Vol. I. No. U. 



THE AGRIC'JLTUEAL NEWS. 



215 



Onion growing at Dominica. 



The inteivsting e.\))i.'riiuents on this suhject. 

 described on pnge '2l'i of this nun:hir, atlonl additioiiiil 

 proof of the possibility of growing onions of thoroughly 

 good quality in many of the West Indian islands. 



Volcanic Dust at Barbados. 



Barbados, and St. Lucia liave e.xpericnced a fur- 

 ther fall of volcanic dust due to the last eruption of 

 the SoidViere on the 1.5th. and IGth. instant. Full 

 details are not yet to hand from St. Vincent and 

 St. Lucia. We give on page 217 of this issue some data 

 obtained at Barbados. The total fall would appear 

 to be, approximately, one fourth of that of M.iy 7 to 

 8, varying in places from about one-twentieth of an 

 inch to half this amount or even less. The dust of 

 this shower is possibly of highm- fertilizing value than 

 the May dust, but on this point it is impossible to 

 make any definite statement until the chemical 

 analysis, now in hand, has been completed. 



Insects and Volcanic Dust. 



Advantage was taken of the fall of volcanic dust at 

 Barbados on October l(i, to determine what effect was 

 produced on the insect pests and other insects in the 

 field. Generallj' .speaking the dust had little killing 

 effect on the insects, most of which hid themselves 

 during the actual fall of dust, but were yet exposed to it 

 on the following day when the wind blew it about. 

 From observations made on the following da\-, the 

 greater number of insects escaped unharmed. Two- 

 winged flies suffered severely, there being a notable 

 absence of them after the dust and this aj)]ilies also 

 to the 'cow-bees,' 'wild-bees' and other Hymenop- 

 tera. It is believed also that pond-flies suffered 

 but this is uncertain. Other gnjups escaped practi- 

 cally unharmed and there is no doubt that the dust 

 has had little, if any, effect on the insect pests of 

 Barbados. 



The destruction of two-winged flies and of the 

 cow-bees etc., cannot be regarded as beneficial, as 

 many of these serve to keep catci'j)illars and other 

 pests in check. Whether the great abundance of insect 

 pests during the past months can be attributed to the 

 'JVIay dust' is uncertain, but there is this evidence of the 

 destruction of their enemies and the balance of nature 

 may have been disturbed in this way by the fall of 

 May dust. 



It is an old belief that dust, such as ashes, ]jlaster, 

 etc., is a valuable insecticide, simply because the fine 

 powder is believed to choke the insects. These observa- 

 tions would seem to show that dust, in itself does little 

 beyond killing a portion of the insect life, including the 

 most useful part. The only crop that is likelv to 

 benefit at the present time is the corn, as the dust 

 lodges in the hearts of thej-oung plants and prevents 

 the worms eating into the }"oung leaves. In all other 

 respects the dust may be regarded as having no 

 beneficial effect but jiossibly a harmful one. 



Fruiting of the Mangosteen in the West Indies. 



A ])lant of the Mangosteen {(}ii rci ii'm MaiKjus- 

 fiiiui), a native of the Jlolucca Islands, introduced to 

 the Botanic Station at Dominica, fruited, for the first 

 time last year, and has again borne a few fruits this 

 season. The mangosteen was also introduced at St. 

 Vincent in 1890, but although planted in a favourable 

 situation its growth has been slow and the tree has 

 not yet fruited. 



We might add that the mangosteen has also been 

 successfullv fruited by Dr. Nicholls at Dominica. 



Flies £s Propagators of Disease. 



' An interesting address was given by Sir James 

 Crichton Browne, the j)resident of the Sanitary In- 

 spectors' Association, assembled last week at Middles- 

 brough. Sir James referred to the rule played b}- 

 flies in the propigition of disease. Leaving aside 

 the researches concerning the part played by the 

 A iHipJiclc's in malarial infection, he confined his at- 

 tention to the common house-fly. " This most fearless 

 and audacious of all creatures" is probably the carrier 

 of many \'arieties of bacterial infection. It apj)ears 

 that cultures of many ])athogenic organisms have been 

 obtained recently from the excreta of the common 

 house-fly, Musva ilomcstlca. The role played by these 

 insects in the dissemination of enteric fever in South 

 Africa was referred to, and Sir James remarked that 

 one of the collateral advantages of our campaign in 

 South Africa might jimve to be the opening of our 

 e^es to the part ^ilayed by flies as disease-mongers. 

 The enormous fertility of the ordinary fly forms one of 

 the chief obstacles to its extermination : it has been 

 calculated that one female fly may have 2.5,000,000 

 descendants during one season., {Xatare, August 21, 

 1902). 



Lagos Silk Rubber in Trinidad. 



Mr. Hart writes that he has been testing the value 

 of the rubber fluids, latex, or milk of young trees of 

 Furttamiii chiMiai, Stapf at the Experiment Station 

 at St. Clair, and has found excellent rubber material 

 produced by trees a little more than three years plant- 

 eii. The latex oi' Fa tifamia (ifflcana, Stapf has also 

 been tested, and although found to jjroduce a certain 

 amount of rubber material, yet it is sticky, soft, and 

 decidedly inferior to thepi'oduco oi' Funfumlii I'la/itica. 

 It is ])ossible, however, that its cjuality may improve 

 with the increased age of the trees, as is the case with 

 the Central American rubber tree (CustUloa elantlca.) 

 Specimens of the rubber made have been sent to an ex- 

 pert in England for examination and report. The rubber 

 produced liy Faiifum!<( elasfiea is solid and elastic, 

 resembling 'Para' rubber in appearance and pri:)bably 

 equalling it in quality. 



The presence of trees of the inferior Fantamm 

 africana, at the Experiment Station is of importance 

 as a warning guide as to what shoidd or should not be 

 planted. The two sjiecies were recently determined at 

 Kew from specimens grown at the Trinidad Station. 



