12 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1 
these puparia a Large number of parasites were reared. Approxi- 
mately L50,000 adult-, representing more than 20 species of parasi -. 
were Liberated by the Territorial Board of Agriculture and Forestry 
iii various Localities in the islands. It is now known that several 
species of parasites are d< finitely established. 
Effective insecticides for oriental fruit fly control developed 
In small plot tests on ixuava. parathion applied at the rate of 
2 pounds an acre at biweekly intervals in a dilute -pray gave 100 per- 
cent control of the oriental fruit fly up to <*> day- after each of 6 spraj s 
and ( JG percent control during the second week. Unsprayed fruit 
averaged 5 Larvae in a pound. DDT at the rate of 1 pounds gave 
94 to 95 percent control; dieldrin at the rate of 2 pounds 97 percent : 
and aldrin at the rate of 2 pounds 8G percent. CS-708 was 90 per- 
cent effective. A bait spray containing raw sugar, 10 pounds, and 
protein hydrolysate, 2 pounds, plus 1 pound of parathion an acre. 
was 81 percent effective when applied to scattered guava t 
In another 14-treatment test on bananas a similar bait -pray for- 
mula, with only 9 ounces of parathion applied per acre, was the out- 
standing treatment, giving a 93 percent reduction from unsprayed 
plots in which infestations ranged from 2 to 24 larvae per pound. 
In semi-isolated gulches, where approximately 28 acres of guava 
were sprayed at 3-week intervals, a bait spray with only 4 ounces each 
of parathion and protein plus 5 pounds of sugar an acre gave ( .*1 per- 
cent control, as compared to 82 percent where DDT was used at the 
rate of 1.5 pounds an acre. Bait sprays utilizing Low concentrations 
of parathion were most effective when used on plots of 2 or more acres. 
In these and other special tests there was further evidence that 
dieldrin attracts ovipositing females from adjacent areas; also that 
it kills the Hies too slowly to prevent some infestation. 
Evaluation made of large-scale fruit fly control experiment on Lanai 
Alter the completion on Lanai of the treatment schedules on 
March 20, 1951, oriental fruit fly infestations remained at exceedingly 
low Levels until September, primarily because of lack of suitable fruit. 
During September and the first 2 weeks in October normal increases 
were noted. These observations confirmed previous conclusions that 
the reduction of flies almost to the vanishing point during the treat- 
ment period was entirely the result of the aldrin. DDT. parathion, and 
Other area control treatments that had been applied, and that with 
< nut in ued treatments cradical ion of an isolated in festal ion is entirely 
feasible. This work has now been concluded. 
Lou temperatures studied OS a means of ridding fruits and vege- 
tables of jnt it fly infestation 
Low temperatures from 30 to I.V I\ were studied as a mean- of 
destroying fruit fly infestation in various commodities. To date 142 
experiments have been conducted with L4,700 fruits and vegetables 
containing approximately 213,000 fruit llies. The number (^ days 
required to kill nil stages of the oriental fruit fly ranged from :> days 
;,i :;n to L0 days at 37 . and from Less than li days at l<» to more 
