378 



THE AGRICULTURAL NEWS. 



December P, 1905. 



Sij^ 



INSECT NOTES. 



Cotton Insects in Barbados. 



The .season of 1905 ha.? been an abundant one for 

 insect.s in general. Cotton fields on certain e.state.s ■n'ere 

 seriou.sly attacked by cutworms which cut down the young 

 plants. The use of a poison bait proved a very efficient 

 check where it was given a thorougli trial. 



On one estate early-planted cotton (.June and July) was 

 so severely attacked that it was thought advisable to replant 

 entirely. A poison I;>ait made of 25 lb. of bran and 1 lb. of 

 Paris green, tlioroughly mixed toc;etber and stirred to a thick 

 mash with molasses and water, was ai)plied, a small handful 

 being used at each hole, and the seed put in at the same time. 

 When the plants grew there was practically no indication of 

 the presence of the cutworm. The cost of this treatment was 

 from 20c. to 2Jl:C. per acre. 



On a few estates the cotton has suffered from the 

 attacks of the cotton worm and a considerable amount of 

 Paris green Las been used. It was early noticed, however, 

 that, even when the leaves of the cotton were badly eaten, 

 very few cateri)illars were to be seen and these were not 

 quite like those of previous years. Many planters also 

 noticed that no pupae were to be found this year, while in 

 previous years in any field where the caterpillars had been 

 plentiful many pupae were found in the leaves. 



Caterpillars were obtained by tlie Agricultural Superin- 

 tendent from estates in different parts of the island and 

 a portion of each lot was sent to the Imperial Department of 

 Agriculture, and as many as possible were reared to maturit}-. 

 From this test not a single specimen of Aletia argillacea was 

 procured, the moths that emerged proving to be all of one 

 kind, but not Aletia arrj'dlacea. Recently, however, a few- 

 specimens of this species have been reared from cater- 

 pillars found in a cotton field in St. Philip's pr.rish. 



The cotton worm of 1905, in Barbados, is smaller than 

 the caterpillar of Aletia argillacea and lacks the character- 

 istic dark stripes along the back. It hides during the day in 

 the bracts at the base of the flower and boll, and the pupa is 

 found in the ground. The moth itself is smaller than Aletia 

 argillacea. The forewings are greyish with greenish reflec- 

 tions, crossed by fine, wavy, light lines and lack the light 

 spots so characteristic in Aletia argillacea: the hindwings 

 are slaty-grey with distinct, light borders. Paris green has 

 been found as effective in dealing with this in.sect as with 

 Aletia argillacea. 



The cotton aphis has appeared in a number of fields, 

 but the natural enemies of this insect have in nearly every 

 case proved sufficiently efficient to prevent serious injury. 



The red maggot has been destructive in only very few 

 instances. On account of the habit of this pest of living 

 and feeding under the bark of the cotton plant, it is difficult 

 to deal with. Cutting out and burning affected plants and 

 branches seems to be the only remedy at present. Great 

 care should be exercised to prevent the plants becoming 

 bruised or broken, as any abrasion of the bark seems to offer 

 opportunity for the entrance of the insect. 



Cocoa-nut Caterpillar in British Guiana. 



A I'L'port by the Government Botanist of British 

 Guiana on a caterpillar which attacks the leaves of 

 cocoa-nut and other palms in that colony has recently 

 been issued. The following is a summary of the 

 rejiort : — 



The insect has been identified from specimens sent to 

 the Bureau of Entomology of the U.S. Department of Agri- 

 culture as Brassolii sojihora, Linn. The eggs of this insect 

 are laid, in batches of 100 to 150 or more, on the stem or 

 under side of the leaves of the cocoa-nut, and have also been 

 found on leaves of other plants. They are smooth, shin)-, 

 pink in colour, nearly round in shape, and about -,}^ inch 

 in diameter. Tlic newly-hatched larvae are about \ inch in 

 length, the full-grown larvae being about 2-1 inches long. 

 They are very voracious feeder.s and their growth is rapid. 

 They are gregarious, feeding and resting together in large 

 numbers. When moving from place to place they move in 

 procession, and when resting are massed closely together 

 with the heads all in the same direction. They have a habit 

 of joining together several leaflets of the palm to form nests 

 in which the caterpillars rest during the day time, and from 

 which they come out to feed at night. 



The pupae are found on the under side of the leaves of 

 the palms affected, and in many other locations where the 

 caterpillars find suitable place to suspend themselves when 

 about to pupate. The pupal stage lasts about a fortnight. 



The butterfly is dark brown in colour, with a broad band 

 of dark orange running obliquely across the forewings and 

 a less conspicuous band of dingy orange on the hind wings, 

 parallel with the outer border. The female butterfly spreads 

 3| to 'i\ inches, and the male 2J to 2J inches. The 

 butterflies rest during the day and fly late in the afternoon. 



The damage done is severe. Many cabbage palms have 

 been killed, while manj' cocoa-nut trees have been stripped 

 of their leaves. The damage is done by the caterjiillars,. 

 which eat all the green parts of the leaf, leaving only the 

 mid-rib and principal veins. 



This insect has natural enemies which may assist in 

 reducing its numbers. Various birds prey on it and parasites 

 of the egg and the pupa have been discovered. 



In dealing with this pest it is recommended that 

 a sharp lookout be kept for the first appearance. The leaves 

 attacked should be cut away and the pocket-like nests^ 

 destroyed. The eggs and pupae should be collected and 

 destroyed, while the butterflies may be collected as they rest 

 during the day on the trunks of the trees. They may be 

 destroyed by burning or by immersing in water which has 

 kerosene on the surface, or in a mixture of water 

 and carbolic acid, or chloro-naiihtholeum. Cabbage palms 

 growing near cocoa-nut plantations should be cut down when 

 the attack is first noticed, as these methods are more difficult 

 to apply to cabbage palms. 



The report concludes with a note, regarding the killing 

 of the eggs, from the Entomologist on the staff of the 

 Imperial Department of Agriculture, who suggested that the 

 following mixture might be useful: creo.sote oil, 5 parts; 

 carbolic acid, 2 parts ; .spirits of turpentine, 2 parts ; coal 

 tar, 1 part. This mixture could be applied to the egg 

 patches with a brush. It is said to have great penetrating 

 power and will kill every egg it touches. 



The writer of the report does not consider spraying, 

 likely to pay, since the cheaper and simpler process of 

 cutting out and burning the nests has been found fairly- 

 successful in dealing with 'he ]:iest. 



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