6 BULLETIN 1357, U. S. DEPARTMENT OF AGRICULTURE 
During the winter of 1919-20 Primm and Trimble, of the Pennsyl- 
vania Bureau of Plant Industry, found infestations in 15 different 
establishments in the vicinity of Philadelphia. According to two 
florists in this locality, the beetles, known to them as “ chocolate 
bugs,” had been encountered in their houses for 12 and 18 years, 
respectively. 
A careful survey by means of a circular letter sent to all the State 
entomologists and the subsequent publicity accorded this insect and 
its injury in florists’ trade journals (7, 17, 19, and 24) have brought 
to attention infestations in the States of Michigan, Missouri, Lou- 
isiana, Rhode Island, and Massachusetts. These reports emphasize 
the fact that the insect is now of prime importance in practically 
all of the commercial rose districts of the United States east of the 
Rocky Mountains. The severity of injury found in houses or beds 
where the plants were 3 or more years old indicated that they were 
the sources of infestation, and that the insect had been brought in 
either with the soil or the plants in those sections. 
DISTRIBUTION 
The strawberry leaf beetle, or adult of the rootworm, which is a 
native insect, has been frequently recorded as occurring out of doors 
generally throughout the United States and Canada (Z4, p. 25). 
The records available at the present time show that it 1s injurious 
to roses under glass in the District of Columbia, Illinois, Indiana, 
Louisiana, Maryland, Massachusetts, Michigan, Missouri, New Jer- 
sey, Pennsylvania, Rhode Island, and Virginia. 
NATURE OF INJURY AND ECONOMIC IMPORTANCE 
Two stages of the strawberry rootworm are involved in the injury 
to the plants, (1) the adult and (2) the larva. The casual observer 
immediately notices the ravages of the beetles on almost every part 
of the plant above ground. The leaves become perforated so exten- 
sively that one easily imagines charges of small shot being fired at 
the plants. This shot-hole appearance (fig. 1) is very characteristic 
and completely destroys the ornamental value of the foliage. The 
beetles also eat the green succulent bark of the forced plants, par- 
ticularly in crotches, scarring and often girdling the stems. 
The most serious injury to the plants occurs when the tops are 
“cut back,” because little foliage remains for the beetle to feed upon. 
At this time the beetles severely scar the stems and eat into the 
“ eyes,” as the developing buds are termed by the florists. The im- 
portance of this particular type of injury is very evident when it is 
considered that the future crop of flowers depends on these buds, 
which require from six to eight weeks to develop, and that any set- 
back naturally results in a decreased production and financial re- 
turn. The succulent nature of this growth, as compared with the 
woody stems, causes the beetles to center their attention upon it, and 
in a single night they may eat the heart out of almost every eye. 
In one infestation observed in March, after the buds of Ophelia 
plants had been destroyed during September and October of the 
previous year, the first growth produced from these nodes was only 
