————— — 
-—- 17 = 

peratures for wireworms.--E. W. Jones. Wall 
CS, 
et 
2 7 
ports that "In connection with investigations on low femperaiire ag 
a factor in the ecology of wireworms, a study of winter soil tempera- 
tures and their relation to soil insect survival was completed this 
month (March). Three field conditions were studied. * * * alfalfa- 
covered ground with snow; bare ground with snow cover; and bare ground 
without snow cover. * * * The soil temperatures in the alfalfa—cov-— 
ered field with snow were the highest and most constant of all these 
fields. Temperatures in the alfalfa never went below 32° F. The field 
of bare ground with snow cover was intermediate between the alfalfa 
field and bare ground without snow. The temperatures of this field 
never went below 30.2° F., however. The extreme low soil temperatures 
occurred on bare ground without snow. * * * Under normal conditions 
soil temperatures do not get low enough to kill hibernating wireworms. 
The hibernation depths for the majority of the worms are from 6 to 
iz inches. Soil temperatures of bare ground are not likely to go below 
50.2° F. at 6 inches. Such temperatures would hardly affect wire- 
worms which have average undercooling points and freezing points of 
15.8° F. and 19.4° F., respectively." 
seed-corn maggot in potatoes.—-W. J. Reid, jr., Charleston, S. C., 
reports that "During March," he "kept under close observation the two 
potato demonstration plots planted in Charleston County in cooperation 
with local growers and the County Agricultural Agent. * * * The soil 
during the winter has been too dry for organic matter to decompose so 
that it would prove suitable as food for the seed-corn maggot. Conse- 
quently there has been a very small population of the seed-—corn maggot, 
in the soil this spring and littie injury to potatoes." The infestation 
of seed freshly cut when planted was 12 per cent, while in seed swber— 
ized in advance of planting it was zero. 
FOREST INSECTS 
T. Webber, of the gipsy moth laboratory, Melrose Hhighlands, Mass., has 
continued his studies of these species and states that the "results of 
this study confirm tentative statements made in previous reports to the 
effect that the species are distinct and can be identified as such in 
at least two stages of their life." 
"Wilt" important factor in sipsy moth control.--R. ©. Brown, Mel- 
rose Highlands, submits the following report on "wilt": "Observations 
have been made on this important polyhedral disease of Porthetria dis-— 
par L. larvae and pupae since the ‘observation point' project was started 
in 1912. From 1915 to date collections of larvae have been made each 
year at points which represent fairly well the older infested area and 
An accurate record of those larvae which have died of the ‘wilt' -dis- 
ease has been kept. An examination of these records shows that there 
were two years when the mortality caused by ‘wilt' was distinctly high- 
er than in other years throughout this period. In 1920 a mortality 
wu 
