CONTROL OF ARGENTINE ANT IN CALIFORNIA. 



15 



of ants but their effectiveness was lost upon exposure to the 

 weather. Once wet these insecticides are valueless. These powders, 

 especially the pyre thrum, singly or in combination with the sodium 

 fiuorid, are decidedly repellent to ants and quickly cause death 

 once they come well in contact with their bodies. The fact 

 fhat their strength is soon lost on exposure to air restricts their 

 usefulness. 



The following experiments demonstrate the comparative efficiency 

 of these substances used singly or in combination. Breeding cages 

 containing a large amount of mealybug-infested lemons and potato 

 sprouts were heavily attended by ants which entered in steady 

 streams along the legs. The legs were set in tops of fruit jars contain- 

 ing a small amount of sodium fiuorid powder. Ants continued to 

 cross in limited num- 

 bers for about one 

 hour before the trails 

 were completely bro- 

 ken up. No dead 

 ants were found. 



Pyrethrum powder 

 was sprinkled about 

 the legs of one cage, 

 stopping the trails 

 almost immediately. 

 Dead ants began to 

 pile up in the powder 

 and on the floor about 

 the powder. 



A mixture contain- 

 ing pyrethrum 1 part, 

 sodium fiuorid 7 parts, and plaster of Paris 2 parts, was dusted 

 about the legs of a breeding cage attended by ants with effects 

 about as satisfactory as with pyrethrum alone. 



Corrosive Sublimatk Ant Bands 



Corrosive sublimate has long been known to possess merit as a 

 repellent to ants and this fact has been utilized in protecting materials 

 from these pests. A common method is to soak narrow strips of 

 cloth in a saturated solution of this chemical and use these as barriers. 

 The saturated solution is best prepared by heating about H ounces 

 of corrosive sublimate in an ounce of water until the maximum 

 amount is dissolved. The solution is then allowed to cool, is filtered, 

 and the cotton band or tape is soaked in it for several hours. The 

 tape is then removed, allowed to dry, and is ready for use. This 

 amount of solution is sufficient for from 10 to 12 3 ards of ^-incli tape. 



Fig. 6. — Repellent ant powders: a, Pyrethrum: b, pjTethrum 30 per 

 cent, sodium fiuorid 70 per cent. Shaker and blower for applying. 



