. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 6 BULLETIN 104, U. S. DEPARTMENT OF AGRICULTURE. (2) Inasmuch, as they consume large quantities of pollen, do they thus work injury to beets? (3) Do they injure the floral organs of beet flowers? To be effective agents in the fertilization of beet flowers, they must do more than convey pollen from one flower to another on the same spike, stem, or plant; they must bring about true cross-pollination. Although already late in the season when the foregoing observa- tions were made, experiments were at once planned to ascer
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 6 BULLETIN 104, U. S. DEPARTMENT OF AGRICULTURE. (2) Inasmuch, as they consume large quantities of pollen, do they thus work injury to beets? (3) Do they injure the floral organs of beet flowers? To be effective agents in the fertilization of beet flowers, they must do more than convey pollen from one flower to another on the same spike, stem, or plant; they must bring about true cross-pollination. Although already late in the season when the foregoing observa- tions were made, experiments were at once planned to ascertain whether pollination and fertilization might be effected through the agency of thrips. To this end several vigorous seed beets, still in bloom, were selected. On August 7 and 8, 1911, the largest buds en a number of spikes were emasculated, the smaller and more immature buds being trimmed off. This work was done at the stage when the sepals were just about to separate at the tips and disclose a tiny yellow spot of the anthers, and it was performed under a pollinating tent in order to exclude flying insects and wind- carried pollen (fig. 4). As each set of buds was emasculated it was at once covered with a white manila paper bag, 4 by 6 inches in size. A tuft of absorbent cotton was first wrapped carefully about the spike some inches below the buds. The bag was then drawn over the spike until the emasculated buds were situated in- side the bag near the top, while the mouth of the bag reached well below the buds and came in contact with the wrapping of cotton. The mouth of the bag was then folded diagon- ally in such a manner as to pinch the cotton-wrapped stem in one corner; then it was folded a second time to make tight contact. Metal clips were finally set along the edge of the double fold to secure it (fig. 5). The stems bearing these spikes were tied to stakes to prevent too much movement and to keep them in an upright posi- tion. Before covering the spikes a close searc
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