40 BULLETIN 1426, U. S. DEPARTMENT OF AGRICULTURE 
2. A strip in a badly infested clover field in its second crop year 
was plowed 8 inches deep and disked six times on August 28, 1917. 
Borers in all stages were present, approximately 20 per cent of them 
being new, soft adults; only one fully hardened adult was seen. 
The ground was very dry and hard, and plowed in large clods ~ 
very difficult to work up. Flight screens were erected to determine 
if the borers flew from the plot. On September 5 all the borers, 
even adults near the outside of the roots, were dead in the dry, hard 
roots lying on the surface of the ground, or covered by an inch or 
less of dry soil; some exit holes, however, indicated the escape of a 
few root borers. Deeply buried roots were still moist, and contained 
living root borers in larval, pupal, and adult stages. On September 
15 a count on several roots collected from the surface and beneath 
it to a depth of 2 inches showed 70 per cent dead. Living larve, 
pup, and adults were usually on roots which were partly rotten, 
soft, and punky. On November 8, living adults were found on two 
roots buried 4 to 5 inches deep. Some time between September 15 
and November 8 screens caught two borers flying from this plot. 
The maximum temperature during the first 10 days following the 
plowing of this plot was 86° F. Precipitation began on September 6. 
3. A small field seeded in May, 1916, was plowed and harrowed 
with a spring-tooth harrow on August 2,1918. The ground was very 
dry and hard and worked up many hard clods. The spring-tooth 
harrow worked fairly well in raking the roots to the surface, with the 
exception of those deeply buried. The cultivation was as good as 
the average farmer could accomplish at this season. Ten roots were 
found to contain 70.5 per cent of larve, 20.8 per cent of pup, and 
8.7 per cent of adults, there being in all 149 borers. 
On August 10, 50 per cent of the borers in 10 roots gathered from 
the surface were still alive. The roots were dry and hard on the 
outside, but the interiors usually were not yet hard. The weather 
had been cloudy, with light precipitation since the plowing. 
On August 20, 10 roots collected from the surface contained 47 
dead larve, 12 dead adults, and 1 living larva, or 98.3 per cent of all 
were dead. Since the last examination the temperature had reached 
90° F. on one day. 
On October 7 several buried roots were examined, most of them 
being dried up, with no living borers. Live adults were found on 
two roots which were badly decayed, and therefore soft. 
On March 29,1919, a few adults were swept from this plot, more 
than three weeks before the time of their normal flight; many were 
coated with mud from the hard treatment they had received. On 
July 23, a dead adult was found in a groove eaten into a wheat 
stem. Evidently the insect had been driven to abnormal activity 
by the plowing of the clover. 
Webster (46) performed a similar experiment at Wooster, Ohio, in 
1899. In this case the plot was plowed on July 8, about nine days 
before the first occurrence of pup in the field. On August 10, living. 
larvee and pupz were found on roots buried from 3 to 5 inches below 
the surface. On October 19, a rather thorough examination of the 
plot resulted in the finding of only four living beetles on buried 
clover roots. 
