Insect Pests and Fungoid Diseases. 425 



until the pods arc attacked, it first appears on the stem, on which it makes 

 brownish sunken patches, and sometimes on the leaves, the diseases parts 

 of which soon become dry and drop out, leaving irregular holes. If the 



Bean Pods, showing Canker. (Reduced.) 



disease can be detected and dealt with at this stage, before the pods are 

 formed, the crop may be saved. Infected seed should never be sown or 

 the plants will probably be killed before they reach the flowering stage. 



Treatment : Remove and burn all diseased plants before spores are 

 produced. Spray in the early stages with Bordeaux mixture at half the 

 normal strength ; after the pods are set and until they are half grown spray 

 with sulphide of potassium solution. 



Avoid planting beans in damp low-lying places and use only healthy seed. 



BEET RUST (Uromyces betce). This fungus sometimes badly attacks 

 the foliage of beet, and seriously cripples the growth of the plants. It may 

 be recognised by the rusty-red powder (spores) produced from numerous 

 small raised points on the diseased leaves. 



Treatment : Repeated sprayings with Bordeaux mixture will keep the 

 rust from becoming serious. When the beet is lifted all diseased leaves 

 should be collected and burnt. 



CABBAGE BLACK ROT (Pseudomonas campestris).This disease is 

 caused by bacteria ; it attacks cabbages, cauliflowers, sprouts, turnips, and 

 all other members of the crucifer family, causing the plants to rot into a 

 pulpy, foul-smelling mass. The bacteria enter the plant through wounds, 

 injured leaves, broken roots, or through the water-stomata of the leaves. 

 They multiply rapidly and work into the leaf-stalks and stems, causing 

 blackening of the vascular bundles and rotting of the plants. 



It is considered that the disease is sometimes introduced with the seed. 



Treatment : All diseased plants should be carefully collected and 

 burnt; they should never be given to stock or put on dung or rubbish 

 heaps, or a further infection of the land will follow sooner or later. Des- 

 troy all cruciferous weeds. 



Dress infected soil with lime and keep clear of cruciferous plants for 

 some years. 



Previous to sowing, doubtful seed should be soaked for 15 minutes in a 

 solution of corrosive sublimate, 1 part to 1,000 of water (loz. to 6| gals.). 



CELERY LEAF DISEASES. There are three fungoid diseases which 

 attack the leaves and stems of celery, thereby causing more or less serious 

 damage to the crop. 



I. Cercospora Apii (Rust or Sun Scald). This disease usually appears 



