IOC 



THE AGRICULTURAL NEWS. 



Mabch 25, 1916. 



INSECT NOTES. 



A BUTTERFLY INJURIOUS TO COCO-NUT 

 PALMS IN BRITISH GUIANA. 



The latest number of the Bulhiin of Entonwloijical 

 Research (Vol. VI, part 3, December 1915) contaiu.san article 

 entitled a.s above, by Lawrence D. Cleare, Jr., F.E.S., of the 

 Biological Division, Department of Agriculture and Science, 

 British (iuiana. The following notes are taken from this 

 article. 



The insect which forms the subject of the jjaper is the 

 Coco-nut Butterfly (Braxso/is sophorae, L.). In 1914 it 

 occurred in unusual numbers in the city of Georgetown. 



HISTORY. 



The first record of this insect in British Guiana is proba- 

 bly that by Schomburgh,in his 'Flora und Fauna \'un British 

 Guiana', 1848, who gave no food plant for it. Within 

 recent years it has been reported in 1905 {OJfirial Gazette, 

 October 28, 1905) from Plantation Grove, near Clonbrook, 

 'where large areas of coeo-nut.s were considerably damaged'. 



It was again reported in 1909, in the Mahaicony district, 

 and from that time till 1914 it was of little importance, in 

 fact it was seldom seem. The outbreaks of this insect, as 

 recorded in the ob.served attacks on coco-nuts in British 

 Guiana, would appear to recur after intervals of four to five 

 years. 



FOOD PL.^NTS. 



The attacks of this pest are not confined to the cocci-nut 

 palm. The common cabbage palm, Oreodoxa o'eracea, is also 

 attacked, and while these palms do not appear to die so easily, 

 they rarely recover satisfactorily, if badly stripped. 



mSTKIiiUTION. 



Little is known of the distribution of BraxsoliK sophonie 

 in British Guiana. As already mentioned, it is known to occur 

 in three districts in the County of Demetara — Planta- 

 tion Grove, the Mahaicony district, and Georgetown: it is 

 reported from Onderneeming on the Essequibo coast, and 

 is stated to have been observed in Bcrbice. It is probable 

 that this insect occurs along the entire coast-lands. 



Outside the cok>ny, it was recorded in Dutch (Juiaua as 

 early as 1705, and in more recent years, from 1904 on, it 

 has been recorded as occurring in Trinidad. 



I.IKE lUSTORV AND HABITS. 



The eggs are laid in masses of from 100 to 150 on the 

 stem and underside of the leaves of coco-nuts and other 

 palms. They are smooth and shiny, pinkish in colour, and 

 cylindrical in shape, and measure about 1 m.m. in diameter. 



The larvae in most cases hatch from all the eggs of an 

 egg mass simultaneously. Newly hatched larvae measure 

 about 4 m.m. in length :iiiJ about .3 m.m. in thi('kness. The 

 liead is large, and out of proportion to the size of the body. 



In colour the head is black to dark reddish brown, the 

 body a light claret-red, with aix light-yellow longitudinal 

 stripes extending its entire length. When full grown the 

 larvae measure about 50 m.m. in length. The Ijody is dark 

 brown in colour, the longitudinal lines being of a dirty 

 yellow. The entire body is covered with soft, short, light 

 coloured hairs. 



The habits of the larvae are peculiar They feed almost 

 exclusively at niglit, resting during the day in long cylindrical 

 pockets or nests tipcn at both ends, which are formed by 

 binding together with .silken tlireads a number of leaflets of 

 the palm. Throughout their larval life they move together 

 in procession, or rest in masses all heading in the same 

 direction. In these nests several hundred larvae collect, 

 with their head.s all pointing in the same direction: a single 



nest may weigh a- much as 2 If). The duration of the 

 larval period is not well known, but it is believed to be about 

 four weeks. 



The pupae are of two sizes, the female which are larger 

 than the male, averaging about 25 m.m. in length. The pupal 

 period lasts about two weeks. 



As in the case of the pupa, the female butterfly is larger 

 than the male. The female measures about 3 inches in 

 expanse of wings, the male from 2"5 to 2w5 inches. 



The general colour of the wings is brown above, light 

 beneath. The forewings above are crossed by a band of 

 yellow or orange yellow. The hind wings of the male are 

 brown above, suft'used with red which is tinted with 

 orange. The hind wings of the female are of a deeper brown 

 with reddish patches near the margin. 



SPREAD OF THE PE.ST. 



A remarkable feature of this (1915) attack by Brassolis 

 was the direction of its spread. Starting at some point 

 to the south-west of the city it spread to the north-east, 

 in a direction directly opposite to that of the prevailing 

 winds. Although practically the whole city suffered, there 

 were blocks in the midst of the affected area that remained 

 untouched. It was observed that palms near the sea were 

 but very slightly, if at all, attacked. 



AMOUNT OF DAMACE DONE. 



The caterpillars devour all the green part of the leaves, 

 leaving only the thiiek midrib and the leaf veins. They 

 pass from leaf to leaf until the entire tree becomes denuded 

 or skeletonized. Trees which are completely defoliated in 

 this way often die as the result. 



N.\TURAL ENEMIES. 



This pest has many natural enemies. The adult insects are 

 captured and eaten by many birds, particularly the common 

 Kiskadee {Pitnni/us sulphuratus); and the eggs and pupae are 

 parasitized. At least two species of pai-asites have been reared 

 from the eggs of this insect, and Chulcis unnulatn has been 

 obtained from the [mpa. 



METHODS OF CONTROL. 



The habit of the larvae of congregating in nests during 

 the day offers the best means of destroying the pest. The 

 nests can easily be seen from the ground, and a boy can be 

 sent up to cut the leaves bearing them, and the larvae can be 

 destroyed by crushing, burning, etc. (,'are should be e.vercised 

 to destroy all the caterpillars, including tliose which are shaken 

 or fall fiom the leaf when it is thrown down. 



H.A.B. 



It having been .shown that a wide range of v iriaticm 

 exists in the alkaloidal content of belladonna plant.s, I'.i ■ 

 work described in Bulletin, No. .10(1, issued from the Bureau 

 of Plant Industry, United States Department of Agriculture, 

 was undertaken to determine whether the characteristic of 

 alkaloidal production is transmissible to the progeny through 

 seed, and whether ihe character is changed by vegetative 

 propagation. The results thus far show that the first gener- 

 ation plants from seed of cross-polinated selected individuals 

 displayed a charactertstic of the maternal parent with regard 

 to alkaloid productivity. Plants were grown from cuttings, 

 and at two stages of their growth these plants showed 

 a marked tendency to display the same characteristic regard- 

 ing alkaloid production as the plants from which they were 

 propagated and the original [jarents of those i)lants. These 

 results are interesting, and it would be u.seful to know 

 whether the same thing applies to the tobacco plant in 

 regard to its nicotine content. 



