(J2 ANNUAL REPORTS 01 DEPARTMENT] 01 AGRICULTURE, L951 
lean foul brood in different strains of brood of identical age reared at 
the same time by the same nurse bees in a heavily diseased colony 
appears to be evidence thai the resistance <>l some strains is at leas! 
part ially physiological. 
I Itraviolel Li^Iii \i<U Disease Detection 
In many samples of diseased brood comb submitted for laboratory 
diagnosis it is difficult to locate the brood remains. A simple and 
rapid method of locating such material has been devised. It is based 
en iIm' fact that dried larval remains-emit a green fluorescence when 
sxposed i" ultraviolet light, whereas the comb does not. The contrast 
I etween the brood remains and the comb is striking, revealing imme- 
diately the presence and location <d' even minute brood remains. 
INSECT IDENTIFICATION 
The Bureau provided prompt insect-identification service for fann- 
er-, householders, and public and private agencies. Accurate identi- 
fication is the first Step in any attempt to control any insect pest. 
More than 60,000 -ample- of insects were identified during the year. 
In support of insect identification, and particularly to assure the 
most accurate and precise identifications possible, research in classifi- 
cation of many insect groups is constantly in progress. Emphasis 
has been placed on taxonomic studies of spider mites because there 
is some confusion as to what this group include- and because of the 
importance of precise identification of forms differing in resistance 
to certain mit icides. 
NEMATODES INFESTING POTATOES 
Control of Golden Nematode Continued 
Golden nematode of potatoes still confined /<> Long Island 
Laboratory processing of soil -ample- collected in all principal 
potato-growing area- of the United States failed t<» disclose any 
infestations <>t' t he L r< >lden nematode ot her than t ho.-e on Long I -land. 
[ntensive surveys on Long [sland showed infestation on 29 addi- 
tional farms, 20 in Nassau County and i» in Suffolk County, The 
most significant find was in a -mall potato held near Bridgehampton 
on the -onih fork of eastern Suffolk County. This isolated find is 
approximately 60 miles from the nearest previously known infestation. 
At the end of June 1951, infestations had heen confirmed on 9,800 
acres. A.bout 3,600 of these acre- have been permanently removed 
from cultivation because of real estate developments. 
[nfestations war found <>n four properties during a survey of 
nurseries and retail establishments in Kim:-. Nassau, Queens, and 
Su iloiu ( oiini ies, on I <ong [sland. 
Surveys were made in cooperation with 39 States. Nearlj 136,800 
lot of joil samples, representing soil from 505,000 acre- on which 
white | otatoes were planted, were collected at potato grading, stor- 
age, and shipping points and in potato and loiuato fields. Sample- 
