The Mosquitoes of New Jersey i6i 



The Problem of Mosquito Control 

 General Considerations 



Experience has shown that, until we know more about mosquitoes 

 than is now on record, the most vulnerable point in mosquito life is 

 the larval, or wriggler stage during most of which the creature 

 must live in a water medium. When attack is directed toward this 

 quarter we have merely to eliminate water in which mosquitoes breed 

 and there will be no mosquitoes. This is a beautifully simple state- 

 ment of an exceedingly difficult operation. 



The first problem is the nature of the water in which the econom- 

 ically important species will breed. Are there any aggregations of 

 water in which the economic species will not breed? So far as is 

 known they can not breed in dew because the aggregations are never 

 large nor persistent enough. So far as we know, within the limits 

 of New Jersey, the economic species can not breed in cedar-swamp 

 water. So far as we know, the important fresh-water species can 

 not breed in sea water of over 5 or 6 per cent salinity, nor can any of 

 the salt-marsh species breed in fresh water except as it has been pol- 

 luted. So far as we known, the salt-marsh species can not breed in 

 water of 25 or more per cent salinity. So far as we know, they can 

 not breed in water when both top and bottom working fishes are 

 present (except as the fish are screened away) because larvae, or 

 wrigglers, are eaten before they can reach maturity. 



What kind of water can mosquitoes use? All pools conforming 

 to the following specifications are capable of breeding the economic 

 species of mosquitoes. 



1. Size sufficient to immerse the wrigglers. 



2. Remain at least practically throughout the immature stages (salt- 



marsh 7 days in midsummer to i month in spring and fall ; fresh- 

 water species about two weeks in midsummer to double that or more 

 in spring or fall). 



3. Temperature 55° F. or higher. 



4. Salinity for salt marsh from 4 to 20 per cent and for fresh water 2 



per cent or less. 



5. .Stagnant or very slow moving water. 



6. Absence of wriggler-eating fish or protected by plant screen through 



which the fish can not penetrate. 



7. Not impregnated heavily with mineral acid or the soaking of cedar 



swamps. 



The second problem is the location of the water in which the mos- 

 quito will breed. This is foimd nearly everywhere — sheets of paper,. 



