Vol. V. No. 111. 



THE AGR [CULTURAL NEWS. 



227 



' A few years ago a sugar-cane pest [PerHnsiella 

 saccharicida, Kirk.) made its appearance in the sugar-cane 

 fields of Hawaii, introduced, it is supposed, from Australia. 

 It has been stated that this pest caused a monetary loss of 

 upwards of §3,000,000 to the sugar interests of Hawaii during 

 the past year. It was so destructive to the industry that 

 the Hawaiian Sugar Planters' Association a year ago joined 

 the Territorial Board of Agriculture and Forestry and 

 engaged Professor R. C. L. Perkins, then Acting Su[)erin- 

 tendent of Entomology for Hawaii, to accompany Professor 

 Koebele on a mission to Australia to search for the natural 

 enemies of the "cane leaf hopper." It did not take their 

 trained eyes long to discover the insects that were holding 

 that pest in check. A few of each were successfully 

 introduced and established here, and now they have been 

 propagated and planted on the various islands and are well 

 established wherever placed. One of the most important 

 is a very minute fly that destroys the eggs of the " leaf 

 hopper " by inserting its ovipositor in the leaf hopper egg and 

 depositing therein an egg, which soon hatches into a small, 

 blind, footless grub, afterwards changing to a pupa and fly, 

 and in the latter stage it cuts its way out and is soon ready 

 to continue the good work.' 



Peru as a Sugar-growing Country. 



The Louisiana Planter, of April 21, 1906, has 

 the following : — 



All the conditions of Peru (writes a correspondent of 

 the Sugar-cane) are conducive to heavy production, and in 

 some respects it resembles the dry and heavj'-producing 

 districts of Hawaii. Where sugar is now grown in Peru, it is 

 grown under irrigation. Grinding can be continued through- 

 out the year ; in fact, one estate claims that they have not 

 shut down for extensive repairs for si.\ years. At Carnavjo 

 they have been able to recover an average of about 4A- long 

 tons of sugar per acre ; with fully equipped modern machinery 

 this would be somewhat higher. On a piece of land of 85 

 acres, 79'8 long tons of cane per acre, carrying 14 to 1-5 

 per cent, of sugar, have been grown. The canes generally 

 contain a rather high percentage of sugar, 13 to 16 per cent., 

 and high fibre, 12 to 16'-5 per cent. The juices are generally 

 of high density, high sugar content, and good purity ; as 

 high as 23° Brix has been observed, and sucrose 21°; more 

 often, however, the juice will register 20° Brix and 18° 

 sucrose ; in exceptional cases we have noted the sucrose in 

 the juice as low as 1.5°. 



The recent good prices of sugar have encouraged 

 a renewed interest in the sugar industry, and have caused an 

 extra activity in the development of some of the estates. 



One of the chief problems for the advancement of the 

 sugar industry in Peru is the development and conservation 

 of the water supply. Artesian wells have been sunk near 

 Lima, and have so far given a good flow. 



Peru's output of sugar has been gradually increasing and 

 has risen from 71,735 metric tons, in 1896, to 131,975 

 in 1901. The total output for 1905 was expected to exceed 

 143,000 tons. 



Sugar-cane Experiments at Barbados. During 

 the crop period 1904-6 there were 7,739 plots under sugar- 

 cane experiments at Barbados, comprising an area of 87"87 

 acres. There were 172 manurial plots occupying 5177 acres, 

 while 31 '21 acres were devoted to experiments with varieties, 

 which were tried on 709 j)lots. The remaining area was 

 occupied with chemical selection e.xperiments and trials of 

 first- and second-year seedlings. 



-DISEASES OP PLANTS. 



Valuable work has been carried on in the subtropi- 

 cal laboratory of the Bureau of Plant Industry, U.S. 

 Department of Agriculture, under Professor P. H.Rolfs, 

 in connexion with the introduction of tropical and sub- 

 tropical plants, and the diseases to which they are liable. 

 In the following extract from the annual report of 

 the Bureau reference is made to investigations of 

 certain diseases of citrus and other trees : — 



CITRUS TREES. 



Wither-tip. — One of the most serious and wide-spread 

 diseases of citrus fruits, known under the common name of 

 'wither-tip,' is caused by the fungus ColletoirichuM glososjior- 

 ioides. It attacks the bloom, leaf, small twigs, and fruit, 

 and is especially severe upon the fruits of the lemon and 

 grape fruit. Extensive experiments have been conducted 

 during the present year on orchards varying in size from 

 a few trees to 25 acres in extent. The results of this work 

 show that a vigorous pruning of the diseased twigs, followed 

 immediately by a thorough spraying with Bordeaux mixture, 

 is a practical remedy. 



Citrus Blight. — Investigations on the citrus disease 

 known as ' blight ' are being continued. As the diseased trees 

 occur sporadically, preventive means are impracticable, and 

 curative methods will have to be developed. The method 

 now employed by the orchardist is that of eradication and 

 destruction. From what is known of the nature of this 

 disease it is quite probable that curative methods will be. 

 discovered. 



Die-back. — In 1895 the annual loss from die-back was. 

 estimated at $100,000. Vigorous work and careful scientific 

 studies of the cause and cure of this disease have been 

 prosecuted. Now we are able to cure the most stubborn 

 case of die-back at a very small cost, and the annual loss 

 from this disease is exceedingly small. 



During 1905 it was not unusual to find more than 50 per 

 cent, of the trees in a region atfected ; most of which were 

 entirely valueless as fruit-producing individuals. In this 

 indentical region there is now less than one-tenth of 1 per 

 cent, of the green trees aft'ected with die-back. Information 

 regarding the treatment of this disease has been so generally 

 disseminated that no orange grower sustains a loss greater 

 than that portion of his crop which is grown on isolated trees, 

 and orchards containing more than 10 per cent, of trees 

 affected with this disease are now unknown. 



CASHEW BLIGHT. 



A very serious disease of the cashew has developed 

 within the last few years. By means of artificial inoculation 

 the causative fungus of this disease {Colletotrichuiii) was 

 scientifically established during the year. Meantime, methods 

 of controlling the disease were also devised. Thoroughly 

 cutting out the diseased branches, followed by spraying with 

 Bordeaux mixture, proves entirely efficient and practicable. 



MANGO DISEASE. 



During the past decade, the mango bloom has beea 

 attacked bj' a disease which caused most of it to shed. This 

 has been proved to be due to a fungus {Glceoiporiwn mangi- 

 ferae), which also attacks the fruit in all stages of develop- 

 ment. A thorough spraying of the panicles during the 

 blooming season proves to be an efficient and practical 

 remedy. This is a very unusual method of procedure, since 

 nearly all other fruits must not be sprayed in the bloom. 



