Deterioration Sugar Beets Due to Nitrates 137 
attack looked very badly indeed. One of our plots which had suf¬ 
fered to this extent i. e. the loss of from 25 to 43 leaves per beet in 
the latter part of July and early August (25 July to 15 August) 
yielded 16.85 tons of beets per acre with 16.85 percent sugar. The 
average yield of beets in the vicinity of Fort Collins in 1910 was 
less than eleven tons per acre and the average percentage of sugar 
was about 15.5 percent. By reference to the record of the 120 leaf- 
spot fields given in the earlier part of this bulletin, it may be seen 
that their aveiage yield was 12.4 tons beets per acre and the average 
sugar content was 13.9 percent. There was no leaf-spot in the Fort 
Collins district, but it was very prevalent in these 120 fields. The 
distance between the remotest of the leaf-spot fields from one an¬ 
other is not far from 150 miles, while that between the Fort Collins 
district and the nearest of the leaf-spot fields is about 200 miles. Still 
consideration must be given to the question of locality. The big 
fact, however, remains that the yield of these leaf-spot fields if fully 
an average one and that we cannot detect any relation between the 
virulence of the attack and the yield or the percentage of sugar. 
The time of attack, beginning about 25 July, would lead us to expect 
very pronounced and disastrous results. I believe that in some in¬ 
dividual cases that very disastrous results may follow the attack, but 
it seems very doubtful whether the effect of this disease is generally 
so great as we have thought, especially upon the yield of beets and 
the percentage of sugar, but there are other ways that the destruction 
of the foliage may affect the beets. Some of these have been given 
in the preceding quotations from Andrlik and Urban, also from 
Strohmer, Briem and Fallada. I have undertaken to study some 
further features of the effects of defoliating the beets in two experi¬ 
ments, just as I have endeavored to study the effects of the nitrates 
to see whether the effects of defoliation are the same as those of the 
nitrates. 
For this purpose I selected five rows of each of the two varieties 
expei imented with and defoliated them on 6 Sept. The beets were 
growing rapidly at this time. The tops were removed by means of 
a knife, we left no leaves which had fully expanded, only the small 
undeveloped ones at the center of the beet. The beets put out per- 
haps 50 percent of a full foliage before they were checked by the 
freezing of the tops, which happened 20 Oct. The weather had 
been fine up to this date. The beets were harvested 8 Nov., almost 
exactly two months after defoliation. Samples of these beets were 
taken 1 Sept., when the results were as follows: average weight of 
beets, E R 625.3 grams, average weight of tops 735.6 grams, Z R 
average weight of beets 510.3 grams, of the tops 614.3 grams. The 
percentage of sugar in E R was 11.9 and in Z R 13.2. At the time 
of harvest the check plots gave for E R average weight of beets 
