296 THE MOSQUITOES OF NEW JERSEY 



Newark Shade Tree Commission) was kept in readiness for spraying. 

 Until 8 :50 p.m. no mosquitoes were noticed flying in. Soon after, two 

 inspectors reported that a number of mosquitoes were alighting on the 

 audience and people were beginning to slap. Close observations dis- 

 closed that they were flying in with the wind from the south side, as an- 

 ticipated, but too high for detection by the inspectors, since it was al- 

 ready getting dark. Apparently repelled by the larvicide fog which was 

 settling low, the mosquitoes rose high above it. Then, attracted by the 

 15,000 persons gathered there, the insects descended into the center of 

 the stadium. The area in the south section of the stadium was immedi- 

 ately fogged with larvicide from a shade-tree gun which threw a stream 

 thirty to forty feet high against the wind. This produced a blanket mist 

 of larvicide drifting with the wind, high above the audience and slowly 

 settling downward. Within a few minutes after it was applied, the mos- 

 quitoes disappeared, and no further annoyance was encountered by the 

 audience for the rest of the evening. At the same time the mosquitoes 

 were very numerous outside of the stadium." 



Dr. Ginsburg (8) presents his conclusions from his work on this sub- 

 ject as follows: 



"Experiments with the New Jersey Pyrethrum Mosquito Larvicide 

 conducted during three seasons, in protecting persons in all kinds of 

 outdoor evening gatherings from mosquito bites, are described. Differ- 

 ent types of sprays were tested. The results thus far obtained indicate 

 that: 



"1. Outdoor areas, such as picnic grounds, stadiums, lawns, and 

 porches can be made practically mosquito-free without injury to vege- 

 tation and with no appreciable discomfort to people. 



"2. On large areas, power sprayers capable of quickly supplying a 

 fine fog, high in the air, are required. 



"3. On small areas, such as lawns and porches, hand pump sprayers 

 or small electric sprayers may be employed. 



"4j. On small porches, centrifugal electric vaporizers can be used, 

 provided that the operation is continuous and produces a constant sup- 

 ply of larvicide mist." 



According to Robert L. Vannote, a practical operator (29) : 



"The application of the repellent is perhaps the least complicated 

 task of the entire operation. Expert knowledge is required to plan 

 where, how, and when to make the application to ensure positive pro- 

 tection before and after dusk without interference or annoyance to the 

 group. 



