BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 59 
FOREIGN PLANT QUARANTINE ACTIVITIES 
Further safeguards were put into effect during 1949 to strengthen 
our defenses against the invasion of injurious plant pests. The regu- 
lations governing the importation of nursery stock, plants, and seeds 
were revised to give more adequate protection against the introduction 
of such pests with plant propagating material. 
The revision provides for the prohibition of additional specific 
plant material known to be subject to infestation or infection by cer- 
tain insect pests or plant diseases in the country of origin, and for 
the growing of certain material under post-entry quarantine long 
enough to determine its apparent freedom from infestation or infec- 
tion with plant pests not discernible by port-of-entry inspection. 
The preflight clearance of aircraft destined to the mainland, which 
has proved so effective in Hawaii, was extended to domestic planes 
flying from Puerto Rico direct to the continental United States. 
Other Federal agencies, particularly the Bureau of Customs, the Im- 
migration and Naturalization Service, the Public Health Service, 
and the Departments of the Navy and the Air Force contributed 
materially to the program. 
Carriers and Products Inspected 
Plant quarantine activities at maritime ports of entry continued 
on a high level during the year. Prohibited plant material was found 
on 25 percent of the 43,000 vessels inspected. This material origi- 
nated in countries throughout the world, and much of it was found to 
harbor destructive plant pests. Although most of the arriving ships 
came directly from foreign ports, there were 676 vessels from Hawaii, 
222 of which bore prohibited material, and 511 vessels from Puerto 
Rico, 71 of which carried unauthorized material. 
The prevention of the entry and spread of injurious plant pests with 
airborne traffic continued to be one of the most serious problems in the 
plant quarantine program. During the year more than 60,500 air- 
planes were inspected at 51 ports of entry, including 3,679 arrivals 
from the mainland inspected in Hawaii. Approximately one out of 
every four planes inspected carried prohibited plant material which, 
if not intercepted, could have been transported to almost any point in 
the United States within a matter of hours. 
Importations of restricted plant materials under permit — particu- 
larly fruits, vegetables, cotton and cotton products, fibers, cereals, 
and plant propagating material — also continued to be heavy in 1949. 
More than 186,330,000 crates, boxes, bales, bushels, and other units 
were inspected and safeguarded when necessary to eliminate the risk 
of introduction of injurious insects and plant diseases. In addition, 
millions of small lots of restricted plant material entered over the 
Mexican border which required inspection but were not recorded. 
Large quantities of fruits were imported from South Africa and Ar- 
gentina on the basis of refrigeration treatment, and there was an 
increased interest in the importation of agricultural material by air, 
