74 



THE AGRICULTURAL NEWS. 



March 11, 1905. 



INSECT NOTES. 



The Arrowroot Worm. 



This insect lia.s been known for some time as a pe.st of 

 arrowroot, cannas, and tous-les-inois. It oeciir.s in most of 

 the British West India Islands, and in St. A'incent, at lea.st, 

 it has been a serious menace to the succe.ss of the arrowroot 

 crop in certain season.s, and in other places it is one of the 

 worst of the pests attacking the eanna. 



In 1900, a serious attack of caterpillars on arrowroot in 

 at. Vincent was reported, and Mr. .Maxwell-Lefroy made 

 investigations and suggested methods to be employed against 

 th? pest. In 1901, there was another severe attack, but since 

 that time no reports have been received by the Imperial 

 Department of Agriculture of .serious outbreaks. 



In Barbados the canna is infested at all times of the 

 year by the same in.sect, and at certain seasons the leaves 

 present a very ragged appearance wherever seen, which 

 is due to the feeding of this caterpillar. The adult of 

 the arrowroot or canna worm {Cnlfodes etidius) is one of the 

 skippers (family Hesperiidae), that group of the Lepidoptera 

 that conies between the butterflies and moths and pos.sesses 

 some of the characteristics of each. It is, however, usually 

 known as a butterfly. Calpodes efhlins is brown in colour, 

 with angular white spots on the upper and under sides of the 

 wings. The antennae are slender, situated wide apart on the 

 head, each has a thick knob near the end, and is tijiped 

 with a very fine jioint which is bent or curved to the .side. 

 The long hairs on the body and near the ba.se of the wings 

 are reddish brown. The colour is much lighter below than 

 above. The head is broad ; the body is stout ; the eyes 

 are prominent, hemispherical, dark-brown in colour. The 

 skippers take their name from their quick, darting flight, and 

 this insect flies in the .same wa}-, usually keeping near the 

 ground. It feeds on tlie sweets of many different flowers by 

 means of its proboscis, which is coiled under the head and is 

 hardly noticeable when not in use. 



The eggs are laid singly, fastened to the leaves of the 

 food plant. They are greenish-white, ..-'- inch in diameter. 

 These eggs hatch, producing minute caterpillars which feed 

 on the tissues of the leaf. After a few days' growth the 

 caterpillar bends over the edge of the leaf, and fastens it 

 with threads of silk and then lives within the fold thus 

 formed. The larva is greenish in colour, with a tran.sparent 

 skin. The head is reddish, and the segments just behind the 

 head are much smaller in diameter, giving the caterpillar the 

 ajipearance of having a large head and small neck. The 

 full-grown larva sometimes measures 2 inches in length. The 

 pupa is formed within the fold of the leaf and is enclosed in 

 a thin cocoon made of a few pale silk hairs which also lielp to 

 hold it in place. After a few days in the pupa stage the 

 adult emerges and flies away. The butterfly is a day-flyer 

 and may freijuently be seen flitting about and visiting flowers. 



Several remedies have been proposed from time to time, 

 but the use of poisons, such as Paris green and London 

 purple, seems likely to give the best results. These could be 

 used in the same way as in dealing with the cotton worm. 



It is likely that the natural enemies of the arrowroot 



insect have a great deal to do with keeping it in check, and 

 it is only when for any reason it gets ahead of the 

 jiredaceous and parasitic enemies that there is a serious 

 outbreak. In St. Vincent the tick bird iCrof(i}Ji(iga ani) is 

 believed to feed on the larvae, and in Barbados the common 

 blackbird (Quisnihis fortirosiris) has often been observed 

 picking out the larvae from the rolled up or folded leaf. 



For several months it has been noticed in Barbados that 

 although plenty of eggs of CalpoJes ef/i/ius have been 

 consjiicuous on leaves of canna, it has been very diflicult, 

 sometimes impo.s.sible, to find even one caterpillar. This led 

 to the discovery that the eggs are parasitized by a minute 

 insect which eats out the interior, leaving only the empty 

 shell. Sometimes nearly every egg on a plant or in a bed of 

 plants is attacked in this way. It is hoped to publish further 

 notes on this parasite in a future number of the Ar/rictdtttral 

 Keics. 



EPIZOOTIC LYMPHANGITIS. 



Tiie Transvaal Ayrlculftinil Jounud (Vol. II, 

 p. 52) contains an article on Epizootic Lymphangitis 

 among horses and mules in that colony, of which 

 a brief summar}' is given here: — 



Eiiizootic Lymphangitis has appeared in the Transvaal 

 since the war. It has long been known in .several countries, 

 viz., France, Southern Italy, Algeria, Dutch Indies, Japan, 

 and India. 



There are a number of forms of lyniiihangitis, but the 

 one under di.scnssion is caused by the presence of a yeast 

 fungus, Sitrc/inromi/ces farrini moans. The disease first 

 appears in an old wound ; then there appears a morbid area 

 in which the original wound may still persist. Some time 

 after this the flrst ap[>earance of lymphangitis is seen in 

 the swollen lympiiatic ve.ssels and tumours, or buds, as they 

 are called, which usually develop into ulcers. The disease 

 appears first on the legs, but may be transferred to the head 

 when the animal rubs the affected parts. Horses and mules 

 are most often affected in the Transvaal, but it is reported 

 in other places in the donkey and the ox. 



The disease is communicated by direct contact of 

 healthy with infected animals or through the medium of 

 harness, saddle.?, brushes, etc., and the first appearance may 

 not be noticed for perhaps two months after the infection 

 occurs. There is no doubt that, when taken early in the 

 course of the disea.se, cases may be curable, but when the 

 disease is far advanced treatment is rarely successful. 



Badly infected animals should be destroyed as they are 

 a source of constant infection. Sick animals should under 

 all circumstances be separated. No articles used in con- 

 nexion with lymphangitic horses should be used on healthy 

 liorses. Stables, etc., should be disinfected as in the case 

 of glanders. 



A disease among mules and donkeys, bearing the 

 same name, is known in Barbados, Antigua, Martinique, 

 and Guadeloupe. The Barbados disease, however, 

 presents many jioints of ditlerence from the description 

 of the Transvaal disease and it may prove to be 

 a different form of lymphangitis. 



It is recommended in Barbados that, when pens 

 and stables in which diseased animals have been kept 

 are cleaned out and the manure removed, all animals 

 should be kept out and should not be put back until 

 all the manure is taken out, and the ground and floors 

 sprinkled with lime and covered to a depth of about 

 1 foot with fresh soil or mould. 



