REPORT OF EXPERIMENTS AT AMES, IOWA. 
By Pror. HERBERT OSBORN. 
Sir: I send you with this a summary of my tests of various reme- 
dies for cabbage insects, &c. My work has been almost entirely con- 
fined to cabbage pests, as some of the insects mentioned in your in- 
structions had already passed the active stages, while some mentioned 
have not appeared in this locality. There are no gardens worthy the 
name in the vicinity, so that some of the most common vegetables, with 
the insects infesting them, have not been within my reach. Even 
cabbages were rather scarce this year. One patch of about eighty plants, 
on the college farm, was quite well stocked with insects—Pieris rape, 
Plusia brassice, Plutella cruciferarum, Aphis brassice, Haltica striolata, 
&e. Another patch on the college farm, containing a greater number of 
plants, contained scarcely one with a solid head, and they were so poor 
that the insects seemed to consider them beneath notice. Secarcely a cab- 
bage worm could be found there during the entire fall. 
A small patch of about eighty plants, on a farm owned by Professor 
Mount, was quite free from worms till the 1st of October, after which 
they were more plentiful, and served for experiments with several sub- 
stances. The small number of plants necessitated experimenting on a 
few for any one substance, and going over the same plants with other 
remedies after the iapse of a few days, sufficient to note results. 
The appearance of the epidemic disease among the cabbage worms, 
mentioned in connection with the cold-water experiments, made it 
necessary to be very careful in judging of results. It commenced 
about the middle of September, and continued till all the worms disap- 
peared, great numbers dying from it, though all the plants in a patch 
would not be found to contain diseased worms at the same time (at one 
time a great many dead or diseased worms could be found at one end of 
the patch and none at the other). The characteristic appearance of the 
worms dying of this disease makes it easy to distinguish them for a time 
after death, but Jater they turn dark and shrivel,and do not differ much 
from worms that have been killed by parasites or predaceous insects or 
by application of remedies. Parasites have been quite abundant, both 
in Aphides and worms. Coccinella larve and adults, Syrphus larve, 
and Ichneumons were on hand, and I noticed one cabbage worm im- 
