FIFTY-FIKST ANMAL RErORT. 75 



Question: Would a certain application at this time, of strong sub- 

 stance damage the trees? 



Answer: I could not tell you without first seeing what the trouble 

 is. I really do not think, however, that an ordinary spray would hurt 

 at this time. 



Question: Is the affliction of the trees something in the soil? 



Answer: Could not tell without seeing the trees. 



Mr. Hawley: Were there apple orchards in Michigan that had perfect 

 control of the codling moth? 



Mr. Button: Yes, there were many of them, but they were all thor- 

 oughly sprayed. 



Mr. Brooks: Would the dormant spray answer for the pre-pink spray? 



Mr. Button: I will not recommend it at this time. 



OFF-YEAR BEARING OF APPLE TREES. 



PROF. E. J. KRAUS, UNIVERSITY OF WISCONSIN, 



It is a fairly common idea among fruit-growers that the habit of 

 alternate bearing is a fixed one and that little or nothing can be done 

 to prevent it or to overcome it, when once established. True it certainlj- 

 is that some varieties of apples and other tree fruits are very likely to 

 assume this habit early in life, and continue in it for long periods of 

 years, although there are many varieties which are notorious for annual 

 production. Many varieties which are indifferent in quality and many 

 other respects are grown commercially, largely because they possess 

 this valuable trait, while other excellent sorts are discarded because of 

 the fact that they strongly tend to alternate bearing. It is a matter of 

 interest to recall that some varieties tend toward annual bearing in 

 certain sections, whereas in others they bear alternately, though as a 

 rule, any given variety is likely to behave in much the same way in 

 widely separated regions; any differences in behavior being due to varia- 

 tions in cultural practices, in large measure. Even in the case of those 

 varieties having pronounced tendencies toward alternation in bearing, 

 such alternation is not likely to be shown in the first few crops produced; 

 the tendency becomes intensified as the trees grow older and is most 

 pronounced in the cases of those trees which are not under the highest 

 state of culture, or are suffering from neglect. Furthermore, even 

 though the alternating habit is pronounced, it is possible for one year 

 of heavy bloom to be followed by another, in case there is a severe freeze, 

 or some other climatic condition prevails which causes the death of- a 

 large proportion of the blossoms or buds to fall, during such a year of 

 heavy bloom. 



These facts last mentioned, and the fact that certain varieties wliicii 

 tend toward alternate bearing may be made to bear annually, lead one 

 to suspect that the cause of alternate bearing is largely tied up with the 

 state of nutrition of the trees, and that if this is the case, it should be 

 possible, by learning something of the inter-relations of nutrition, growth 

 and fruitfulness, to arrive at some knowledge as to the means of regu- 

 lating them, so that there would be an annual production of flowers and 

 fruit. This view is strengthened by the fact that when flowers or buds 

 are removed from trees at a very early stage (certainly before the 3'oung 



