BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 25 
Eradication of the poach mosaic disease is necessary from a commercial 
standpoint. The results of the year's work in the infected area in Colorado 
have proved conclusively that an eradication program is practicable. 
Peach mosaic disease has recently been found in California, New Mexico. 
and Utah, and during 1937 survey and eradication activities will be extended 
to those States and to Arizona and will be continued in Colorado and Texas 
to the extent possible under a $25,000 allotment from the Emergency Relief 
Appropriation Act of 1936. 
CITRUS CANKER ERADICATION 
Federal and State activities directed toward the eradication of citrus canker 
have been in progress for over 20 years. Eradication of this disease was 
apparently accomplished prior to 1928 in all the Gulf coast area except a non- 
commercial district in Texas and Louisiana ; most of the work incident to this 
undertaking has. therefore, long since been completed. However, the very 
difficult task of destroying the last vestige of this disease in the United States, 
which marks the vast difference between eradication and effective control, still 
remains to be accomplished. 
The area now known to be infected is that in which Satsuma orange produc- 
tion was undertaken on an extensive scale 20 to 25 years ago. but in which, owing 
to the ravages of citrus canker and to severe winter-kill, the enterprise was 
abandoned as a commercial industry. However, the cold-resistant Citrus tri- 
foliata root stock has not only survived but has become naturalized, and infected 
plants are now being found intermingled with other vegetation long distances 
from original plantings. Eradication is, therefore, very difficult and necessitates 
thorough, intensive, and systematic inspection under adverse conditions. 
Citrus canker inspection was placed on an intensive basis about the first of 
the year 1935. and in a period of 6 months the disease was located on 31 proper- 
ties in the Galveston-Houston district of Texas. In the fiscal year 1936, under 
the campaign of inspection and eradication, the number of infected properties 
found in the district was reduced to six. Inspection in outlying counties brought 
to light an infection center of some years' duration at Beaumont and a few cases 
in Harris County. Recently, under an expanded program, inspection was 
extended to a number of southerly counties, with special attention to properties 
on which the disease was found in earlier years. No canker, however, has been 
located south of Brazoria County in this recent inspection. During this 18 
months' campaign 23 counties have been worked, 4 of which showed canker- 
infected properties. All infected properties have been reinspected again and 
again for any sign of recurring infection. 
In southern Louisiana all the area from the Mississippi River west for 
approximately 100 miles was inspected during the year for citrus canker. The 
remaining citrus area, west to the Texas border at Orange, is now being worked 
intensively, as is the case with respect to an important area east of the Missis- 
sippi along the north shore of Lake Pontchartrain. Eight infected properties 
were found during the year in the parishes of Terrebonne, St. Charles. Lafourche. 
and Calcasieu. 
The problem of surveying the citrus growth in the marsh areas of Louisiana 
was recently solved by the use of an autogiro. Moats on which citrus exists were 
located and mapped on air-photo compilations supplied by the Coast and Geodetic 
Survey. This method of systematically flying over the areas made possible the 
discovery of 24 heretofore unknown locations of citrus growth and proved an 
ideal way to survey the swamp areas. Ground inspection of these trees is now 
under way. 
Under an allotment from the Emergency Relief Appropriation Act of 1935. 
more than 8,000,000 abandoned and escaped citrus trees were destroyed by relief 
labor in Texas and Louisiana. Of these trees. 1.613 were infected by the citrus 
canker disease. The work provided 378,171 man-hours of employment during 
the year. 
DATE SCALE ERADICATION 
A final inspection was given the plantings in the date-growing districts not 
previously dropped as free from parlatoria date scale. Prior to this the pruning 
necessary to facilitate Inspection had been done. Inspection of leaf bases, 
accomplished by peeling the trunks, permitted careful examination of palms on 
