78 BUREAU OP ENTOMOLOGY AND PLANT QUARANTINE [Apr.-June 
6 thereto (sec. 301.64-6), that all grapefruit harvested on and after April 12, 
1939, in the area regulated under said quarantine, shall be sterilized under 
approved methods as a condition of issuance of permits for movement of such 
fruit from the regulated area. 
Section A, regulation 7 (sec. 301.64-7) of said quarantine is also hereby 
modified to extend the harvesting season for grapefruit to the close of May 15, 
1939. The host-free period for grapefruit, under this modification, will begin 
May 16 and continue to August 31, 1939, inclusive. (B. E. P. Q. 487, dated 
Januarv 27, 1939, extends the harvesting season for Valencia oranges to June 
15, 1939.) 
Sterilization of grapefruit has been found necessary to insure against dis- 
semination of Mexican fruitflies, due to the occurrence of such flies in the 
regulated area. The extension of the harvesting season, it has been determined, 
may be safely made without increasing the risk of spread of the Mexican fruit- 
flies siuce sterilization will render grapefruit safe for movement from the 
regulated area. (Sec. 301.64b, issued under authority contained in sec. 301.64.) 
Lee A. Strong, 
Chief, Bureau of Entomology and Plant Quarantine. 
ANNOUNCEMENTS RELATING TO WHITE-FRINGED BEETLE 
QUARANTINE (NO. 72) 
B. E. P. Q. 496. 
SUGGESTIONS FOR CONSTRUCTION OF PLUNGING AND GROWING BEDS AND THEIR 
MAINTENANCE UNDER BEETLE-FREE CONDITIONS IN ACCORDANCE WITH REGU- 
LATIONS OF THE WHITE-FRINGED BEETLE QUARANTINE 
April 28, 1939. 
Nursery stock with soil attached is eligible for certification for movement 
from areas under quarantine on account of the white-fringed beetle provided 
it has been grown and maintained under beetle-free conditions, as specified in 
paragraph (&) of regulation 5 of Quarantine No. 72. 
The following types of units are suggested as means of providing for beetle- 
free conditions and if properly maintained should be effective in preventing 
natural infestation by the white-fringed beetle. 
RAISED PLUNGING BEDS 
Beds or benches, indoors or outside, which are at least 12, preferably 18 
inches, above the ground, and which are protected from infestation in manner 
and by method satisfactory to an authorized inspector. Structures * * * 
are to be protected against infestation by approved oil or other barriers. 
SURFACE PLUNGING OR GROWING BEDS 
A heeling-in area or growing grounds enclosed within walls extending far 
enough underground to prevent larvae from passing under. This may require 
a wall as much as 24 inches in depth. The walls should be of sufficient height 
above ground to permit the construction of oil or other barriers on a level 12, 
preferably 18, inches above the ground. The soil or other material contained 
or used therein should be treated in approved manner under the supervision 
and direction of an authorized inspector. Such articles not immediately placed 
in the units should be adequately protected from infestation. 
During the active adult beetle season, barriers constructed in connection with 
plunging and growing beds should be properly maintained, and adequate sani- 
tary and protective measures should be taken by establishments concerned to 
fully protect the approved units from infestation. Vegetation should be kept 
down and calcium arsenate dust or other specified treatment applied to the 
satisfaction of an authorized inspector. 
BARRIERS 
It will be necessary to protect the beds during the season of adult activity 
by approved barrier. 
Whenever practicable, the oil barrier is recommended. The heavy construc- 
tion enables it to withstand jars or jolts which would greatly decrease the 
efficiency of the all-metal barrier. 
