378 



THE AGRICCTLTURAL NEWS. 



November 26, 1910. 



INSECT NOTES. 



INTRODUCTION OF THE ST. VINCENT 



'JACK SPANIARD' INTO 



MONTSERRAT. 



It has been knovn for some time that the St. Vincent 

 ' Jack Spaniard ' {Polufes anmdnris) is of use in that island 

 in reducing the numbers of the cotton worm (Alahama 

 [Aletia] argillaceu). Recent references to thi.^ matter are 

 contained in the West Indian Bulletin, Vols. VIII, pp. 360 

 and 363: and IX, p. 211. The fact that the cotton worm 

 has caused a large amount of trouble and loss in Montserrat 

 (as indeed has been the case, from time to time, in the other 

 islands in the West Indies where cotton is grown), and the 

 circumstance that this insect is absent from that island, have 

 caused the question of its introduction to be considered. 

 Definite measures have been undertaken towards this, and 

 the insect appears now to be established in Montserrat. 

 Much of the matter that is contained in the follow- 

 ing account is taken from reports on the work of intro- 

 duction that have been received from ilr. W. H. Patterson. 

 Ofiicer-iu-charge of the Agricultural School, St. Vincent, and 

 from Mr. W. Eobson, Curator of the Botanic Station, Mont- 

 serrat. 



Up to October -5, 1910, four consignments of the insect 

 had been received in Montserrat, from St. Vincent. In the 

 first two, pupae were sent; while in the last two, the insect 

 was despatched in the larval stage. In the first case, the uests 

 were simply fastened flat inside the boxes, and the top was 

 covered with mosquito gauze. In the second, as the insects 

 were in the larval stage, an arrangement was made by which 

 the larvae were kept from falling out of their cells by means 

 of rows of wire running from side to side through the boxes, 

 and forming shelves, to which the nests were secured with 

 soft twine; this gave a chance for the more advanced among 

 them to pupate. The additional precaution was not required 

 in the case of the pupae. Here, the pieces of comb containing 

 sealed brood were fixed securely to the sides of the box by 

 means of pieces of tape running through holes in the wood, 

 and fastened on the outside. 



All the consignments arrived in Montserrat in excellent 

 condition. In the case of the first the box was removed, 

 without being opened, to one of the open sheds at Grove 

 Station, and fixed by one of its sides to a beam. When the 

 wire gauze was removed, fifteen perfect insects were found to 

 have hatched out, and the combs showed the presence of much 

 unhatched, sealed brood. Xo immediate disposition to fly 

 was shown by the adult insects: they appeared to be busily 

 engaged in work on the comb. In a few days, the number 

 had increased to fifty; and on August 24, new colonies were 

 being made in different parts of the shed. By October 4, 

 sealed brood was seen in the new combs. An observation 

 of interest was that the shed in which the insects were 

 liberated is quite open, and also that it contains a large 

 number of nests of the local .Jack Spaniard. 



The second consignment was much larger than the first, 

 and was found to contain about 1-^0 adult insects, upon its 

 arrival. It was placed in a large open shed at Dagenham, 

 when the behaviour of the insects resembled closely that 

 which was observed at Grove. At the time of reporting, 

 twenty new combs had been formed, some of which contained 

 sealed brood. The combs in which the insects were imported 

 have been deserted, in the case of lioth consignments. 



The third and fourth importations of the insect were 



sent to Bethel and Elberton: there are no observations to 

 place on record concerning these. All the places where the 

 introductions were made are centres of cotton-growing 

 districts. 



When the leport was made, the cotton worm was only 

 just beginning to appear in quantity in the field, .so that 

 nothing could be said as to any definite attacks on this pest 

 1 ly the imported insect. 



A useful fact, in connexion with the exportation of this 

 insect, is that a box measuring 1.5 inches, culje, will hold 

 about 2.50 nestSj each containing an average of fifteen sealed 

 cells. 



A final matter of interest is that, although Montserrat 

 possesses a Jack Spaniard of its own, this is smaller and 

 less striking in appearance than the species from St Vincent. 



THE COWPEA CUROULIO. 



A bulletin (Xo. 85, part VIII) recently issued by the 

 Bureau of Entomology of the United States Department of 

 Agriculture, gives a very complete account of the cowpea 

 curculio {Clialcodermus aeneus, Boh.). The following facts 

 and suggestions are taken from this bulletin. 



This insect is a small snout-beetle or weevil. The 

 general colour is black with a bronze tinge, the wng covers 

 and thorax being coarsely punctured. The insect is about 

 |-inch in length, and is quite robust. 



The eggs of the cowpea curculio are deposited in the pod 

 or in the forming pea itself, in cavities made by the female 

 beetle by means of the mandililes. The larvae feed inside the 

 pea, or sometimes between the pea and the pod, and when full 

 grown they leave the pod to enter the ground for pupation. 



The insect is said tu be a native of Mexico and the 

 Southern United States. It is a serious pest in certain local- 

 ities within its range, where cowpeas are largely grown in 

 rotation ■\\itli cotton, for not only is a considerable amount 

 of damage done to the cowpeas, but the succeeding crop of 

 cotton may be seriously damaged, or destroyed, by the hiber- 

 nated beetles. Cotton is not a regular food plant for this 

 in.sect, but when it happens that cotton seedlings are available 

 in fields where large numbers of the cowpea curculio have 

 hibernated since the cowpea crop of the previous season, it 

 is forced to eat cotton, as the only available food. 



The curculio does not appear to have been recorded as 

 a pest of cowpeas or cotton in the West Indies, and its habit of 

 leaving the pod to pupate before the seeds are fully ripe would 

 seem to render its introduction, in or with seed for planting, 

 less likely than would be the case with such a pest as the 

 bean and pea weevils (Briielais sp.), which [lupate within the 

 seed. The latter are often transported long distances in seed 

 for planting, and cause enormous damage while the seed is in 

 storage or in transportation. 



The regulations which exist in all the West Indian islands 

 for dealing with imported plants should be sufficient to pre- 

 vent any chance introduction of the cowpea curculio, along 

 with seeds. The pea and bean weevils occur in the West 

 Indies, but repeated introductions may now be prevented by 

 careful fumigation with carbon bisulphide, on the importation 

 of seeds. 



If the cowpea curculio .should be found to exist in a field 

 of cowpeas, a remedy would be obtained in picking all the 

 early pods before they were quite ripe. These would probably 

 contain the eggs from all the beetles, and the later pods 

 would be free from attack. It would also be well not to 

 plant cotton on land which has just previously grown a crop 

 of cowpeas, in which the curculio has occurred. 



