G ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 194 4 
PROGRESS MADE TOWARD ERADICATION OF HALL SCALE 
Marked progress is beinp: made toward the eradication of the Hall 
scale from the area around Chico, Calif. Inspections have been made 
at several localities to which shipments from the United States Plant 
Introduction Garden were sent before fumigation was adopted, but 
no new infestations have been found. Further surveys of this kind 
art' beinir made. 
Spraying with oil, although not giving perfect kill, has reduced 
the infestation to a low point, thus minimising the danger of spread. 
Test fumigations with hydrocyanic acid <ras under tents have given 
complete kill of all scales present, and final eradication by means 
of fumigation seems entirely feasible. 
FRUITFLY INVESTIGATIONS 
In Mexico preliminary studies with DDT in dusts and oil prepara- 
tions have shown promise in preventing fruit infestation. 
In Mexico also sublethal quantities of tartar emetic ingested by the 
Mexican fruit fly were shown to inhibit egg development. 
Infestation tests in Hawaii on tomato varieties developed by the 
agricultural experiment station there have shown three hybrids that 
are highly resistant to the melon fly. 
At the Canal Zone station studies in addition to those on fruitflies 
are under way to determine the resistance to termites of different 
cable-insulating materials. 
INVESTIGATIONS OF INSECTS AFFECTING FOREST AND SHADE TREES 
ENGELMANN SPRUCE BEETLE OUTBREAK IN COLORADO 
An extensive outbreak of the Engelmahn spruce beetle has developed 
in Colorado during the last 2 years. The infest at ion was iir>t reported 
on the White River National Forest in 1942, and it is now known to 
be present on the Grand Mesa, Routt, Uncompahgre, and Gunnison 
National Forests. An estimated 150 million board feet of Engelmann 
spruce has been killed on the White River and the Grand Mesa Na- 
tional Forests. The Forest Service is attempting to salvage as much 
of this dead timber as possible. About half of the timber resources 
of Colorado and Wyoming, or approximately 20 billion board Ceetj 
consists of Engelmann spruce. Much of this timber is mature or over- 
mature, and conditions are apparently favorable for continued wide- 
spread destruction by this beetle. On one small area on the White 
River National Forest where a recent survey was made, it was found 
thai 35 million board feet, or 77.5 percent of the stand, on 2,227 acres, 
had been killed since February L942. Since very little is known about 
this Insect, it is impossible to make recommendai ions for control at the 
present time. A study is to be made oi its life history as a basis for 
control work, [nfested trees are difficult to detect because the foliage 
does not change color as does that of pines Infested with bark beetles. 
PINE BARK BEETLE SITUATION CONTINUES FAVORABLE 
Bark beetles that attack the various species of Western pint's caused 
comparatively little damage during the past year. There were a few 
