Bulletin: Volume 2, Issue 20
In the last Bulletin we gave the results of an experiment with the hopperdozer or tar pan on a piece of pasture land in increasing the capacity of pasturage. At the same time we were working upon the life histories of the more destructive species of leaf hoppers, and a summary of those results with their economic bearing will be presented here.
Our first effort was to determine the manner in which the winter is passed. Adults of several of the species studied had been observed late in autumn and early winter and even on mild days late in December, so that it was at one time thought they might hibernate and deposit eggs in spring. Careful search, however, in early spring failed to discover any of them except Agallia sanguineolenta, which, as heretofore shown, is mainly a clover insect, and Tettigonia hieroglyphica, which occurs mostly in wooded places. No specimens whatever of the species of Deltocephalus and Diedrocephala, which are the most destructive pasture species, were found. This seemed to show pretty certainly that the eggs were deposited in autumn, and the question next to determine was where they were laid. To determine this point, as well as to secure additional evidence as to the possibility of adults living over winter, a small patch of blue grass sod was enclosed by a tight board set on edge fitting closely into the ground and extending up about two feet so as to make it impossible for any of the leaf hoppers to enter from without. The enclosed patch was carefully examined to make sure that no hoppers, either young or old were present, and it was examined very frequently as well as the outside portions, to determine just when young hoppers appeared. As soon as the larvae appeared in grass land outside they appeared also in this enclosed patch in large numbers, showing we think conclusively that the eggs are deposited in the grass itself and as other observations have shown that they are placed in the blades of grass, there is apparently no reason to doubt that the eggs occur in the dead or withered leaves of grass near the ground through winter and in early spring.
For the benefit of our readers who are not familiar with the agent Mallein and its uses we will say that it is a preparation obtained by growing in culture media, the bacillus of glanders, and that as yet its only use has been as an aid in the diagnosis of doubtful cases of this disease.
The Mallein used in our experiment was prepared by the Bureau of Animal Industry and kindly sent us by request of Dr. Stalker. In regard to the mode of preparation I quote as follows from an article by Drs. Schweinitz and Kilborn: “Acid peptonized beef broth cultures, containing five per cent glycerine were inoculated with the glanders bacillus and the cultures allowed to grow for two months at the temperature of the room. At this time the growth which had been abundant had almost entirely ceased. The liquid was then heated for two hours from 80 to 100° C., after which it was filtered through a Pasteur tube to remove germs. The resulting clear amber liquid, after being tested to prove the absence of germs and diluted with five per cent glycerine for better perservation was used for injection.”
Co-operative work with farmers in the study of sugar beet culture was continued during the season of 1892.
This work was begun the year previous, in which year the station distributed seed to a large number of farmers, and in autumn analyzed 502 samples of beets, grown in 51 counties of the state. (See Bulletins 15 and 17.)
Last spring (1892) the interest manifested by the farmers was much less. Only fifty-two applied for seed, and in autumn only eighteen of these sent in beets for analysis. Of the remaining thirty-four only three sent any explanation— which was in all three cases “a total failure of the crop.” No doubt the failure of most or all of the others to send in beets was due to a like cause; for not only was the season generally unfavorable, because of the unusually wet and backward spring, but moreover the writer is convinced from his own trials with the seed that much of that which he sent out was deficient in germinating power. This statement is due to those who faithfully tried and failed to get a crop; and on the other hand it is but fair to the writer to state that he procured the seed for that of “the very best quality” from a company which imports and distributes large quantities each year.
Since the admirable experiments of Jensen in Denmark, Dr . J. C. Arthur, of Indiana,1 and Profs. Kellerman and Swingle in Kansas,2 there is no longer any doubt as to the advisability of treating to prevent oats smut and bunt of wheat with hot water. Kellerman and Swingle3 have shown that loose smut of wheat cannot be prevented by treating the seed. They also conducted a series of experiments to determine whether com smut can be prevented by treating the seed. Their results show that the treated contained as much smut as the check. The same year Pammel4 reported an experiment with corn in which the results were also of a negative character. This was in line with results of Brefeld’s5 investigations, but overlooked by the writer at that time. Brefeld’s work indicates that smut of corn can enter any merismatic or growing tissue.