THE AGRICULTUEAL NEWS. 



XoVEMBEK 21, 1914. 



INSECT NOTES. 



ANTS. 



In the Annual Report t)n Agriculture and Crown Lands 

 of the C'Olony of Seychelles for the year 1913, under the 

 Iieading Insect Notes, there appear some interesting observa- 

 tions on the life-history of a black ant found in those islairds, 

 :iud the proljable correlation of the spread of scale insect 

 pests with the increase in numbers of the ant. 



It may be remembered that in Insect Notes in the Agri- 

 cultvral News, September 12, 1914, attention was directed to 

 the acrobat ant. a species of Cremastogaster, which has lately 

 become abundant in Barbados, and the connexion between 

 this ant and scime scale insects was noted. The habits of 

 the ant {Techiioritt/iniej' alhipes) under consideration in the 

 Seychelles seem to have much in common with the acrobat 

 ant. 



In the report above mentioned it is stated as proved, 

 tliat this ant is indigenous to the Seychelles, but has only 

 nudtiplied so as to become a trouble.some pest in the last 

 eight or ten years. This is attributed to the development of 

 scale insects, which after the droughts of 1904 and 1905 

 midtiplied to such an extent as to cause the destruction of 

 most of the citrus, hibiscus, and Liberian coflfee plants in the 

 colc>ny. The favourite food of the ant seems to be the 

 excretion of the scale insects, so it is reasonable to infer that 

 mr>re abmidant food supply led to the multiplication of the 

 ants. 



The greatest harm ilone by this special ant would 

 appear to be the increase which it causes in the propagation of 

 scale insects by sheltering them, and protecting them from 

 their natural enemies. A mutual benefit society is thus 

 forured between the ants and the scale insects. The ants 

 [)rotect the scale insects by building a sort of shelter for 

 them on the plants they infest, the shelter being constructed 

 of particles of soil or light vegetable debris: and the scale 

 insects by their excretions supply the ants Avith food. It has 

 even been suggested that the ants actually transport the eggs 

 or larvae of the scale insects from one place to another U> 

 form fresh colonies: this, however, has not been proved. No 

 other great harm is nkced on record against this ant, though, 

 as they infest houses in swarms, ci-awling over eveything, 

 even the food on the tallies, they are a decided nuisance. 

 This ant may, however, be responsible in the future for other 

 forms of injury, such as the destruction of useful kinds of 

 ants, or the dissenunation of disease germs. 



The places most often selected, by these ants for forming 

 a colony, which they do with great rapidity, are the sheathing 

 leaves of the coco-nut, banana, and sugar-cane. From these 

 may be collected specimens in all stages of growth and 

 metamorphosis, by detaching quickly the lea\es infested by 

 them, and .shaking the sheaths over a killing bottle. The 

 workers are, as is usual with ants, somewhat smaller than the 

 males and females, the females being the largest. The 

 •sexual forms are winged, but after the mating flight the 

 females drop their wings, and are carefully tended bj' the 

 workers. 



The ants are chiefly kept under control by the natural 

 agency of heavy rains. During a prolonged shower the 

 water runs down into the .sheaths of the leaves selected by the 

 ants as breeding places, and floods out and drowns swarms of 

 mature ants, as well as eggs. 



As is mentioned above, some West Indian ants seem to 

 have much in common with this species from the Seychelles. 

 Any observations made on ants in these islands and on their 



habits, especially as regards any association of them with 

 scale insects, would not only be interesting, but might be of 

 value in the future, if any species became a danger in any 

 way to the agriculturist. Planters and others are requested 

 to send to the agricidtural officers in each island any oliser- 

 vations which they may make, in order that they may be 

 be recorded. 



Pests of Peas and Beans.— The following, taken 



from Till lierieiv of Applied Entonioloyy, is a review of a 

 pajxi-r by A. S. Kartzov, on the cultivation of peas and 

 I'reneh beans, in Prpffressive Fruit. Gioviiuj and Alartcet- 

 Gardenivg, St. Petersburg, lOl-t: — 



In this booklet the author deals with some of the pests 

 of peas, beans, and salads. Peas are subjected principally to 

 attack by various Bruchidae, amongst which Bruchus pisorum, 

 L. (pisi) is specially mentioned. The females oviposit on the 

 ovaries, and llie larvae live inside, and feed on the seeds, the 

 adults remaining in the seeds through the winter. As reme- 

 dies the author suggests the heating of the infested .seeds to 

 a temperature of 122' F. for not more tlian two minutes; the 

 use of carbon bisulphide; late sowing of peas, so that the 

 beetles should have left them before sowing: trap crops, so^vn 

 from ten to fourteen days previously, on which the beetles 

 will oviposit, the plants being afterwards used as food for 

 domestic animals; heating the seeds in winter to a tempera- 

 ture of 68°F., which will cause the beetles to come out of 

 them; moistening the seeds with lime-water a few days before 

 sowing, and the watering of the beds with the satne water 

 mixed with soot. Kidney and French beans are attacked by 

 Telrani/chus telarius, L., and Aphis radicans; spraying with 

 1 per cent, solution of saltpetre in water at a moderate tem- 

 perature is recommeded against the former, whilst a 1 per 

 cent, solution of tobacco extract is useful against the latter. 



Various salad plants are attacked by insects, amongst 

 which the author mentions, Barathra (Mamestra) brassicae, 

 Ev.roa (Agrotis) sei/etum, Agriotes lineatus and Melolont/ia 

 melohni/ia. 



THE EFFECT OF INSECTICIDES ON 

 CERTAIN PLANTS. 



In view of the likelihood that the cultivation of certain 

 minfir crops may be taken up, if the depression in the cotton 

 market continues, it would seem advisable for experiment 

 station workers and planters generally, to make trial of 

 certain insecticides, in order to learn what effect these exert 

 on the foliage and general health of plants, so that Avhen 

 pests occur they may he dealt with promptly. 



The leguminous plants, peas, beans, etc., are quickly 

 att'ected by certain insecticides. Paris green and London 

 purple injure the leaves of these plants, but it may )>e found 

 that dry powdered arsenate of lead, used without the 

 admixture of lime, is suitable for this purpose. 



Similarly, little is known about the control in the \\'est 

 Indies <>i the pests of pumpkin, cucundier, and squash, beets 

 and tiunips, and Indian corn, and as certainly .some, and 

 perhaps all these will be of more importance in the future 

 than in the past, it would be well to know what remedies to 

 ap|ily in case of an attack of pests. 



In this connexioii it should be remembei'ed that there 

 are two principal groups of insects to be considered: those 

 with biting mouth-parts, and those which puncture the 

 tissues and suck the juices of the plant. 



