42 



THE AGRICULTURAL NEWS. 



February 8, 1918. 



INSECT NOTES. 



SUGGESTIONS FOR MOSQUITO CONTROL 

 IN A WEST INDIAN ISLAND. 



I A'o/di from, a report to the Imperial Commissioner of 

 Agriculture bv the Entomologist '/ this Depurtment after a 

 visit to Grenada.'\ 



At the request ol the proprietor of a certain estate 

 I went to see what advice could be offered in connexion with 

 moEquito control. The managers and their families on this 

 estate have suffered to such an extent from malaria that the 

 proprietor desires to take such steps as may be necessary to 

 render the place free from this disease, and to protect the 

 managers and their families from attacks by the malaria 

 mosquitoes I did not collect mosquitoes, but merely went 

 over the place with a view to advi.sing as to mosquito control. 



Mostjuito control with a view to the preventing of 

 malaria falls under two general heads : — 



(a) Prevention of attacks of mosquitoes. 



(bi Elimination of mosquitoes from the vicinity of dwell- 

 ing places. 



In discuss-ng the siluiiliou i recommended mosquito- 

 prooling the manager's house with suitable wire-gauze. For 

 thi.s purp"5e brass or copper wire-ganze, 20 mesh, would be 

 most satisfactory. 



The manager's house in 'Hiestion might be easily 

 screened. In order for such screening to be effective, all 

 doors, windows, ventilators, and similar openings should be 

 screened, and any cracks, knot holes in the lumber, or similar 

 sccidental apertures should be carefully covered. Screen 

 doors should be provided with springs for closing them 

 imiried lately, and with a spring catch to fasten and hold them 

 shut- The kitchen should be screeqed also, with a screen 

 door between the kitchen and other parts of the house. 



The anopheles mosquito Hies from ju.st before sun- 

 set to about sunri.se, and during this time every precau- 

 tion -should be taken to prevent the entrance of mos- 

 quitoes into the house, and to prevent mosrjuitoes from 

 biting. The u.se of mosquito netg for protection against 

 mosquito bites during sleep is well understood in the 

 "West Indies. Mo.sijuito nets should not be discariJed even 

 after 'he dwelling house has been 'mosquito proofed', until 

 it is found that no mosquitoes are gaining access to the 

 sleeping room. 



" The.se mo8<iuiloes rest during the day; in the house they 

 seek out dark corners and obscure patches on walls and ceil- 

 ings, where they remain motionless during the day. They 

 hide behind the curtains or clothes, and get into closets 

 and wardrobes, the drawers of bureaus, under tables, and, in 

 fac; in any spot sheltered from light and currerits of air 



The interiors if rooms, where the atteni[)t is being made 

 to get rid of moscjuitoes, .'■hould be painted or washed in li^ht 

 colours — as light as jOTSfjible without making the effect too 

 clary tor th<* comfort of those who occupy them. Curtains 

 als" and nilicr liangintii t hould hf dixpensed with a-' far as 



possible, and clothes and all wearing apparel should be folded 

 and put away during the day, or, if hung up, should be placed 

 in bright light, and if possible in a draught of air. 



The object of a light paint or wash in the room is to 

 make it easy to capture any mosquitoes which may have 

 gained access during the night, and which have taken refuge 

 for the day in shady spots on the walls or ceilings. The 

 mosquitoes being dark in colour are more easily seen on a 

 lightrcoloured surface. The reason for hanging clothing in the 

 light, and in a draught of air is that the mosquitoes seek 

 secluded places in the daytime, and on the advent of daylight 

 move away from the light and airy parts of the room to the 

 more shady and still retreats. 



If wardrobes, presses, closets, and chests of drawers are 

 found to harbour mosquitoes during the day, they should be 

 examined, and the mosquitoes captured and killed. Mosqui- 

 toes resting on the walls may be killed by means of the 

 ordinary lly 'swatter,' a pieee of wire-mesh about 4 by ."> inches 

 in size, fixed to a slender wooden handle 16 to 18 inches 

 long. The ordinary insect net, made by fixing a muslin 

 bag on a wire ring about 10 inches in diameter, attached to a 

 light wooden handle 4 feet or so in length, may be found useful 

 for catching mosquitoes in the house. 



^Mosquitoes resting on the ceiling may be captured in the 

 following manner. A shallow tin or glass receptacle i to | inch 

 in depth is ti.xed at the end of a light pole, of sufficient 

 length that the ceiling may be reached with it. A small 

 amount of kerosene oil, or oil and water, is put into this 

 receptacle, which is carefully raised up and placed over (or 

 under) the mosquito. The insect attempts to fiy, and is 

 caught and killed in the oil. 



There are many repell!>nt oils and mixtures which may be 

 rubbed on the hand, face, and exposed parts, which prevent to 

 some extent the attacks of mosquitoes. They are most likely 

 to be of use in situations where mosquito nets are not 

 available, or for application during the evening before 

 retiring for the night. They cannot be expected to take 

 the place of good mij.5ijuito nets, but in the case of nets 

 in a bad state of repair they may be useful. .Spirits 

 of camphor, citrcmella oil, oil of lavender, oil of penny- 

 royal, oil of tar, casjia' oil, essential oil of oranges, and 

 many other aromatic substances are all useful in this con- 

 nexion. An objection to all these is that they evaporate 

 more or less rapidly, and often only give protection for a 

 part of the night. Several mixtures are strongly recom- 

 mended, and some of these are said to retain their repellent 

 qualities for a longer time than any of these substances 

 when used alone. A few of these mixtures are indicated 

 herewith : — 



(a) Oil of citruiiclla 1 oz. 

 •Spirits of ciinphor 1 oz. 

 'L)il of cedar \ oz. 



< )rdinarily a few drops of this mixture on a towel hung 

 at the head of the bed will be sutticient to repel mosquitoes 

 from the face of the sleeper, liut if mosquitoes are very 

 abundant it may he necessary to rub a few drops over the 

 skin of the hands and fice. 



(b) Castor oil 1 oz. 

 Alcohol 1 oz. 

 Oil of lavender 1 oz. 



This mixture has l>een prepared to avoid the use of 'Mtro. 

 nella, which is very objectionable to many persons. 



(c) ( )il of citroneila ' 1 oz. 

 Liquid vaseline 4 oz. 



The citroneila in this ointment may be replaced by other 

 oils if 80 desire<l. 



U. A. R. 

 (To be (0)1 tinned.) 



