

 than the older varieties. 



(.5) The importation of plants from infected areas 

 has often resulted in the introduction of new fungoid 

 diseases, and many countries have formulated laws to 

 prevent such occurrence, as has already been done in 

 the case of insect pests in many West India Islands. 

 It IS hoped that the different Governments will also 

 prohibit the importation of seeds or plants from 

 localities affected with fungus diseases, or allow their 

 importation only after disinfection at the port of entry. 



SUGAR INDUSTRY IN FORMOSA. 



The Consular Report on the trade of Tainan, 

 South Formosa, for 1905, has the following reference to 

 the progress of the sugar industry : — - 



It is expected that, as the native Chinese become more 

 experienced, they will adopt more modern machinery, and 

 that eventually there will be a regular central factory system. 

 Owing to the ditticulties caused by inexperience in working 

 new machinery, the 190.5-6 crop has not been worked off as 

 quickly as usual, and there is consequently a le.sser area of 

 cane planted for the coming season, 1906-7, than in 190.3. 

 This is partly due to the low prices received during the 

 190.5-6 season. But although the area planted is les.s, it is 

 expected that the hew crop for 1906-7 will not be much 

 smaller than that for the previous season, on account of the 

 large increase in 'rose bi\mboo' sugar-cane planted. This cane 

 yields about three times the quantitj', area for area, produced 

 by the old-style bamboo canes, which are raiiidly being 

 abandoned, and it is anticipated that, within the next few 

 years, there will be no more old-style bamboo canes left, 

 except in places which are not suitable for the ' rose bamboo.' 

 It is calculated that the out]>ut per acre from the old-style 

 bamboo canes is from 10 to 15 tons per acre, and from the 

 'rose bamboo' about 30 tons per acre. 



