BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 43 
cultural Experiment Stations, the Bureau of Plant Industry, Soils, 
and Agricultural Engineering, and the Bureau of Entomology and 
Plant Quarantine. The Bureau's contribution to the work was 
financed with funds made available through the Research and 
Marketing Act. 
Two Species of Aphids Determined as Vectors of Strawberry Virus 
Diseases 
Many specimens of aphids suspected of being vectors of certain 
virus diseases of strawberries have been submitted for identification 
from widely separated strawberry-growing areas of the United States. 
These virus diseases, that result in a yellowing or stunting of the 
plants, are under investigation by the Bureau of Plant Industry, 
Soils, and Agricultural Engineering and several State agricultural 
experiment stations. Originally only one aphid species was thought 
to be responsible. Recent studies by the Bureau's taxonomists have 
established the involvement of two distinct species of the genus 
Capitophotms. one of them still undescribed. Both species are found 
on the west coast and in Wisconsin. Only the undescribed form has 
been represented in collections from strawberries in the Eastern 
States. 
Materials for Controlling Most Pecan Insects Now Available 
Pecan growers can reduce infestations of the pecan nut casebearer 
with suitable insecticides applied at various times during the season, 
according to the results of recent tests. DDT, which has become the 
most commonly recommended insecticide for this insect, continued to 
give good results both in experimental plots and in applications made 
by pecan growers. Tests in Florida and Texas indicate that more 
latitude in the timing of sprays may be permissible when DDT is used 
than with the older treatments. 
In Florida five summer applications of DDT or parathion at 3-week 
intervals, the last on September 11, eliminated overwintering nut 
casebearers in all but one plot, which was sprayed with parathion 
and showed -a high reduction. Single spray applications of DDT or 
parathion late in the dormant period reduced twig infestations caused 
by overwintered larvae. In tests of single, well-timed applications 
for control of first-generation larvae, DDT, parathion, lindane, and 
ethyl ^-nitrophenyl thiobenzene phosphonate (EPN), each in com- 
bination with oil and bordeaux mixture, were either equal or superior 
in effectiveness to nicotine sulfate with oil. DDT in bordeaux mix- 
ture without oil also was outstanding. Mist-blower spray applications 
of parathion, in combination with oil and ziram, indicated that this 
method has definite possibilities for control of the nut casebearer. 
In Texas one or two applications of DDT, toxaphene, parathion, 
and EPN for control of first-generation larvae gave high yields of 
nuts, despite a heavy initial infestation. The best yields were ob- 
tained in plots that received two applications of DDT with summer 
oil or two applications of parathion. 
Some progress has been made in developing spray programs for the 
simultaneous control of all the major insects and diseases that attack 
pecan trees. Effective materials for controlling most of the insect 
