12'!: 



THE AGRICCFLTURAL NEWS. 



April 1G, 1910. 



INSECT NOTES. 



THE FLOWER-EUD MAGGOT OF COTTON. 



The Superintendent of Agriculture for the Leeward 

 Islands, Mr. H. A. Tenipany, IJ.Sc , has forwarded to the 

 Imperial Commissioner of Agriculture a brief account of the 

 occurrence of the Hower-bud maggot in Antigua, during the 

 cotton season of 191/910. 



The attacks of the tlower-bud maggot in 1909-10 were 

 remarkable for the manner of their distribution in the island, 

 occurring as they did in several instances on limestone soils, 

 but not at all on those of a volcanic origin. It is also to be 

 noted that none of these attack.s prevented the production of 

 fair crops of cotton, and ISTr. Tempany remarks that the yield 

 per acre is decidedly larger than the yields of the past three 

 years. None of the direct remedial measures that were 

 experimented with gave results. The investigation to find 

 whether cotton could be infested from privet {Clerodendron 

 aculeatum) was without result, because no infested privet 

 could be discovered during the season. In those fields 

 where experiments were laid out with insecticides and 

 fertilizers, the flower-bud maggot did not make its appear- 

 ance at all, and so there were no results to be recorded. 

 Early planting seems to have been of the greatest value 

 in preventing the attacks of the flower-bud maggot. This 

 practice has been strongly recommended each year since 

 the pest appeared, for in each attack the most serious injury 

 has been done in November and December. This may have 

 been because the seasonal and climatic conditions which are 

 most favourable to the rapid increase of the insects happened 

 to coincide with the period when there was the greatest 

 number of flower buds in a condition suitable for attack. 

 The flower-bud maggot may not become a serious pest, under 

 two conditions: (1) that cotton is planted early — say 

 in May or June; (2) that the weather conditions later in the 

 year are such that the insect does not appear until a sufficient 

 number of buds has developed to ensure a good first picking. 

 The conclusion to be arrived at from past experience seems to 

 be that the future of the cotton industry in Antigua depends 

 on the ability of the planters to get seed planted early, in 

 order that the flowers to make the first picking may be suffi- 

 ciently advanced not to be liable to attack when the condi- 

 tions become most favourable for the insect. This favourable 

 season seems to be between the middle of November and the 

 middle of December, and it is likely that any buds that 

 open before that time will escape the attack. 



THE SCREW WORM. 



In 1902, the screw worm, which is the larva of a fly 

 {Coi/ipsomyia mncdlaria) was so abundant in the island of 

 Bt. Lucia, in 1901-2, as to be a .serious pe.st, and a pamphlet 

 was published by this Department (Pamphlet Series, No. 14), 

 giving an account of the appearance and habits of the insect 

 and of the remedies to be used against it. The screw worm 

 develops into a fly similar in appearance to the bluebottle fly; 

 it is about the size of the house fly, or a little larger, of 

 a metallic blue or green colour, and it is marked on the dorsal 

 surface of the thorax with three dark longitudinal lines, ex- 

 tending from behind the head to between the wings. 



The egg is white, cigar-shaped, and several of them are 

 generally glued together in a bundle, when laid. They are 

 larger than the eggs of the house fly. They hatch in one to 

 forty-eight hours. The maggot is a white, footless worm-like 

 creature, tapering almost to a point in front, and ending 



bluntly behind. At the hinder end, there are two dark 

 spots — the openings of the breathing apparatus, which are 

 placed in this way in order to allow the maggots to bury 

 themselves in the flesh of an animal, and still to breathe 

 the outer air. The full grown maggot is from i-to J-inch 

 iu length. This stage lasts from seven to ten days. The 

 pupa is browpish in colour, oval in shape, seed-like in 

 appearance, aiid about J.-inch in length. The pupal condition 

 lasts from fourteen to tvi-enty-one days, after which the fly 

 appears. The screw worm is of importance from its habit of 

 infesting wounds and open sores on domestic animals. The 

 female fly lays its eggs in these places, and the maggot feeds 

 on the flesh, thus increasing the depth of the sores. Such 

 infested wounds and sores, left without care and attention, 

 are very likely to cause the death of the animal. 



In treating the wounds attacked by the screw worm, two 

 objects are to be aimed at: the removal of the maggots, and 

 the disinfection of the wound. The sooner that treatment can 

 be commenced after the wound is made, the better the chances 

 for successful results. The first step in dealing with these 

 attacks is thorough cleansing of the wound by washing with 

 clean water, which should be warm, if possible; the next is 

 the removal of any maggots that can be seen; finally, a suitable 

 dressing is applied. An examination should be made after 

 about 12 hours, for the removal of dead maggots and the 

 renewal of the dressing, in order to promote healing and to 

 prevent blood poisoning. 



There are several good dressings which may be used for 

 the purpose. Equal parts of carbolic acid and sweet oil may 

 be applied to the wound to kill the maggots, and as a disin- 

 fectant. Carbolic acid alone, applied carefully, or .Jeyes' fluid, 

 may be used for the same purpose. Tar is useful for covering 

 fresh wounds and cuts, to prevent the access of the flies, or 

 for keeping flies away from wounds which have had the 

 maggots removed and have been dressed. Fish oil is also 

 useful as a repellant for the flies. 



A short time ago, a correspondent in Barbados sent 

 a flying fish attacked by maggots to the Head Office of this 

 Department. The maggots were found in the flesh of the 

 fish, which was firm and healthy, within a few hours after 

 it was caught; they were nearly full grown, and must have 

 been four or five days old. Specimens were sent to the 

 LTnited States National Museum, where they were identified 

 as: ' Probably Chrymmi/la, not the screw worm {C .ludcellaria) 

 but closely allied thereto.' This is an interesting case of 

 ]iarasitism, and it is difticult to understand how the fly — the 

 parent of the maggots— found opportunity to deposit eggs in 

 or on the body of the fish. It might be po.ssible that the 

 eggs were laid in the bait, which is prepared on shore, and 

 that the maggots, lieing swallowed by the fish, were able to 

 penetrate into the fleshy parts and live and grow there. 



The group of flies to which the screw worm belongs is 

 of wide distribution, and its members, at times, become very 

 abundant. The screw worm fly has been classified in at least 

 three dilferent genera {Compsoniyia, Luci/ia and Chri/soini/ia) 

 and under some twenty-seven different specific names. It 

 attacks ordinarily all domestic animals, and there are species 

 which are found on various wild animals; cases are on record, 

 even, of attacks on human beings, a large proportion of which 

 proved fatal. The range of hosts is even greater than this, for, 

 in addition to the case of a related insect attacking the flying 

 fish, which has been mentioned above, larvae of a species of 

 Liicilia have been found in living and newly dead toads, and 

 one of the bluebottle flies (Lwilia caesar) has been observed 

 depositing eggs in a living nestling of the mistle thrush that 

 had fallen from the nest. 



