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Show FAILURE OF TREES TO SET I Trouble Is Due to One or More of Several Sev-eral Causes Many Varieti :s re Self-Sterile. (By TV. W. HOBBrN'S, Department of Bnt:iny and Forestry, Colora-le Asri-euliural Asri-euliural College.) The failure of orchard trees to set fruit, in spite of the fact that an abundance of blossoms was produced, is due to one or more of several causes. These are as follows; 'Self-Sterility Many varieties of apples ap-ples and pears are 'self-sterile. That is, they are not capable of setting fruit properly unless pollen from another an-other variety is used. For example, Bartlett and Keiffer pears, in many localities, when planted in solid blocks, give less satisfactory results than when they are planted with such varieties as Lawrence, Duchess and Anjou. With apples and pears it ia good practice to mix varieties. However, How-ever, if varieties with proper affinities affini-ties are selected, one variety to fur-! fur-! nisb the pollen is as good as a number. num-ber. Frozen Pistils The pistil, .which Is the part of the flower to develop fruit, is more easily frozen than other parts of the flower. Hence the pistil J may often be frozen while other fiow-" fiow-" er parts are not affected; consequently, consequent-ly, blossoms are formed, but fail to set fruit. Weak Trees Trees in a weak condition, con-dition, although blooming abundantly, often fail to set fruit. Rain and Snow The pistils may be mechanically injured and the, pollen washed away by rain or snow at the time the blossoms are open. Excessive Growth of Wood Blossoms Blos-soms often drop in great numbers when the tree 13 forming excessive amounts of wood. Overabundance of nitrogen fertilizers. fertiliz-ers. Diseased buds. Spraying Heavy spraying of trees, especially before pollination, has in some few instances resulted in a loss of blossoms. This is not serious, however. how-ever. , |