44 



Provincial Board of Horticultuee. 1897 



Mosquitoes are reported from Kelowna, Spallumcheen Bridge Creek Chilcot.n Fort 



Steele, Port Kells, Mount Lehman, Upper Sumas, Sumas, Hope, Squamish Dewdney and 



Agassiz. Owing to high water in the Fraser River during the past season 



Mosquitoes, and the consequent overflowing of large areas of low-lying land, these pests 



have been more troublesome than usual. Stagnant water furnishes breeding 



places for them, and when it is present on such a large scale, there is no practical means ot 



relief from the insects. l i j 4. „ „„„oirio,.ahlo 



Where the opportunities for breeding are few, they can be checked to a cons^erable 

 extent by keeping cisterns and rain-barrels well covered, and by pouring on the surface ot 

 ponds or marshy places a small quantity of cheap kerosene. The oil spreads 

 Preventives. in a thin layer over the surface, and kills all larvre and pupae present Ihe 

 female mosquitoes are also killed while attempting to oviposit. Unfortun- 

 ately, this method is only applicable to small areas. Where exposure to mosquito attacks is 

 unavoidable, Dr. Smith writes that the following mixture will serve to keep ott the pests:— 



Oil of Pennyroyal I P'^''*- 



Oil of Tar I P^^ts- 



OUve or Cottonseed Oil ^ " 



Mixed together. ■ j- £ 



Rub all exposed parts with this mixture, which will secure exemption tor trom one to 

 two hours, or longer, without renewal, depending upon the temperature and the amount ot 



prespiration. tj. i f 



This may perhaps prove useful to some persons who may only be exposed to attacks tor a 

 short time and who would suffer severely if not protected in some way. 



BENEFICIAL INSECTS. 



It is now generally known that in addition to what are called "injurious insects," those 

 . which cause damage or loss to the fruit-grower and farmer, there are also a 

 Beneficial great number of " beneficial insects," which feed upon or are parasites of the 

 Insects. « injurious insects." 



In this connection Dr. J. B. Smith writes : — " In the course of the ages through which 

 this world has existed there has been gradually established, by the influence of surroundings, 

 a certain ratio between all existing life, vegetable and animal. There is a struggle among 

 plants themselves as to which shall keep the ground, and upon the plants feed animals, includ- 

 ing insects, which form a factor in determining the relative abundance of the different species. 

 With the development of plants their enemies also have developed. One of nature's ways of 

 preventing the plant-feeding insects from obtaining control of and exterminating the plants is 

 to provide enemies of various kinds for them. These enemies in turn must be checked, that 

 they may not exterminate the species they themselves feed upon. Thus there has been estab- 

 lished, gradually and naturally, an elaborate system of checks and counter-checks, by means 

 of which a certain proportion is maintained between predaceous, parasitic, and plant-feeding 

 insects. Under natural conditions this ratio does not change much from year to year. Any 

 interference with this established course is almost certain to be disadvantageous in some 

 direction, and man, in his dealings with natural conditions, has persistently created for himself 

 a series of troubles arising from his own acts. By planting large areas of one crop, he has 

 favoured the increase of insects feeding upon that crop. Man has further disturbed the 

 natural conditions by introducing into new countries insects that have become adapted to the 

 surroundings in others. Sometimes an insect so introduced does not find the new circumstances 

 to its liking ; but on the other hand, it may find them very much better 

 The process of ^j^g^jj ^jjose under which it was originally developed. In such cases we get a 

 multiplication out of all proportion to the normal habit of the species, and 

 there may be destruction of the plants that they feed upon. A fascinating theory in connection 

 with this subject is the possibility of importing parasites or predaceous forms of insects from 

 other countries for the destruction of pests here. 



