BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 29 
Field experiments with oil-cube and DDT sprays in Sonora, Mexico, 
greatly reduced blackfly populations in the vicinity of Empalme. 
Similar experiments in the Valles area in eastern Mexico indicate that 
the pest can be controlled in commercial groves with two spray appli- 
cations a year. It was found that oil-cube sprays, although highly 
effective against larvae and pupae on the leaves, do not prevent eggs 
from hatching, but few of the larvae that emerge are able to mature. 
In experiments with insecticide treatments of limes before shipment 
to the United States, pyrethrum mixtures showed the most promise. 
This work was conducted with funds authorized under the Research 
and Marketing Act. 
One small air shipment of parasite material from Malaya was re- 
ceived at Colima, Mexico, during the year, and ProspalteUa spp. was 
released in citrus groves. The search in Cuba for the effective preda- 
tor, Catana clauseni Chapin, was unsuccessful. 
Many citrus groves and most of the dooryard plantings in towns 
along the Mexican border were inspected during the year, but no 
infestations of the citrus blackfly were found. 
Treatments to Kill Fruit Flies Permit Movement Under Quarantine 
The Mexican fruit fly infestation in the regulated area of Texas was 
near normal during the early part of the harvesting season of 1948-49. 
Flies were beginning to appear and some larvae were found before 
January 29, when a hard freeze severely damaged the trees and much 
of the fruit. This abnormally cold weather apparently caused some 
delay in egg laying. As a result most of the fruit crop undamaged by 
the freeze was moved before the infestation built up to a point that 
required general sterilization. The new market that has opened up 
since Arizona and California have permitted the entry of citrus from 
Texas under Federal certification is expected to develop into an im- 
portant outlet for high-quality grapefruit and oranges. Over 500 
cars of citrus fruit were shipped from Texas to California this season 
under Mexican fruit fly certification. 
The Bureau again assisted Argentine authorities in the develop- 
ment of equipment and facilities for the shipside precooling of fruit 
and for in-transit sterilization to kill larvae of the Mediterranean 
fruit fly. More than 300,000 boxes of deciduous fruit were thus treated 
during the 1948-49 season as a requirement for entry into the United 
States. 
New Laboratory for Study of European Chafer 
A study of the European chafer (Amphimallon majalis (Razoum.) ) , 
a foreign pest which feeds in the grub stage on the roots of field crops, 
grasses, and other plants, was begun in the spring of 1949. This insect 
was first recognized as a pest new to this country in 1942. It occurs in 
a limited area near Newark, N. Y. Since this insect might become 
a serious economic pest if it should become widely distributed in the 
United States, the New York Agricultural Experiment Stations re- 
cently requested this Bureau to participate in a cooperative investiga- 
tion of the problem. Headquarters for the work are with the New 
York Agricultural Experiment Station at Geneva. 
