302 
Journal of Agricultural Research 
Vol. XXVIII, No. 4 
The question might be raised as to the possibility of other factors, such as 
variation in rainfall, having entered in to cause the great differences in yield. 
In answer to this question it may be said that irrigation is practiced in all the 
districts and that the amount of rainfall is therefore probably of no great sig¬ 
nificance. The rainfall is given, however, for a representative locality in the re¬ 
gion of each of the districts A, B, and C to show the amount and distribution 
of the rainfall in the seasons of 1917, 1918, and 1919 (Table II). 
Table II .—Rainfall in the region of districts A , B, and (7, seasons of 1917 , 1918 y 
and 1919 
Month 
Seasonal rainfall 
Month 
Seasonal rainfall 
1916-17 
1917-18 
1918-19 
1916-17 
1917-18 
1918-19 
September... 
October_ 
November_ 
December... 
January_ 
February.. 
Inches 
1.60 
.37 
.55 
2. 40 
.97 
2.16 
Inches 
0 
0 
.71 
.31 
.47 
2.45 
Inches 
5.17 
.32 
2.39 
1.74 
.96 
3.06 
March.. 
April. 
May... 
Total.. 
Inches 
0.76 
.15 
.06 
Inches 
2.90 
.38 
.09 
Inches 
1.94 
.08 
0 
8.92 
7.31 ! 
I 
15.66 
The growing of sugar beets as an annual crop is by far the more important 
phase of the industry in this country at the present time. The preceding dis¬ 
cussion of the damage caused by curly-top is only in regard to this phase of the 
industry. The growing of sugar-beet seed is another phase of the industry in 
which curly-top is an important factor. Because of the biennial nature of the 
sugar beet, the plants must grow at least a part of two seasons in order to flower 
and produce seed. According to the most successful procedure under Cali¬ 
fornia conditions the seed is planted in summer or early fall. The young plants, 
or stecklings, are then transplanted to the seed-beet fields in winter or early 
spring. In the summer and fall months the stecklings are very apt to become 
infected if leafhoppers are present. The selection of suitable plants for trans¬ 
planting is based chiefly on size of roots. Naturally, therefore, many plants 
which are infected late are on that account about normal in size and are trans¬ 
planted to the seed fields. The result of this procedure is that a considerable 
proportion of the transplanted plants fail to produce flower stalks or produce 
only dwarfed, diseased stalks. An example of the part the disease plays was 
observed in the seasons of 1918 and 1919. The seed was planted late in the 
summer of the first year in a region infested with beet leafhoppers. As the 
stecklings grew up in the late summer and fall it was evident from the number 
of leafhoppers present and the cases of the disease scattered through the field 
that a considerable proportion of the plants had been inoculated. The steck¬ 
lings were transplanted in the following winter and early spring with the result 
that because of curly-top about 30 per cent of the plants failed to produce seed. 
No appreciable injury of seed beets due to infection in the second season of 
growth has been noted. When healthy stecklings are planted in the winter or 
early spring they grow to such an extent during the cool months before the 
leafhoppers appear or become abundant that there is practically no danger of 
injury from the disease. ^ This observation is based on conditions in California, 
but it probably holds true also for other districts where seed beets are grown. 
In addition to the direct loss due to the damage to the beet crops, great 
financial loss is involved when sugar factories are built in districts which prove 
unsuitable. The cost of building and later dismantling and removing the fac¬ 
tory to another locality, together with the loss of capital invested in other im¬ 
provements and equipment, must also be considered. Two instances in Cali¬ 
fornia alone are known in which factories were dismantled and removed because 
of the inability to grow beets on account of curlv-top. 
