56 ANNUAL REPOETS OF DEPARTMENT OF AGRICULTURE, 1053 
There have been few experiments in commercial mango orchards be- 
cause of the scarcity of suitable Large plantings in the Hawaiian 
Islands. In the Maui tests, application of a bait spray containing 1 
pound protein hydrolysate, ."» pound- raw sugar, and 1* poind-, para- 
thion 25 percent lettable powder per acre resulted in a 97-percent 
reduction in fruit fly infestations during the 2 weeks 1 period after 
each of three sprayings. The prespray iniestation level was 1.1 larvae 
per pound in fruit picked at the color-break stage of ripeness. Para- 
thion 25 percent wettable powder alone at the rate of LO pounds per 
acre gave 95-percent control. CS 708 plus malathion, 5 and 0.75 
pound-, respectively, of the toxicant per acre gave 93-percent control, 
and 6 pound- of DDT 50-percent wettable powder plus L5 pounds oi 
KI'\ 30 gave 92 percent control. Fly populations in adjacent un- 
treated 3-acre plots were greatly depressed by the spray applications, 
rendering them worthless as bases <>f comparison. Generally, para- 
thion residues from the bait sprays were less than 0.5 p. p. m. one day 
after spraying. The other treatment- applied were more expensive 
and the danger of excessive residues from them was far greater. On 
Molokai, similar results were obtained with bait sprays containing 
parathion. 
DDT residual spray developed for fruit packinghouse interiors 
DDT proved to be the most effective of six insecticides used in I 
to find the best material to apply to interior surfaces of packinghouses 
to destroy oriental fruitflies that might infest fruits during post- 
fumigation packing operations. Where these insecticides were ap- 
plied to nine different type- of surfaces, L0 ounce- of I H >T 75-percent 
wettable powder in 1 gallon of water gave the best results. Residues 
from this spray gave 99.9-percent control of flies exposed to the resi- 
dues on each of the surfaces for 2 1 hour- at intervals during a 150-daj 
period. 
Male oriental fruit fly annihilation effective in control 
A promising new method of orient a 1 fruitfly control has been found 
as a result of further experiments with methyl eugenol. This chem- 
ical is a powerful attractant for the male of this species. By attract- 
ing the male- to poi-oned methyl eugenol feeding -tat ion-, huge 
numbers are hilled before they are able t<> fertilize newly emerged 
females. 
A now developed, this met hod i< the first known successful attempt 
to control an in-ect by annihilation of the male population with a 
»n bait. The method may have even greater value than presently 
indicated in situations where the entire infested area can be treated and 
t he influence of migrating fertile females is remo^ ed. 
The first large-scale test of this method conducted in Opaeula Gulch 
on Oahu wta .one hided in L952 after 28 months of ope rat ion. Guavas 
within tin ' i to i .. mile wide gulch were protected bj 55 poi-oned 
feeding stations distributed for l ' j miles along its rim. Infestations 
in the fruit averaged 76 percent less than the average infestation in 
i urrounding, unprotected gulches. 
Additional information on tin- method of control \\a- obtained 
i- initiated On Hawaii in January 1952. One of the test areas 
quare mile area on the wet Hamakua Coast, extending from 
-cm level up the 3] opes of Manna Kca for 2 ' _. mile- t<> the forest line 
at an elevation of 2,100 feet. The other was a small area of isolated 
