330 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol.8 



reduction of infested fruit on those trees that were sprayed. Mally* 

 in 1909, gave a decisive demonstration of the success of this remedy 

 to combat the Mediterranean fruit-fly under South African conditions. 

 '^A severe outbreak of the pest in a commercial peach orchard was 

 brought to a sudden and practically complete halt, and the fruit 

 maturing later w^as marketed under the guarantee of freedom from 

 maggots, . . . while that of untreated trees a few hundred yards 

 away increased until practically every fruit was involved." 



In a series of experiments on the use of petroleum, vegetable and 

 animal oils to trap the Mediterranean fruit-flies, we found that ordi- 

 nary kerosene (about 120*^ Be.) captured more fruit-flies than any of 

 the other oils, with the possible exception of distillate (about 48° Be). 

 As distillate is too volatile for practical purposes it was decided to use 

 traps containing kerosene as- a means of checking up the effectiveness 

 of a poisoned bait spray employed in the control of the Mediterranean 

 fruit-fly. 



When the Mediterranean fruit-flies issue from the pupse, the eggs 

 are undeA-eloped and the adults require from ten to twelve days before 

 the egg- laying period begins. This period may be termed a feeding 

 period and during this time the flies subsist on the waxy coating of 

 fruit, juices of injured fruit on the trees or infested, fallen fruit on the 

 ground. Our attention was also called to the fact that the Mediter- 

 ranean fruit-fly feeds upon flowers of a chrysanthemum imported from 

 Japan, but the pest was not attracted to these flowers in any great 

 abundance. After a rain the fruit-flies were frequenth^ seen lapping 

 up droplets of water on the leaves. In captivit}^ the flies show a 

 fondness for diluted molasses and they would feed on this liquid until 

 their abdomens became greatly distended. The greediness of the 

 adults for sweets is the weak point in the life history of the pest and 

 explains why the sweetened, poisoned spraj^s are so effective in the 

 control of this insect. After the eggs are fully developed in the ovaries, 

 the insect is seized by a reproductive stimulus and then not only seeks 

 a suitable medium in which to deposit its eggs but also continues to 

 search for food. This period, which may be called a reproductive and 

 feeding period, commences at the time the eggs are fully developed and 

 continues until the last egg is deposited. 



In our work the poisoned bait was prepared according to the follow- 

 ing formula, which is slightly modifled from that recommended by 

 Mally: 



BroviTi sugar 2| lb. 



Arsenate of lead 5 oz. 



Water 4 gal. 



