STRAWBERRY ROOTWORM ON GREENHOUSE ROSES 39 
_under observation succumbed shortly thereafter, thus corroborating 
the earlier results. Other extensive tests were tried on a total of 
» about 20,000 bushes with the same degree of effectiveness. 
| This treatment therefore finds convenient application, especially 
_ when the new growth has started after the resting period, and in the 
. fall when it would be inadvisable to employ other remedies, such as 
| fumigation or spraying. Furthermore, every adult killed then would 
_ mean so many less the following spring. 
SCRAPING THE SOIL OF BEDS 
| It is a cultural practice among rose growers to scrape off 1 or 2 
| inches of the loose, dry surface soil from the beds during the drying- 
| off period immediately after the plants have been cut back. The soil 
| is then thoroughly soaked with water, bone meal is applied as a fer- 
' tilizer, and a mixture of well-rotted manure and composted soil is 
| used to replace the removed layer. Certain modifications of this 
| method, such as making deep furrows between crossrows of plants 
_ and filling them with manure, are also used. 
| Examination of the material removed from infested beds disclosed 
, 30 adults in the soil surrounding 6 plants, and in another place 14 
| were found near 3 plants. Their prevalence at this time suggests a 
| practical means of destroying many beetles by shaking the plants 
» and by removing the soil from the house and treating it as soon as 
| the plants have been cut back. Unless this is done at once, however, 
| the beeties will severely injure the plants by devouring the buds and 
| girdling the stems. 
CLEAN CULTURE 
In a certain establishment already discussed under hand picking 
it was customary to keep the beds immaculately clean and to apply 
liquid manure instead of a mulch to the soil. At all times the beds 
were kept free from dead leaves and débris by the workmen, who 
removed them at frequent intervals and burned them. These beds 
had the appearance of having been swept with a broom. Undoubt- 
edly this practice contributed much toward reducing the infestation, 
not only by removing many beetles and preventing the remainder 
from hiding in the dead leaves over winter but also by decreasing 
proportionately the amount of egg deposition in the spring. More- 
over, it prevented many newly hatched larve from reaching the soil. 
From February until September the leaves should be removed every 
10 days in order to destroy the eggs in them... In heavy infestations 
it is desirable to fertilize the beds with liquid manure instead of 
mulching. 
SOIL TREATMENT 
Since the larva and pupa stages, requiring about six to eight weeks 
for their development, are spent in the soil, they appeared to furnish — 
a period when the insects would be susceptible to control by means of 
soul treatments. During the first season efforts were therefore di- 
rected primarily toward finding some soil application, either an 
insecticide or a fertilizer, which would operate against these stages 
and hence prevent the emergence of the adults. With this object in 
