100 ANMWI. RKI*(»RT> 01 DKTARTM KXT OF AGRICULTURE, 1940 
of the parasite it' they are in the pupal stage. Advantage can be 
taken of this resistance <»t' the parasites in timing field fumigation. 
The coccinellid beetle Lhu/orU8 lophantcu (Blaisd.) i- very suscep- 
tible to cyanide fumigation, whereas t 'ryptouu m us montrou&u ri Muls. 
shows a low mortality at standard dosages. Tartar emetic -prays 
were found to be very injurious to adults of the para>ite Com />rro/la 
bifasciatdi while amon<r the predaceous beetles it was distinctly 
harmful to Lindorus lophantae and Coccidophitus citricola Brethes, 
whereas C ryptohi, unis is little affected by it. apparently because the 
beetles do not feed to any extent upon the spray deposit. 
In the investigations of fundus disease- of xale in>ects. particu- 
larly the purple scale, in Florida, new methods were devised for 
sampling the population to determine the incidence of disease under 
different treatments and the effect of the disease on the host at differ- 
ent population levels. Final results established that the disease has 
little or no effect upon the scale population, that the scale build-up 
after spraying is due to a granular residue left upon the foliage after 
spraying rather than to destruction of the Fungus, and thai fungicidal 
spray- can be applied against citrus diseases without a resultant 
build-up of scale- provided the material used does not leave a granular 
residue. 
COOPERATIVE WORK WITH PUERTO RICO 
Cooperation with the Puerto Rico Agricultural Experiment Station 
of the Office of Experiment Stations in the importation of natural 
enemies of crop pests has been continued and has been extended to the 
Experiment Station of the University of Puerto Rico. This Division 
has supplied directly, or lias arranged through Stale agencies for the 
importation of ryptochaetum iceryae (Will.) for colonization against 
the cottony cushion scale and of four specie- of parasites of the black 
scale. Shipments from Puerto Rico to the United States comprised 
an additional stock of the Sao Paulo strain of the Amazon lly parasite 
of the sugarcane borer and a colony of Coelophora inaequalis (F.), 
a predator upon the sugarcane aphid. 
COOPERATION WITH FOREIGN ORGANIZATIONS 
In addition to the cooperative work upon spruce sawfly parasites 
with the Canadian Department of Agriculture, which has already 
been mentioned, this Division has arranged for the shipment of a 
colony of (rinnhi o* xtokcsii Cam. to that organization for use against 
the codling moth and for a shipment of the oriental fruit moth para- 
site M acrocentrics ancylivorUS to Japan. The staff of the Yokohama 
station cooperated with a representative of the Rehavoth, Palestine, 
Agricultural Research Station in locating natural enemies of Pseu- 
dococcus ootnstcchi and in preparing colonies for shipment to Pales- 
tine. Assistance was also given in the forwarding of large-scale ship- 
ments of oriental fruit moth parasites from the United State- to the 
Australian Council for Scientific and [ndustrial Research. 
Through the courtesy of the Egyptian Mini-try of Agriculture a 
further shipment of 600 cocoon- of M icrobracoti kirkpatricki. an 
African parasite of the pink bollworm <>f cotton, was secured to 
provide a new stock for rearing purposes. 
