THE MEDITERRANEAN FRUIT FLY. 35 



on spraying prove worth while. Sprays are applied to kill the adults; 

 fruits are destroyed to kill the eggs and contained larvae. 



DESTRUCTION OF INFESTED FRUITS. 



Larvae infesting fruits may be killed by submerging the fruits in 

 water or by burying, boiling, or burning the fruits. The choice of 

 method will depend largely upon the quantity of fruit to be handled 

 and upon local conditions. The surest way to kill all immature 

 stages of the fruit fly is to boil or burn the fruits. Burning the fruits 

 is often expensive and, when trash in compost holes is depended upon 

 to furnish the fuel, the burning operation is likely to be unsatisfactory; 

 for in Honolulu, at least, the amount of fruit to burn is so greatly in 

 excess of the trash that the work is incompletely done. Bringing 

 infested fruits to the boiling point will kill all forms of the fruit fly. 

 Submerging fruits in ordinary cold water for five days will either kill 

 all larvae and eggs or prevent their further development. 



Burial in soil is a satisfactory method, provided the fruit is buried 

 deep enough and afterwards cracks are prevented from developing in 

 the earth above the fruits as the latter decay and settle. It should 

 be remembered that just after transforming from the pupa the 

 adults are so soft that they have the remarkable ability to force their 

 way through incredibly small openings. Hence, a crack in the soil 

 extending down to the fruit, even though it be no wider than the 

 thickness of ordinary blotting paper, is wide enough to permit the 

 adults to reach the surface and so thwart the purpose of fruit burial. 

 Adults can not make their way through 1 foot of well-tamped soil, 

 but because burial or burning is left to subordinates, who may 

 slight the work, boiling or submergence of fruit in water is more 

 highly recommended. 



SPRAYING. 



As adult flies can not lay eggs until 4 to 10 days after they emerge 

 from the pupa, anything that will kill them during this period is 

 useful. Such a remedy has been found in poisoned-bait sprays. 

 These are composed of a sweet substance attractive to the flies, 

 a poison, and water. Mally, who first used a poisoned spray in control- 

 ling this pest, used a formula containing: Sugar, 3 pounds; arsenate of 

 lead, 4 ounces; water, 5 gallons. This he applied at the rate of 1 to 

 1^ pints to each 10-year-old peach or nectarine tree. Lounsbury 

 used 6 pounds of brown sugar, 6 ounces of arsenate of lead paste, 

 and 8 gallons of water. Severin used the Mally formula but increased 

 the poison to 5 ounces. Weinland used 3h ounces of arsenate of 

 lead, 10 pounds of brown sugar, 5 gallons of plantation molasses, 

 and 50 gallons of water. All of these formulas have proved to be 

 efficacious. 



