MEDITERRANEAN FRUIT FLY IN HAWAII. 



11 



HOST CONDITIONS. 



Favorable as are the climatic conditions for the establishment and 

 increase of the Mediterranean fruit fly in Hawaii, the host conditions 

 are even more so. Mr. H. J. Quayle, who has studied fruit-fly con- 

 ditions throughout southern Europe, and Mr. J. C. Bridwell, who has 

 had similar opportunities in western and southern Africa and in Aus- 

 tralia, have stated to the writers that nowhere have they found host 

 conditions so favorable for establishment and rapid increase as in 

 littoral Hawaii, especially about Honolulu and Hilo. Under the sub- 

 ject of host fruits, on page 24, the writers record 72 species of fruits 

 growing in Honolulu that are subject to attack by 0. capitata. The 

 discussion of their susceptibility to attack, however, throws little light 

 upon their numerical abundance or upon the seasons of the year 

 during which their fruit is available for fruit-fly infestation. During 

 the clean-culture campaign waged against this pest in Honolulu 

 during 1913, data were secured which forcibly demonstrate the ideal 

 host conditions found in Honolulu, making possible extraordinary 

 increase and excessive infestations. The residents of Honolulu are 

 justly proud of their magnificent vegetation and have taken great 

 pleasure in growing an unusually large assortment of trees and 

 shrubs upon their town properties. An inventory of such trees and 

 shrubs, that bear fruits subject to infestation, growing upon 60 blocks 

 in that portion of Honolulu bounded by Liliha, Punchbowl, Beretania, 

 and School streets, is given in Table III. 



Table III. — Number of host trees and shrubs of the Mediterranean fruit fly growing during 

 1913 in that portion of Honolulu bounded by Liliha, Punchbowl, Beretania, and School 

 streets. 





Lots 



Trees 





Lots 



Trees 





Lots 



Trees 





Lots 



Trees 



Block. 



in 



in 



Block. 



in 



in 



Block. 



in 



in 



Block. 



in * 



in 





block. 



block. 





block. 



block. 





block. 



block. 





block. 



block. 



1 



19 



81 



16 



18 



90 



31 



7 



19 



46 



9 



160 



2 



10 



64 



17 



6 



13 



32 



10 



62 



47 



4 



51 



3 



10 



105 



18 



5 



20 



33 



5 



10 



48 



15 



217 



4 



3 







19 



23 



101 ; 



34 



5 



22 



49 



23 



167 



5 



16 



137 



20 



12 



48 



35 



5 



9 



50 



6 



111 



G 



9 



28 



21 



18 



118 | 



36 



8 



51 



51 



16 



112 



7 



9 



64 



22 



7 



59 j 



37 



14 



134 



52 



9 



41 



8 



4 



59 



23 



3 







38 



13 



108 



53 



5 



65 



9 



6 



18 



24 



14 



75 



39 



41 



115 



54 



14 



83 



10 



9 



124 



25 



3 



8 



40 



12 



74 



55 



23 



112 



11 



28 



132 



26 



M 



25 



41 



36 



135 



56 



26 



158 



12 



6 



163 



27 



4 



7 



42 



17 



76 



57 



12 



37 



13 



9 



66 



28 



4 



15 



43 



18 



208 



58 



4 







14 



9 



66 



29 



9 



42 j 



44 



24 



144 



59 



3 



124 



15 



25 



86 



30 



2 



39 



45 



9 



54 



60 



12 



98 



Total number of lots in 60 blocks, 712; total number of trees, 4,610; average number of trees per lot, 6.5; 

 average number of trees per block, 76.8. 



From this it will be seen that there was a total of 4,610 trees and 

 shrubs on the 712 lots under consideration, or an average of 6.5 trees 

 per dooryard capable of supporting the fruit fly. In Table IV are 

 given data indicating the relative abundance of different hosts. 



