BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 55 
in all climatic regions in the county. In many of these regions it 
has shown a rapid buildup and good control in from 8 to 12 months. 
In the States of Morelos, Veracruz. Puebla, and San Luis Potosi 
(Valles) many groves and even entire localities are now commercially 
clear of blackflies because of A. hesperidum. Eighty-five million 
adults of this species were collected and released in infested groves all 
over Mexico during 1952. 
Prospaltella clypealis appears unable to reduce a heavy blackfly 
infestation. Once the infestation is diminished to a low degree this 
species performs well and gives efficient control. It has been released 
in most regions. In some groves in regions such as Colima, Morelos, 
and Valles it has so completely controlled the pest that the latter is 
difficult to find. 
Prospaltella opulenta is established in Valles, Morelos, and Vera- 
cruz. It shows little evidence of being effective in controlling the 
blackfly. 
Fruit Fly Investigations in Hawaii 
Scores of insecticides evaluated for fruit fly control 
Nearly 100 coded materials supplied by Bureau chemists and many 
other compounds furnished by insecticide companies were screened in 
the laboratory in the 1952 program to find promising new fruit fly 
insecticides. Among the coded compounds there were six that war- 
ranted further tests. 
In field tests, methoxychlor wettable powder, applied at the rate of 
20 pounds of toxicant per acre, was as effective on guava foliage for 
19 days after application as 10 pounds of DDT per acre. Each gave 
from 75- to 80-percent kill within 24 hours. The performance of para- 
thion was not improved by the addition of a sticker. Twelve days 
after an application of parathion at the rate of 5 pounds per acre, 
the residues were still 86 percent effective. Isodrin was equal to diel- 
drin in residual effectiveness but neither was as effective as parathion 
until after 12 days of weathering. Malathion and Systox were very 
promising fruit fly insecticides but neither of them had any sub- 
stantial residual action against adult flies after 4 days. Fungicides 
such as wettable sulfur, ferbam, and tribasic copper sulfate did not 
adversely affect the residual toxicity of DDT or parathion deposits. 
In mist blower applications to 6-acre guava plots, parathion was 
three times as effective as lindane when each was used in a bait spray 
at the rate of one pound of 25-percent wettable powder per acre. This 
bait spray also contained 0.5 pound of protein hydrolysate and 2.5 
pounds of raw sugar per acre as the attractant ingredients. Subse- 
quent experiments have indicated that sugar may not be necessary in 
the foregoing bait spray for control of the oriental fruit fly; with the 
sugar omitted the bait spray is highly effective against the melon fly. 
Other recent tests have shown that dieldrin and malathion are effective 
substitutes for parathion in the bait spray but that DDT and CS-708 
are less effective. 
Bait sprays protect mangoes from fruit flies 
A bait spray treatment costing $30 an acre was used to protect a 
mango crop that sold for $750 an acre at the orchard, in tests con- 
ducted in 75 acres of mango orchard on Maui and Molokai, T. H. 
