Notes From the Field.

BY B. T. GALLOWAY, WASHINGTON, D. C.

Sterility of Pear and Apple Flowers as a factor influencing fruitfulness. In the course of some investigations of pear blight carried on by the Department of Agriculture, it was shown that when insects were excluded from the flowers many varieties of both pears and apples failed to set fruit. This discovery led to experiments which seemed to clearly prove that most of our well-known varieties of pears and apples are practically self-sterile; in other words, to obtain a good crop of Bartlett pears, for example, it is necessary for the flowers to receive pollen from some other variety. A Bartlett pear flower fertilized with its own pollen, if it develops into a fruit at all, will be so dif ferent from the typical form as to be scarcely recognizable. The evidence at hand seems to clearly indicate that pollen from most of the well-known varieties will fertilize the Bartlett flower and produce typical Bartlett fruits. On the other hand, Bartlett pollen is thoroughly capable of fertilizing other varieties, such as Anjou, Winter Neelis, etc., the result being in every case the production of typical fruits of the kinds in question.

These statements are not based on a few scattered experiments; on the contrary they are made after hundreds of tests, extending over a period of nearly three years. The whole of the evidence at hand resulting from this work may be briefly summarized as follows:

( 1 ) The majority of the cultivated varieties of pears and apples require cross-fertilization in order to bring about successful fruitage. By cross-fertilization is meant the transfer of pollen from a different horticultural variety, and not from a different individual of the same variety.

(2) Bees and other insects perform the work of cross-fertilizing. (3) The weather at the time of flowering has an important influence on the visits of bees and other insects, and through these upon the setting of the fruit.

Horticulturists will see at a glance the practical application of the foregoing principles. No single variety known to be partially or wholly self-sterile should be planted in large blocks without introducing others known to be good fertilizers. Unquestionably the failure of many orchards to fruit can be traced to this cause, and the remedy in such cases is to introduce, either by top-grafting, budding or planting, varieties known to be active fertilizers. Of course, judgment must be

used in the selection of pollenating varieties, otherwise there may be discrepancies in the time of blooming, which will render them valueless so far as the object in view is concerned.

PEACH YELLOWS AND ROSETTE.

Missouri is fast coming to the front as a peach-growing State, and for this reason the greatest care should be exercised in the matter of keeping out this crop's two worst enemies, namely, yellows and rosette. The former disease to a certainty extends as far west as Central Kentucky, and it is probably only a question of time when it will cross the Mississippi, if it has not already done so. Rosette, which is even. more virulent than yellows, already occurs in parts of Kansas, but as yet it has attracted very little attention. This disease is causing the most serious trouble in Georgia, where it attacks both peaches and plums, killing the trees usually in about five months. Rosette in many respects resembles yellows, the principal difference being an absence in the case of the former of premature fruit, and a much more tufted growth.

No remedy for either yellows or rosette is known, but by proper precautions it is believed that regions now free from the diseases may be kept so. Briefly the precautionary measures we should recommend are as follows:

1. Procure no nursery stock from regions in which yellows exists. 2. Import no pits, buds or grafts from such regions.

3. Buy only from responsible nurserymen who have grown their own stock and cut their buds from healthy trees.

4. Destroy the first cases of yellows or rosette on sight, and continue the fight along this line.

For five years the United States Department of Agriculture has been experimenting with fertilizers to determine whether yellows could be prevented or cured by the addition to the soil of various fertilizers. "Potash, soda, magnesia, phosphoric acid, wood ashes, lime, nitrogen and other plant foods have been used repeatedly, separately and together, often in large quantities, and frequently on as many as 50 or 75 trees, healthy and diseased. Some of the diseased trees improved in appearance and probably lived longer than they would otherwise, but none of them recovered. Neither was it possible to keep healthy trees in a state of health." These experiments, therefore, carried on under widely different conditions and in the heart of the great peach region of Maryland and Delaware, seem to clearly indicate that yellows cannot be prevented or cured by the application of any of the usual forms of plant food.