92 ilAINE STATE COLLEGE 



^ As this fungus has been very abundant in southern and south- 

 western Maine during the past season, and is almost sure to appear 

 again, we give for the benefit of all concerned the following account 

 of the disease : 



NATURE AKD DISTRIBUTiON. 



This fungus has two stages in its life history, which are found 

 upon very different plants. The Gymnospornagixi.in or Cedar Apple 

 stage, which occurs upon the Red Cedar and Low Juniper, mem- 

 bers of the Order Conifers, and is known as Gymnosporanymm 

 clavipes, C & P. The Ho^stelia or Rust stage (known as Fcestelia 

 aurantiaca, Peck.) which occurs upon the Sugar Pear, (Amelan- 

 chier) Pear thorns (Crataegus j, Choke Berry (Pyrus arbutifolia) 

 and the cultivated quince and apple trees, all plants belonging to 

 the Order Rosacea. 



The first stage of the disease is probably as widely distributed 

 as cedar trees and has been detected throughout the New England, 

 Middle and most of the seaboard .Southern States. 



This stage of the disease is the forerunner of the E'Astelia or Hust 

 stage, which cannot occur without it. The Red Cedar and Low 

 Juniper are, therefore, responsible for the occurrence of the Roestelia 

 or Rust upon quince and apple trees. After the Hcestelio. has become 

 established in quince and apple trees it is prohaV.y perenrdo.l . that is, 

 the mycelium may live in the twigs and produce spores from year 

 to year. 



The spores produced by the Roestelia upon plants of the Order 

 Rosacea; can only grow when they find lodgment under proper con- 

 ditions upon cedar trees, and then they produce the gy-mnosporoji- 

 gium stage or cedar apples. 



The mycelium of the gymnosporangium is abundant causing the 

 twigs of cedar trees to become swollen and much branched and the 

 leaves to swell to double their natural size and become pointed and 

 spreading. This is well shown in Fig. 1. A, which represents a 

 diseased branch with enlarged and pointed leaves and bearing the 

 reddish or brownish sporiferous masses. Fig. 1, B, shows a 

 normal branch and Fig. 1, C, one of the ovate, t«vo-celled spores 

 which is germinating. 



