312 



JOURNAL OF ECONOMIC ENTOMOLOGY 



Of the many valuable data given, the following are some of the most interesting and 

 important, either as new contributions or confirming the conclusions of earher in- 

 vestigators. 



The flies begin to emerge in New Hampshire some years as early as the last week 

 in June. The maximum emergence is reached the second and third weeks in July 

 and emergence is practically at an end by the middle of August. Egg-laying extends 

 from early July to the latter part of September. Adults may begin to oviposit inside 

 of a week. (It had hitherto been supposed that two weeks or at least ten days was 

 the minimum time between emergence and oviposition.) Efforts were made to deter- 

 mine the average length of time before oviposition but were unsuccessful. This was 

 due to the difficulty of getting adults to act normally in any kind of cage devised 

 The same difficulty made it impossible to determine either the average or maximum 

 length of life of individuals under normal conditions. There is only one brood a year 

 in New Hampshire. (IlHngworth has reported two from New York.) Eggs hatch 

 in from five to seven dsLjs. There is a very high mortahty of eggs or larvse or both 

 in all kinds of fruit. This is least in early apples and greatest in winter varieties, in 

 the latter case often reaching to 100 per cent. Larvse do not leave the fruit, except 

 in rare instances, until after it falls and has become mellow. The maximum issuance- 

 of larvae occurs from infested fruit dropping early in the ripening season. Some of the 

 factors that determine the degree of infestation of one variety compared with another 

 are: early ripening, aroma, and thickness of skin. These factors may act separately 

 or in combination. A small percentage of pupse do not emerge at the ordinary time 

 but remain two winters in the soil, thus making a two-year cycle. This tends to some 

 extent to complicate control measures. Soil fumigants can scarcely be relied upon as 

 a practicable or effective means of control. Cultivation does not control or have any 

 noteworthy effect on the insects. Pupse cannot in orchard practice be buried deeply 

 enough to prevent emergence. Firming the soil would seem to be impracticable as a 

 means of control. Poultry are helpful but usually are not available in sufficient 

 numbers. No kind of bait has been discovered that appreciably attracts the adults. 

 Sweetened poisons sprayed on the trees give very httle indication that they can be 

 relied upon to control the pest. The one great remedy is the destruction of infested 

 fallen fruit before the larvse can escape. The fact that the larvse will not emerge 

 until the fruit is mellow and that the great majority come from early ripening fruit 

 simplifies this means of control. Barnyard stock, especially sheep, hogS and cattle, 

 may be utihzed in the destruction of this fruit. 



Such are some of the most important conclusions reached in this bulletin. The 

 evidence on which they are based seems in almost every case to be satisfactory. How- 

 ever, on the question of the \alue of spraying with sweetened poisons there is room for 

 doubt whether this method was given a fair test. It is clear that the author felt 

 satisfied that all the necessary conditions for such a test had been fulfilled. A careful 

 perusal of his experiments will show, however, that in no case was nearly all or even 

 half of an orchard sprayed, but only from one to three trees, and these were, so far 

 as can be learned, never farther than fifty yards distant from unsprayed trees and 

 usually much nearer. The experiments were planned evidently on the assumption 

 that the flies for the most part do not travel much through the orchard before begin- 

 ning to lay eggs or later. In our work on Cherry Fruit-Flies we at first tried this same 

 manner of testing the sweetened poison with the same belief about the habits of the 

 flies, but soon found that no satisfactory results could be obtained unless we sprayed 

 almost all the orchard. Once this discovery was made we were able to take the 

 worst infested orchards in the province and almost exterminate the pest in them. As 

 the habits of Cherry Fruit-FUes are very similar to those of Apple Maggot Flies, we 



