242 



forward to in the vor\- near future. It takes many millions of 

 parasites established generally over all areas to begin to do what 

 may be called ettective work, and it takes a year and more often 

 longer to bring about such a condition even if our climatic condi- 

 tions and general environment are suitable for the multiplication 

 of parasites liberated under natural conditions. The leaf hopper 

 pest was not in any way controlled by parasites until the second 

 year after their liberation and the same can be said of the cane 

 borer parasite, which, although established and doing good work, 

 has not yet multiplied to the extent that is required to make it 

 absolutely efi'ective in all sections where it was liberated a couple 

 of years ago. As I have repeatedly informed the r)oard and the 

 press, parasitic work both in tiie field and in the insectary is alto- 

 gether problematical. To be successful the natural conditions 

 similar to those which the parasite has been accustomed to in its 

 native habitat must be as near perfect as possible, and even then 

 the percentage of efficiency of any one parasite may be quite 

 small, in which case it would necessitate the introduction of other 

 species so that all of these combined could bring the parasitation 

 of the pest up to a satisfactory percentage and make relief per- 

 ceptible. The fact that Prof. Silvestri discovered in West Africa 

 at least two other species of fruit fly parasites of a different habit 

 of parasitation from those he successfully introduced here is quite 

 encouraging, notwithstanding the further fact that these two 

 species did not survive the long voyage and changes of climate 

 between Africa and Honolulu. As these particular species are 

 reported by Silvestri to be even more satisfactory than those he 

 introduced here, it is to be hoped that the Board's funds will be 

 such that that entomologist may be engaged for another expedi- 

 tion to Africa next year. In the meantime an entomologist under 

 Silvestri's direction began research work on the horn fly and its 

 parasites along the Mediterranean and vicinity on August 1. It 

 is yet too early to report any results as to this feature of the i^ara- 

 sitic work. 



In conclusion I would su}' that late advices received from Prof. 

 Silvestri indicate that his official report in the shape of a "Bul- 

 letin" will be ready some time next month. As soon as it is 

 received it will be published in bulletin form and distributed. 



^'ours truly. 



W. M. GiFi ARn. 

 President and Executive Officer Board of Agriculture and 

 I'orestrv. 



