22 MAINE AGRICULTURAL EXPERIMENT STATION. I9I4. 



produced in the early spring from the myceHum of the fungus 

 which had remained aHve in the diseased branches over winter. 

 The latter might have been the case with some of the later 

 germinations but under the climatic conditions which exist in 

 this State it does not seem possible where the tests were made 

 early in March. 



Young apple trees growing in the greenhouse were inoculated 

 by spraying the foliage with spores produced from cultures of 

 the fungus obtained from diseased limbs. In a month or 6 

 weeks the leaves of these trees were badly attacked by apple 

 scab. Scab did not develop on other young trees growing in 

 the same greenhouse and which were not so inoculated. 



From the above it would seem evident that in this climate 

 it is perfectly possible for the apple scab fungus, and the conidia 

 oif the same, to live over winter on diseased twigs and water 

 sprouts, and that this form of the disease may be an important 

 factor in the production of early spring infection where suscep- 

 tible varieties of trees are grown. In this connection it is a 

 matter of extreme practical importance to know how effective a 

 dormant spray of bordeaux mixture or lime-sulphur is in con- 

 trolling this phase of the disease. In, the laboratory it was 

 found that simply dipping the affected twigs for a few seconds 

 in the winter strength lime-sulphur sufficed to kill all living 

 spores, but no results of a regularly conducted spraying experi- 

 ment were secured. However, certain observations made by 

 the writer furnish some rather interesting data upon this sub- 

 ject. 



These observations were made upon a block of four-year-old 

 Mcintosh trees in an orchard belonging tO' Mr. F. H. Morse of 

 Waterford. This consisted of 40 trees, 5 rows of 8 trees to 

 the row, set on an acre of land. They had been well fertilized 

 and cultivated, were 7 to 8 feet tall and were healthy and vigor- 

 ous with the exception that several limbs on practically every 

 tree had been attacked by ' scab the season before. Some of 

 these were so severely injured as fo kill them back for several 

 inches. However, the badly attacked trees were by no means 

 confined to any one part of the block. They were visited about 

 the first of July. 



