PEACH YELLOWS. 297 



ture peaches, and most of them also showed the diseased shoots. Moreover, 

 they were so badly diseased — i. e., bore the shoots or premature peaches on 

 so many branches — that a new or secondary infection in 1888 seemed entirely 

 out of the question. This also seemed improbable from the condition of 

 other trees in the orchards. On the theory of a new infection in 1888, 100 

 per cent of these trees became re-infected in one year, whereas in the 

 orchards as a whole the new cases did not much exceed 10 per cent. 



Fearing I might not have cut early enougn in the season, I repeated this 

 experiment in 1888, in August, in several orchards, particularly in orchard 

 No. 6. This time my incisions were still more severe. Many large limbs, 

 clothed with healthy foliage and bearing a great many sound peaches, were 

 removed for the sake of getting rid of small diseased limbs and making 

 assurance doubly sure. In most cases I removed from one-half to two-thirds 

 of each tree, that part remaining, as well as a large per cent of what was re- 

 moved, appearing to be p.^rfectly healthy. The results of these experiments 

 will be awaited with interest. If they agree with those already detailed, it 

 may be conceded as reasonably certain that the disease cannot be cut out, 

 and it may also be concluded that the trees are not infected through the 

 blossoms, at least not the same year that the premature peaches appear. 



Another way of testing the validity of this theory would be to remove all 

 the blossom buds from healthy trees in infected orchards and note the results 

 for a series of years. This experiment ought to be undertaken in the spring 

 of 1889 in several orchards and in a sufficient number of trees to give 

 unequivocal results. 



WHAT MAY BE HOPED. 



In discussing this question I shall assume that peach yellows is a communi- 

 cable disease. The evidence in favor of such an assumption is stronger than 

 that which has sufficed to hang many a man, and in the absence of direct proof 

 to thf contrary is certainly strong enough to warrant legislative action. In 

 all such cases the public have a right to claim the benefit of the doubt. Even 

 in the present inexact state of our knowledge it is justifiable on the part of 

 State legislatures to make statutes compelling the immediate removal and 

 destruction of all affected trees. 



In peach growing states now free from the disease it would be wise to pro- 

 hibit the introduction of all trees from infected areas. Certainly, if yellows 

 does not now occur in California (and by diligent inquiry I have failed to 

 as3ertain that it does), the greatest care should be taken to prevent its intro- 

 duction, even to the extent of legislation strictly prohibiting the imjiortation 

 of peach trees from the eastern United States. Unless such steps are taken 

 the appearance of yellows in orchards on the Pacific coast is only a matter of 

 time. To what a great extent California is interested in maintaining her 

 present freedom from this disease may be known from the fact that in 1886 

 the peach orchards of that state contained 3,617,973 trees, while the nectar- 

 ine, almond, and apricot orchards contained about one-half as many more. 



The principle objection to such laws is that valuable property will be 

 destroyed. But it is sometimes necessary to destroy property for the preser- 

 vation of surrounding property, or for other reasons. Moreover, it may be 

 urged against this objection (1) that premature peaches are of an inferior 

 quality, generally unfit to eat, and are not eaten to any extent where they are 



