1890.] PUBLIC DOCUMENT — No. 33. 225 



to be a one-half per cent, solution of sulphate of copper, 

 prepared by dissolving it in water in the proportion of 

 one pound to twenty-five gallons. The grain should be 

 thoroughly wet with this solution, and allowed to soak in it 

 for from twelve to twenty-four hours. It may then be 

 spread ovit for a few hours, till dry enough to be readily 

 sown. This treatment is very eflScacious and inexpensive. 



2. The sjiot disease of sugar beets appeared on the leaves 

 of that crop about the end of June, in the form of dead, dry, 

 circular patches, from one-eighth to three-eighths of an inch 

 in diameter. These patches are the result of the death of 

 the leaf tissues, caused by their invasion by a fungus 

 mycelium. While a few patches would do little harm on the 

 large leaf of a beet, they often become so abundant, as in 

 the present case, as to destroy a large part of the tissue of 

 the leaves. Since, as we have seen, the leaves, being the 

 chlorophyll-containing organs, are those on which the plant 

 depends for its supply of organic food material, it is evident 

 how serious for the plant must be the loss, during its time 

 of active growth, of a laroe fraction of its working leaf 

 surfoce. In the case under notice, the spots gradu- 

 ally extended and increased, until, in August, the leaves 

 died completel}^ from the violence of the attack. By this 

 time, however, the roots were so well grown that they were 

 able to put out promptly a fresh growth of leaves, which 

 continued through the rest of the season, though themselves 

 affected somewhat by the spot. Clearl}^ the production of 

 new leaves must have involved the conversion, for that pur- 

 pose, of a considerable amount of stored material from the 

 root, which ought to have remained there. This loss, with 

 that due to the diminution of active surface on both sets of 

 leaves, must very materially reduce the amount of solid 

 matter in the roots, and lessen their feeding value in pro- 

 portion. 



Two fungus forms appeared on the spots on the station 

 beets, both of them belonging to the Imperfect Fungi. Up 

 to about the 10th of July, the most al)undant form' was that 

 known to botanists as Septoria Betce West., while after that 

 time the chief form, and, late in the season, apparently the 

 only form, was that known as Gercospora heticola Sacc. In 



