70 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 11 
the basis of results obtained in earlier small-scale experiments, isola- 
tion of the gyptol was undertaken from the combined, partly purified 
materia] recovered from 98,500 abdominal tips of female moths. A 
product was obtained thai was shown to consist of a mixture of gyptol 
and a closely related substance. A small quantity of gyptol has been 
obtained in a state sufficiently pure to crystallize. 
FOREIGN PLANT QUARANTINE ACTIVITIES 
.">0.000 Unauthorized Airborne Plant Shipments Intercepted 
Entry of pests in airborne traffic was prevented through the work 
of plant quarantine inspectors stationed at 50 airports throughout 
the continental United States, Hawaii, Puerto Rico, Alaska, and 
Guam. In cooperation with the United States Customs they in- 
spected aircraft, their stores, quarters, and passengers' baggage for 
restricted or prohibited plant matt-rial that might carry injurious 
pests. Interiors of planes were examined for living insects that 
might be present. Airborne cargoes and air mail were also 
examined. Planes leaving Hawaii for the mainland were given com- 
plete plant quarantine clearance prior to departure and sprayed 
with an aerosol containing DDT to eliminate fruit flies or other pests 
that might be present as stowaways. This practice was also fol- 
lowed with aircraft leaving Puerto Rico for destinations in the 
southern part of the continental United State-. 
During the }*ear 80,000 airplane.-, carrying 1,600,000 passengers, 
were examined by plant quarantine inspectors. These inspections 
resulted in the interception of :>•',. :.77 lots of unauthorized plants 
and plant product-. Much of this material carried insect pests and 
plant diseases, including such notoriously destructive form- as the 
citrus blackfly, the oriental. Mexican. West Indian, and Mediterran- 
ean fruit Hies, the olive fly. the pink bollworm, a bean pod borer, as 
well as pests of lilacs, grapes, and many other products. 
Destructive Pests Intercepted at Ports of Entry 
More than 109,000 l«>t- of restricted and prohibited plant material 
were intercepted in connection with the Bureau's port inspection 
activities in addition to material taken from airborne traffic These 
inspections are designed to prevent the entry of dangerous insect 
pests and plant diseases by mean- of -hip. train, vehicular, and 
pedestrian traffic Thousands of pests, including insects, plant di<- 
. and nematodes were collected from this huge amount of 
material. Most of the world's most serious agricultural pests were 
among those intercepted. 
A total of L,678 importations of plant material were entered 
through the Hoboken, X. J., inspection house in L951. Of these, 
L,342 l«'t- were fumigated or given some other treatment. 
Destructive pests prevented entry into the country with plant 
material |>;i--iiiL r through the llnl.oken inspection hou-e included 
nearly 500 l<>t- of insects, plant diseases, ami nematodes intercepted 
there. 
An improved system was devised and put into effect for labeling 
plant- being grown under po-tcntry quarantine. This label bear- 
