312 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



studied. An efficient spray schedule with insecticides has been deter- 

 mined for the control of this pest. Much additional information 

 concerninfy the life history of the pyriform scale, Protoindvinuna 

 pyrifarmis^ a pest of avocado trees, has been obtained and a report 

 on this work will be prepared in due time. Particular attention has 

 been given to experiments in the control of the papaya fruit fly, 

 Toxotryjyana curvicauda. Several acre plats of papajTis have l^een 

 under observation where various methods of treatment were in prog- 

 ress. The tests have included the use of poisoned baits, barriers, bag- 

 ging, various oils, etc. Several Ijulletins reporting on the work 

 of this project have been issued during the year, as the "Avocado 

 red spider " ; " The avocado, its insect enemies and how to combat 

 them'*; "Insects injurious to the mango," etc. P>xperiments are 

 under way at Homestead, Fla., in developing control for the avo- 

 cado mealybug, also known as the coconut mealj'bug [Pseudococcus 

 vipae). This is a serious pest of the avocado in certain regions. 



In\'estigations of the Mediterranean FRurr fly and the melon 

 FLY. — The work during the past fiscal year at the bureau's labora- 

 tory at Honolulu, Hawaii, may be divided into three general parts, 

 namely, plant quarantine enforcement, Mediterranean fruit-fly para- 

 site investigations, and methods of control of bruchids attacking the 

 algaroba bean. 



The enforcement of plant-quarantine regulations is done in coop- 

 eration with the Federal Horticultural Board, and consists mainly of 

 inspection of fruits and vegetables for shipment to the mainland and 

 supervision over plantations and packing sheds. Details of this 

 work will be found in the report of the chairman of the Federal 

 Horticultural Board. 



The fruit-fly parasitism investigation has consisted chiefly in ob- 

 taining daily records of parasitism by each of four species of intro- 

 duced parasites. These records have been summarized and will show 

 the amount of control exerted by these parasites and the degree of 

 infestation of various fruits by the fly. 



Four species of bruchid parasites have been reared and liberated. 

 They were brought from Texas to HaAvaii in July, 1921, with the 

 result that one of them {Lariophagus texanus) has been well estab- 

 lished in the field, having been recovered from many localities. Much 

 information has been secured on the degree of control exerted over 

 Bruchidae in algaroba beans by an egg parasite, Uscana semifumi- 

 pennis, and a larval parasite, Heterospilus po'osopidis. which have 

 been in Hawaii for some years. 



InNESTIGATIONS of FRUIT FLIES AND OTHER TROPICAL AND SUBTROPI- 



ciAL FRUIT INSECTS IN THE Canal Zone. — Work lias been con- 

 tinued at this field station. Close survey is maintained of injurious 

 insects of the region, especially to detect those recently established. 

 Particular attention was given during the year to the avocado weevil, 

 Ilellipus perseae^ and the avocado-seed insect, Stenoma catenifer. 

 The citrus black fly, Aleu7'ocanthus woglumi, has received major at- 

 tention among the citrus insects, and data are available for a second 

 report on this important pest, dealing with biology and control. The 

 insect is continuing to spread and constitutes a dangerous source of 

 introduction into the citrus States. The insect enemies of the mango 

 ;!nd papaya and the coconut palm have been studied. Attention has 

 constantly been directed to locating as many fruit flies as possible. 



