EXPERIMENT STATION BULLETINS. 261 



be some danger of the disease manifesting itself in trees grown from pits 

 produced by portions of trees that as yet show no signs of yellows, but that 

 will exhibit signs of yellows the following year. In most cases, however, 

 the nursery trees from such pits will show signs of yellows the first year 

 and will hardly fail to escape the second, so that on purchasing them the 

 fruitgrower will be able to detect the disease before the trees are planted. 

 It is nearly seventy years since it was claimed that yellows could be 

 spread by the buds, and it is quite certain that if buds are taken from a 

 tree in the second stage of the disease few of them will start at all, and 

 those that do will make but a feeble, unhealthy growth. When from trees 

 that are just coming down with the disease, i. e., when if in bearing a few 

 of the fruits will be premature, the disease may not appear to any extent in 

 the nursery, and an unscrupulous nurseryman will sell the trees that do 

 not show it, in this way scattering the disease. The only safe way is to 

 'purchase trees in localities where yellows either has not appeared or is 

 in check, and where one has good evidence that the pits have come from 

 uninfected regions, and the buds are from healthy trees. If any of these 

 precautions are neglected there is great danger of obtaining the germs of 

 the disease. Many growers claim that if, in carrying a diseased tree from 

 the orchard, a branch rubs against a healthy tree, it will convey the dis- 

 ease, and while this may not be true, it is very probable, and prudence 

 would seem to dictate that the tree be cut up and burned upon the spot, or, 

 if carried to a brush pile outside, it should be removed with great care not 

 to bring any part of the tree into contact with a healthy one. As soon as 

 possible the trees should be burned. In localities where the disease pre- 

 vails, if the affected trees are promptly destroyed the loss seldom exceeds 

 three per cent., while if this is neglected it spreads with increasing virulence 

 until every tree may be destroyed. From the contagious nature of the dis- 

 ease, it can be seen that it can not be guarded against unless there is con- 

 certed action in the infected districts; and to secure this the state of Mich- 

 igan has enacted what is known as the " Yellows Law," which reads as 

 follows : 



THE YELLOWS AND BLACK-KNOT LAW. 



AN ACT to prevent the spread of the contagious diseases known as yellows and black- 

 knot among peach, plum, cherry, prune, almond, apricot, and nectarine trees, or the 

 fruit thereof, by providing measures for the eradication of the same, and to repeal 

 act number one hundred and fifty-eight of the public acts of eighteen hundred and 

 ninety-one, entitled "An act to prevent the spread of yellows, a contagious disease, 

 among peach, almond, apricot, and nectarine trees, and to provide measures for the 

 eradication of the same, and to repeal act thirty-two of the session laws of eighteen 

 hundred and seventy-nine," approved April four, eighteen hundred seventy-nine. 



Section 1. The People of the State of Michigan enact, That it shall be unlawful 

 for any person to keep any peach, almond, apricot, plum, prune, cherry or nectarine 

 tree, infected with the contagious disease known as yellows or black-knot, or to offer 

 for sale or shipment, or to sell, or to ship any of the fruit thereof,- except the fruit of 

 the plum and cherry tree; that both tree and fruit so infected shall be subject to des- 

 truction as public nuisances as hereinafter provided. No damages shall be awarded in 

 any court in the state for entering upon the premises and destroying such diseased 

 trees, or parts of trees or fruit, if done in accordance with the provisions of this act. 



It shall be the duty of every person, as soon as he becomes aware of the existence of 

 such disease in any tree, parts of trees or fruit owned by him, to forthwith destroy, or 

 cause said trees or fruit to be destroyed. 



