280 EErORT OF OFFICE OF EXPERIMENT STATIONS. 



sown<jo ditches and oilier diu-hos in wliich oil could not he offoctivoly 

 applied hy poiirin*; on the surface it was found that j^ood results 

 could he ohtained hv si)rayin^-. \Mu'n applied in that way, tlie oil 

 was found to operate eU'ectively for ahout two weeks. Some of the 

 most extensive experiments with remedies for the control of mos(jui- 

 toas have been carried out at the New Jersey Station." At this sta-. 

 tion a <:reat variety of insecticides were tested. Carbolic acid and 

 cresol were found to be somewhat effective, but were too expensive. 

 Permaniianate of potash was carefully tested on account of the claims 

 which have been set up for this chemical, but Avas found to be. en- 

 tirely inetfective. The cheapest and simplest insecticide for mos(juito 

 larvsc, however, was common kerosene of k)w grade. Crude petro- 

 leum in the ordinary form or in the sohible form was also tested with 

 satisfactory results. xV series of experiments was carried on with 

 sulphate of copper either in simple solution or in the form of Bor- 

 deaux mixture. In all of these experiments it was observed that the 

 destruction of the larva? by copper sulphate Avas a gradual and irreg- 

 ular process. It appears that mosquito larv» are destroyed Avhon 

 copper sulphate is used at the rate of 1 part to every 10,000 to 200.000 

 parts of water. The weakest really efi'ective solution Avas 1 to 50,000, 

 and even then was quite unreliable. No mature larA'^oe or pupa? Avere 

 killed by any strength of the copper sulphate. The addition of salt 

 to AN^ater in Avhich mosquitoes Avere breeding produced no effect on 

 the larva?. Neither quicklime nor chlorid of lime appeared to possess 

 any great value. 



oNew Jersey Sta. Kpt. on Mosquitoes, 1905. 



