1 \ ANNUAL REPORTS OF DEPARTMENT OF ACRICUL'I TEE. 1 
ceiling to dired the gas toward each end of the car has eliminated the 
; for fans to circulate the fumigant. 
Among the Large-scale inspection accomplishments in 1949 were the 
certification of L78,000,000 board-feet of lumber, 229,000 Logs and poles, 
cords of pulpwood and fuel wood, L32,000 bales of excelsior, 
and ! units of other forest products. In addition, 26,42 
plants, 418,000 Christmas trees, 568,000 tons and 424,000 pieo 
granite, marble, and -tone were inspected or treated prior to being certi- 
fied for movement from the area infested by gypsy moth. Cert incat ion 
of this materia] required 24,450 calls by 24 district inspectors. 1 
mated valuat ion of cert ified products is $6 1,600,000. 
Incidental to the routine examination for gypsy moths, u 
scouted for PhyUobius intrusva Kono, an introduced weevil known to 
attack arborvitae in several Now England nurseries, and for any 
sibly escaped infestations of the European chafer, now established in 
southern Wayne County, N. Y. 
TRUCK-CROP AND GARDEN INSECTS 
Organic Phosphorus Compounds Outstanding Against 
Greenhouse Pests 
Aerosols containing commercial tetraethy] pyrophosphate or hexa- 
etliyl tetraphosphate with methyl chloride as the propellent gas have 
continued to give spectacular control of aphids, thrips, whitenies, and 
red spider mites in greenhouses. Commercial growers have been using 
these aerosols during the past year with striking increases in produo- 
t ion, particularly during the summer months. In one house alone the 
product ion of roses during the month of August increased from 28,000 
u) 129,000 blossoms, [ncrease in stem length of roses was also notable. 
Reducing the particle size of hexaethy] tetraphosphate aerosols to 
less than 20 microns in diameter made them more effect ive, even though 
this reduct ion was accomplished by decreasing the st rength of the aero- 
sol from 10 percent to 1 percent. It was found that only the particles 
less than 20 micron- in diameter remain in the air more than 4 minutes 
and that the larger part icles appear to be chiefly responsible for plant 
injury and have Little effect on the insects, 
Parathion aerosols have been found especially effective against cer- 
tain leaf tiers, mealybugs, and roaches that are difficult to control. 
They are mm supplement ing aerosols containing hexaethyl tetraphos- 
phate for this purpose. Until more is known about the stability of 
parathion residues, these aerosols should not be used on vegetable 
crop- after the edible parts have formed. 
Several new phosphorus compounds related chemically to parathion 
and tetraethyl pyrophosphate are also highly toxic to various green- 
house pests, lu comparative tests octametnyl pyrophosphoramide was 
found to be the most effective against a resistant -train of the two- 
spotted spider mite, followed in order by tetraethyl bithiopyrophos- 
phate. tetraethyl pyrophosphate, and parathion. Diethyl p-nitro- 
phenyl phosphate and tetraethyl monothiopyrophosphate have also 
been found highly toxic to mites and aphid-. Octamethyl pyrophos- 
phoramide whs found to act a- a systemic poison; that is, when applied 
