29? 



THE AGRICULTURAL NEWS. 



Skptkmber iJO, 1919. 



INSECT NOTES. 



FOOD OF TIPHIA AND CAMPSOMERIS 

 Soil grubs similar to ihe brown hardback srubs which 

 occur as pests in the AVest Indies are the cause of much loss 

 to planters in C^ueens'and. In the Qiiecns/aiid Ai;ncul- 

 itna I Journal for .luly 1919, there appeared inieresting 

 notes on the subject of cane grub investigations, by 

 Dr. J. F. I'.lingworth, Entomologist on the staflF of the 

 Bureau of Sugar Experiment Stations. 



Rtferring to the importance of nectar-producing plants 

 in cane areas, the author mentions the flower-visiting habits 

 e' the parasitic wasps of the genus Campsotceris, which 

 attack grubs of several kinds. In the West Indies, 

 Campsomeris is the parasite of the ordinary or black hard- 

 back, and ic is one of the most frequent of tlower visitors in 

 those districts where it is abundant. On the othtr hand, 

 Tiphia parnlkla the parasite of the brown hardback, is net 

 a Hower visitor. In Barbados it feeds on the sweetish 

 secretions of aphides. In St. Kitts it has been observed 

 on the dower-buds of the Horse bean (CaJiavalia ensiformis), 

 where its actions indicated that it was feeding. 



In recent attempts to introduce Tiphia into Mauritius, it 

 was found that the success of the final attempt was achieved 

 only because of an abundance of the plant Cordia iiilerni'^ta, 

 which develops vesicular hairs containing i^ectar. Dr. 

 Illing worth refe's in his notes to Tiphia in Mauritius 

 feeding un the flowers of Cmdid interrupta, and includes 

 this insect among those which would beiaetit by an increase 

 of nectar producing plants in cane areas. That author 

 suggests i'l*n'ifg Tigeon pea {Cajamis indicus), and the 

 Bonavist (Doiichm Lablah) along borders of cane fields in 

 order that the nectar from their flowers might serve as 

 food for parasitic wasps. 



In Barbados, Cordia inter nipta'vi'hdvag grown for this 

 purpose, and it is particularly useful because it produces nectar, 

 not in flowers, but in its vesicular hairs. There are possibly 

 other plants which, like this and the Horse bean, furnish 

 food lor adult Tiphias which though depending on sweetish, 

 nectar-like substances for food, do not care to visit flowers 

 to get it. 



In districts where the brown hardback griib^ are 

 troublesome as pests of sugar-cane and maize, it may be 

 possible to increase the numlaerof parasites by providing the 

 adults with abundant sujiplies of food. This should help to 

 attract them to the distri<-ts where grubs are abundant, and 

 also assure them plentiful supplies of food during the period 

 of mating and egg-laying 



Throughout the West Indies it has long been a practice 

 to grow pigeon peas on the hcadrows along the borders of 

 cane fields, and the bonavist is also of fre(|uent occurrence. 

 Under Barbados conditions where wild flowering plants 

 are not abundant, it may be that these have, been useful in 

 furnishinf{ food to the parasites of the hardback grubs. It 

 Hhould be remembered, however, that while nectar producing 

 flowers would be valuable in providing food for parasitic 

 ■wasps of the genus Cinipsoraeris, it is necessary to tind 

 extra floral nectar for insects of tiio genus Tiphia as supplied 

 by the vesicular hairs of Cordia and similar material pro- 

 duced by other plants, or similar sweetish substances such 

 as the honeydew j roduoed by upbides md other plant 

 sucking insects. 



Jl.A.B. 



INSECTS ATTRACTED BY SMOKE. 



In the Canadian Entomologist, May 1919, an article 

 appears on popular and practical entomology entitled. 

 'Fragments in i he Life Habits of Miuitoba In.sects'. In 

 this the author, .Mr. Norm»n Criddie, of the Dominion 

 Entomological Laboratory, Treesbank, Manitoba, gives some 

 very interesting notes. 



An iccount is given of the means found u.seful for 

 attracting a very handsome day flying moth Most of the 

 larger moths are night fliers, and many of then: can be 

 attracted to lights. With day flying moths, however, light- 

 traps are of no avail. It was found in the case of t' e buck 

 moth {Ihmiicuca liici/ia, var. I'jfi/asciatii, B. and Mc. D.) that 

 smoke provided the necessary attraction. A small fire was 

 built of dead grass and leives making a smudge which 

 would send its smoke down wind for i-mile or so. The 

 motha were soon seen beating up wind, making direct'y for 

 the fire, i.e., the source of the smoke. It was noted, however, 

 that only male moths were attracted by the smoke. 



.'.nother portion of the article deals with the housefly 

 and gives an account of the attraction of the smoke for this 

 insect. The following is ^^^^uoted : 'Our first experience with 

 the house fly as attracted to camp-fires was many years ago. 

 We thought then that it w .s the savoury smell of a roasting 

 grouse that induced the gathering, and I am not prepared to 

 say even now that this was not, in part, the case. Later, 

 however, we discovered that the flie.s came almost, if not 

 quite as readily, when no cooking was in progress. But the 

 climax was reached when we attempted to drive the pest 

 from a building by smoking it out, and after being forced 

 out ourselves and permitting the smudge to modify, found to 

 our astonishment that the flies were thicker than ever 

 inside, as if waiting a promised feast. It seemed to matter 

 little where the fire was started, be it in the wilds ' far 

 from habitations, or close roan. I the farm yard, the 

 smoke no sooner had time to spread than ^long came 

 a huuse-fly, and soon a small procession was seen rapidly 

 beating "up wind.' 



'I'nlike the moth described above, the flies did not fly 

 directly into the fire, bu'. instead, seemed to use the smoke 

 merely as a guide that led to objects more Kttractive. 

 Further observations convinced us that smoke constituted an 

 invariable attractant for these insects. We also noted that 

 a frequent method of entering a house, namely, by means 

 of a chiii.uty, wus only utilized when a fire provided the 

 necessary smoke, and not to any noticeable extent when heat 

 alone issued forth. 



'Thus the contention that the attraction was in 

 reality heat and not smoke, does not seem to be warranted 

 from this evidence, and while the gatheri'ig of flies around 

 screen doors and windows is doubtless, in part, due to 

 warmth, it may also be largely influenced by the smells from 

 within, including smoke. Our experiments in the field, in 

 which we provided a maximum quantity of smoke with 

 a minimum amount of heat, in every way confirmed our 

 previous observations as to smoke being the true cause if 

 the attraction. It miKht be asked why should flico be 

 drawn i i smoke and follow it to its source '. What does 

 smoke usually foretell '. A hibitation or camp fire, and these 

 in their turn, man and food Is it not possible that this 

 reasoning acquired from long association with mankind, has 

 become p'rt of the (ly's instinctive nature ' It .seems so to 

 ine, but I am content to let others judge. In any cas", 

 there are opportunities (or some interesting experiments 

 alorg the lines i if this study which would seem well worth 

 while' H.A 15. 



