BACTEKIAL WILT OF CUCURBITS. 17 
Experiments of 1917. — In August, September, and October, 1917, 
at Tuxedo, Md., about 5,000 of these two species of cucumber beetles 
were collected. Special care was taken not to injure the beetles in 
any way, and they were placed at once in the cages (PL II, fig. 1) 
standing in the fields where they were caught. Three species of 
cucurbits were growing in these cages and also corn in a few of them. 
Some of the cucurbits were inoculated with the wilt organism and 
others were left uninoculated. After the growing plants in the cages 
had died, squashes and other cucurbit fruits were fed to the beetles 
until November, 1917. A few of these cages were destroyed by 
winds during the succeeding winter, but in the 13 remaining intact 
not a single beetle appeared in the spring of 1918. It might be 
added, however, that in one of these cages into which several squash 
lady bird (EpilacTina borealis) had been introduced the preceding 
fall, three live individuals were found in May, 1918. 
These attempts at hibernation of wilt-fed cucumber beetles under 
experimental conditions have been rather discouraging, since, so 
far as ascertained, none have lived longer than six weeks under the 
hibernation conditions used. 
On the other hand, striped cucumber beetles collected at the same 
time and place for the direct wilt-transmission experiments in the 
warm air of the greenhouse have frequently been kept alive and 
active in small cages (PI. I) for three to five months, and in two cases 
for more than six months (Oct. 4, 1916, to Apr. 28, 1917). These 
beetles were fed upon potted young cucumber plants which were 
frequently changed, and they were under almost daily observation. 
DO THE WILT BACTERIA WINTER OVER IN THE SOIL? 
Experimental carrying of the wilt organism through the entire 
winter by the beetles has failed, on account of our inability to keep 
the beetles alive for that length of time under the hibernation con- 
ditions given. However, the problem has been attacked from other 
angles and some further evidence has been accumulated to show 
that the striped cucumber beetle may be a winter carrier of Bacillus 
tracheipMlus. 
In eastern Long Island the previously reported * cage experi- 
ments were repeated during the summer of 1916. In the original 
experiments (1915) 50 large, wire-covered cages (PL II, iig. 2) were 
set in two fields where during the preceding season about 75 per 
cent of the cucumber plants had been infected with wilt. In Sep- 
tember, 1915, and again in May, 1916, the soil in one-half of these 
cages was heavily inoculated with well-water suspensions of tested 
virulent wilt bacteria. No beetles were introduced, and not a single 
i Rand, F. V., 1915. Op. cit. 
142179°— 20— Bull. 828 3 
