456 DISEASES OF CULTIVATED PLANTS 



conidiophore bears at its apex a single elliptic-oblong, 1-5- 

 septate, most frequently 3-septate, brown conidium averaging 

 36X15 fi. 



Ascospora stage. Perithecia black, depresso-globose, not 

 papillate, and Aouth indistinct or absent, 100-130 //. diam., 

 spores elliptic-fusoid, ends obtuse, continuous, hyaline, 5-6- 

 guttulate, 15x5-7 /*. 



i i The early spring infection is undoubtedly due to conidia 

 produced on the shoots that were attacked the previous 

 season. All such should be removed. - Spray with self-boiled 

 lime and sulphur wash. 



Prillieux, Malad. des Plantes Agric., 2, p. 337 (1897). 

 Vuillemin, Journ. de Bot.> i, p. 315 ; 2, p. 255 (i! 



PHLEOSPORA (WALLR.) 



Perithecia imperfectly developed, often formed from the 

 modified matrix. Spores elongated, 2-many-septate, hyaline. 



Septoria is distinguished from the present genus by the 

 presence of a distinct perithecium. Approaching the genus 

 Septogloeum in the rudimentary perithecium if indeed distinct. 

 In the last-named genus the perithecial wall, as such, is 

 absent. 



Minute fungi growing on leaves. 



Hawthorn leaf scorch, caused by Phleospora oxyacanthae 

 (Desm.), forming crowded, yellowish spots on hawthorn 

 (Crataegus oxyacanthae) leaves; spreads rapidly, giving to 

 the tree or hedge the appearance of having been scorched. 

 The minute, imperfect perithecia are mostly present on the 

 spots on the under surface of the leaf. The hyaline, many- 

 septate spores ooze out of the perithecia in the form of a 

 viscid tendril, and measure 70-80 x 5-7 p. 



The fallen leaves should be collected and burned. Spray 

 with potassium sulphide to arrest the spread of the disease. 



Phleospora ulmi (Wallr.) forms small spots on living leaves 

 of the elm. Spores almost cylindrical, becoming 4-septate, 

 50-58x5-6 /A. 



Phleospora aceris (Sacc.) causes reddish specks or blotches 

 on living leaves of sycamore and maple. Spores narrowly 

 subclavate, 3-septate, 20-28x5 p. 



