BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 25 
and fairly well with a wettable sulfur-parathion combination. Both 
combinations have also given good control of the citrus rust mite. 
In California sprays containing 1 to 2% pounds of 25-percent 
parathion wettable powder per 100 gallons were satisfactory against 
the citrus red mite only when oil was included, when they held it in 
check between spring and fall applications. Aerosols containing 
acaricides applied under fumigation tents gave poor results in Cali- 
fornia. A yellowing and dropping of lemon leaves sometimes fol- 
lowed treatment with parathion alone or in combination with oil 
emulsions. 
Pineapple mealybug 
In tests conducted in Florida near Fort Pierce and North Miami, 
parathion dust was effective against the pineapple mealybug, the in- 
sect responsible for wilt disease of pineapples. Plants treated with 
a 1-percent dust at the rate of 0.85 ounce per plant were free of 
mealybugs for as long as 4 weeks after treatment. In another test 
0.15 ounce per plant was not so effective as the heavier dosage, but 
a great reduction in the number of infested plants was evident for 
11 weeks. Two applications of 0.16 and 0.24 ounce per plant 1 month 
apart were no better than one application of 0.16 ounce. 
Only 0.01 part per million of parathion was found in samples of 
unpeeled whole pineapples 7 weeks after applications of 0.48 ounce 
per plant, and none was found in the flesh. None of the treatments 
were injurious to pineapple plants. 
Grape insects 
In tests in Ohio good control of the grape berry moth was obtained 
with V/ 2 pounds of 50-percent DDT wettable powder, with 2 or 3 pints 
of 25-percent DDT emulsion, and with 1 pound of 25-percent parathion 
wettable powder per 100 gallons, when applications were made at 
petal fall and in four cover sprays. Damage to berries by first-brood 
larvae was held to 3.2 percent or less and by second-brood larvae to 
2 percent or less. DDT at y 2 - and 1-pound concentrations of 50-percent 
wettable powder seemed to be less effective than at iy 2 pounds. In 
tests with a dust containing DDT and the fungicide ferric dimethyl 
dithiocarbamate, 12 applications gave control about equal to 8 spray 
applications. When first-brood control was omitted, 2 or 3 applica- 
tions of a 5-percent DDT dust or 2 applications of a 2-percent para- 
thion dust did not give acceptable control of the second brood, but 6 
applications of a 5-percent DDT dust did give good control. 
Parathion Promising for Control of Scale Insects 
There are indications that an effective substitute for, or supplement 
to, oil for the control of scale insects on fruit trees has been found in 
the new insecticide parathion. 
Experimental applications of parathion, as used for codling moth 
control in Indiana and for curculio control in Georgia, were extremely 
effective against the Forbes scale on apple and the San Jose scale 
on apples and peaches. The minimum effective dosage for control of 
these scales has not been determined, but one-quarter pound or more 
of 25-percent parathion per 100 gallons in six applications or one-half 
pound in three consecutive applications gave complete protection to 
