Vol. XVIIl. No 446. 



THE AQRICULTUllAL NEWS. 



171 



and from early in the season swarms were arriving from 

 outfcide ihe country, producing a most serious attack on the 

 cotton plants. At the end of the season, in September, the 

 moths which have been bred in the cotton fields of the 

 Southern States migrate northward, and probably they are 

 joined by others that have come from farther south. 



In the West Indies, the infestation of cotton fields by 

 the cotton worm each year probably arises in the same way. 

 Moths Hying from Brazil or some other section of 

 South America arrive in these islands from time to time on 

 their northward flight, and it is likely that moths bred in 

 the cotton fields here also fly north from island to island, 

 and even to the United States, 



Cotton growers and Department officers in each island 

 should be on the lookout for the arrival of these swarms, and 

 the appearance of the caterpillars in the cotton fields, and 

 should not only take active measures against them, but also 

 record and rep irt such appearances. This method of 

 invasion would seem to provide an explanation of the 

 occurrence of extremely severe attacks at all times in the 

 season, when there have been no preliminary attacks from 

 which the numbers of the cotton worms could have developed. 



Reference to the records published in the l^Vest Indian 

 BuUetin on the Prevalence of Some Pests and Diseases in the 

 West Indies gives interesting information in this connexion. 

 The accounts of the occurrence of the cotton worm in 1911 

 {West Indian Bulletin, Vol. XII, pp.4 14-15) show that this 

 insect was most abundant in October, November and Decern 

 ber, and that the attacks were particularly severe. This 

 attack may be reasonably supposed to have originated from 

 the same source as that which supplied the enormous tllf;ht8 

 of moths in the United States in September. The moths 

 which reached these islands were probably stragglers from 

 the main swarm.i which went farther north. 



The enormous numbers of moths in the flights o^^served 

 in localities far nor h rif the cotton growing regions attracted 

 much attention on the part of people generally. Those 

 who have examined the condi'ion of the moths when cap- 

 tured have niai Veiled at the perfection of the scales and 

 maiking on their w ngs; the condition of the insects is almost 

 perfect when they are taken even in ihe most northern 

 States, and they occur in such numbers at times as com- 

 pletely to cover the surfaces on which they rest, such as 

 brightly lighted shop windows, street lights, etc 



In the discussion which followed the consideration of 

 the cotton woim prcblem at the meeting of the Nevis 

 Agricultural and Commercial Society already referred to, 

 one member present stated tbat on a recent visit to Canada 

 he was on a train which stopped at Sudbury, an important 

 junction. There, much interest was aroused by the enormous 

 numbers of moths which had collected on the head-light 

 of the engine. They were in such numbers as to obscure 

 the powerful head-light sufficiently to make it necessary 

 for the firemin to clear them away. These moths were 

 at once recognized by the gentleman from Nevis as the 

 moth of the cotton worm, with which he was quite familiar 

 as a pest of cotton. 



These northern flights were often observed in past years, 

 say some forty or fifty years ago, but until 1911 they had 

 not been recorded for some time. Since then they have been 

 Been nearly every year, and as noticed above, they were seen 

 in 1918 in Canada by a West Indian planter. 



H.A. B. 



INFUSORIAL EARTa AS A FERTILIZER. 



In the Agricultural News,, Vol. XV, p. 47, an article 

 was published on the US1 of Barbados infusorial ear'h as a 

 fertilizer. In this article thtre were recorded v ry full 

 analyses of a number of these eirth", made by Profe sor 

 Harrison, and reference was made to trials undertaken in 

 Barbados between the years 1883-86 to ascertain whether 

 they would prove beneficial to the crops when applied freely 

 to the land. It was stited that tbe main fact that Pro- 

 fessor Harrison recollects about these trials is that 'the high- 

 ly calcareous earths, from which good results were expected 

 were more or less failures, and the argillaceous earths, 

 characterized by their high retentive power for water, were 

 very succe.ssful, which was quite unexpected. The former 

 remained on the fields in hard, resistant lumps for a long 

 period; the latter rapidly crumbled down, and formed a 

 ''mulching" to the land.' It has not been ascertained however, 

 whether any such trials have been lately made, beyond, 

 perhaps, the occasional use of some of these earths as 

 applications to gardens and vegetable plots, in some instances 

 with good results. 



In ihe course of certain recent inv. stigations Pro'essor 

 Harrison has had occasion to re-examme some of these 

 infusorial earths contained in his collection of gec'logical 

 specimens, and has ob'ained inter sting information concern- 

 ing their powers of retaining water. Ho vrritss as loiiovvs: — 



' In connexion with some recent work I found I had a 

 part of the Castle Grant clay I examined in 188-5. It 

 has been kept in a par ially closed box for thirty- 

 four years. It retains 16 33 per cent of hygroscopic 

 waer. Af er being dried it was exposed to the air in a 

 glass case to avoid dust, and in forty-eight hours its 

 moisture content had risen to 149 per cent., whilst in 

 eight days it rose to 15-5 percent, 



' I also examined some other samples of the Barbados 

 oceanic clays, similarly kept for thirty years, with the 

 following results : — 



Moisture retained Moisture gained after 



Chocolate red clay . . 

 Bright red clay 

 Mottled red and 



cream clay 

 Creamy yellow clay 



'It seems to be fairly certain that the earths, probably on 

 account of the extreme minuteness of their particles, have a 

 marked tendency to retain water, and after drying to regain 

 moisture from the atmosphere. 



'Whilst writing t'lis I have remembered that the late 

 Mr. de Verteuil, of Pdlmiste, Naparima, Trinidad, made some 

 very extensive trials of infusorial earths, from plantations 

 Hermitage, Philippine, and Cedar Grove, as top dressing for 

 sugar cane in the early nineties, I analysed samples of the 

 earths he used, which varied in clay constituents from SO'S 

 per cent, to 3.5'9 per cent., but 1 have never heard tbe result 

 of the trials.' 



The article in the Agricultural Xeivs referred to above 

 states that very satisfactory results in the increase of cro-s 

 were obtained by the use of the Castle Grant earth as a top 

 dressing on fields. It would be very interesting to learn if 

 any planter in Barbados has since made similar trials, and 

 wi'h what results, and also if any record exists of the results 

 obtained in Trinidad, 



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