DISEASES DUE TO FUNGI 109 
soon die and hang down the stem. Tiny heaps of spores 
are produced on the diseased areas on both sides of the 
leaf. Control is a difficult matter, and infected plants 
should be destroyed immediately. Spraying with a 
copper fungicide is recommended as a means of protecting 
the healthy plants. 
Powdery Mildew of the Chrysanthemum.—Chrysan- 
themums grown under glass frequently suffer from 
this disease, due to Oidium chrysanthemi Robh. The 
leaves become covered with 
a white, powdery, fungal 
growth. The presence of the 
disease is conditioned by a 
moist atmosphere, and atten- «@@& 
tion to ventilation and the 3 
massing of the plants so as to 
encourage an efficient circula- 
tion of air will do much to 
limit its development. Dust- 
ing with sulphur powders or 
spraying with liver of sulphur 
and flour paste has proved 
successful in checking its 
rapid spread. 
Chrysanthemum Leaf Spot. rie. 30. Septoria leat spot of the 
—Septoria  chrysanthemella teat, () a pyeutdiun, (0) spores. 
Cav. (Sacc.) causes a leaf spot disease of the chrysanthe- 
mum (Fig. 30) which is distinguished by the presence 
of small dark brown spots, bearing pycnidia or fruiting 
bodies which show as minute black points. The spots 
grow rapidly and coalesce, causing the leaves to curl at 
the edges and to fall prematurely. Leaf spot is not a 
common disease in this country, although it has been 
recorded several times. In America and Europe it is well 
known to growers. Diseased leaves should be removed 
and burned, and the plants sprayed with liver of sulphur. 
