PEACHES AND NECTARINES DISEASES BLISTER FUNGUS. 



107 



Gum. This is a common disease and very destructive to peach and nectarine trees 

 under glass, as well as outdoors. It is caused by a fungus (Coryneum Beijerincki) 

 figured and described in Vol. I., page 235. A condition of the trees favouring its 

 attack is induced by rich soil, over-feeding, unripe wood acted upon by cold, exces- 

 sive vigour, and sudden atmospheric changes, but the opposite extremes of poor soil, 

 want of nourishment, and ill-condition promote gum disease. The best preventive is 



Fig. 30. PEACH BLISTEE OB CTJBL (ExoASCtrs 



DEFOBMANS) . 



Showing affected leaf, and spores escaping from a 

 cell (aseus) below, greatly magnified. 



Fig. 31. PEACH MILDEW (SPH.EBOTHECA PANNOSA). 



"Fruit" central figure. Section of "fruit" with 

 sporidia escaping lower figure. The Oklium leuco- 

 conium or early condition upper figure. 



moderately rich soil and attention to the essential cultural conditions of health. As 

 a remedy, lifting and cutting away the affected parts has proved most effectual. (See 

 " Gum," Vol. I., pages 234238.) 



Mildew. More than one species of O'idium attack the young shoots, leaves, and 

 young fruits, but they are merely a stage in the growth of more highly-developed fungi. 

 (See Vol. I., page 245.) The Oidium form of Sphaerotheca pannosa, namely, 0. letico- 

 conium (Fig. 31, upper figure), form a dense greyish coat over the parts affected, and 



