THE APPLE CANKER. 



and wood in the orchard, and the other 

 was unknown Inoculations were made 

 with both forms, and in a few days there 

 was an area of discolored bark around 

 the place of inoculation in each case 

 where the unknown fungus had been 

 inserted. Further inoculations were fol- 

 lowed by the same results. By the close 

 of the season, several of the seedlings 

 were nearly girdled with wounds three 

 or four inches in length, while on the 

 trees, a portion of the wood was laid 

 bare and the dead areas of bark, charac- 

 teristic of the disease, wtre produced. 

 Further experiments seemed to prove 

 that the apple canker is caused by the 

 fungus that produces the black rot of the 

 apple, pear and quince. Some blighted 

 apple twigs were examined, and it was 

 afterward found that mature spores of 

 the black-rot- fungus were abundant on 

 them. Some pear trees, also, which 

 were found to be in a dying condition, 

 were attacked by the same fungus. The 

 spread of the disease was from the top 

 downward. Fruit of the same fungus 

 has also been found on twigs of some 

 quince trees that grew by the side the of 

 pear trees, although the injury was 

 slight. The canker has also been found 

 on a quince tree in the Experiment Sta- 

 tion orchards, the appearance and effect 

 being much the same as on the apple 

 trees. The disease was also found to 

 be abundant and doing serious damage 

 in the large orchard of Maxwell Broth- 

 ers, near Geneva. A series of experi- 

 ments was undertaken to prove that this 



fungus occuring on these different 

 species of trees is the same and identi- 

 cal with the common black rot of the 

 fruit. 



What Can be Done 1 — Strong evi- 

 dence seems to be produced that a well- 

 known fruit disease will also attack and 

 do serious damage to the trees them- 

 selves. Black rot of the fruit of apple, 

 pear and quince can be held in check 

 with Bordeaux mixture, and there is no 

 reason to think that this standard fungi- 

 cide will fail in this case. Orchards 

 that have been well sprayed with Bor- 

 deaux mixture for several years past, are 

 much freer from the disease than those 

 not sprayed with fungicides. The dis- 

 ease seems to prefer mature trees, and 

 it lives best in the rough bark, till it 

 gains an entrance to the cambium. By 

 removing or preventing the formation 

 of this bark by spraying the limbs 

 with Bordeaux mixture, one favorite 

 breeding place of this and possibly other 

 plant diseases is removed. By keeping 

 the limbs protected with Bordeaux mix- 

 ture, all spores that chance to fall on 

 them will be destroyed. Canker spots 

 once formed cannot be cured, but such 

 limbs should be removed wherever prac- 

 ticable. The rational way to combat 

 apple canker is to spray the limbs 

 with Bordeaux mixture as a preventive. 

 This may be done when the trees are 

 sprayed for apple scab, and an earlier 

 spraying when the growth first starts, 

 would do no harm. — W. Paddock, of 

 Geneva, before W. N. Y. H. Society. 



135 



