Gardening for Amateurs 



553 



plants, nevertheless, remain very dwarfed, 

 and are practically worthless for flower 

 production. 



Remedies. Infection takes place through 

 the soil. The fungus may be introduced in 

 manure, and it is generally present in soils 

 that are rich in organic matter. Sterilising 

 the soil by baking for seedlings, steaming it 

 to a temperature of 180, and soaking the 

 soil where the plants are to grow about 

 three weeks before sowing or planting with 

 1 gallon of carbolic acid or Lysol to 200 

 gallons of water, have been advised as pre- 

 ventives. For general purposes we advise a 

 1 per cent, solution of commercial formalin 

 (formaldehyde 40 per cent.). This should be 

 used on the ground as prepared for sowing 

 or planting at the rate of 1 gallon per square 

 yard, covering over with old sacking for four 

 days to keep in the fumes. Then uncover 

 the soil and expose for a fortnight, after 

 which fork over and sow or plant. 



Wilting. This disease usually attacks 

 young plants. The seeds germinate normally, 

 and everything looks promising ; however, 

 when the seedlings reach a height of a few 

 inches they suddenly fall over and collapse. 

 Sometimes the plants die at a later stage, 

 but seldom later than the flowering. When 

 pulled out the plants come away with the 

 central part slipped out from the bark, which 

 has been rotted by the fungus. If the col- 

 lapsed plants are allowed to remain on the 

 ground the stems soon become covered with 

 the sickle-shaped spores of the fungus, 

 which are carried by flies to healthy plants. 



Remedies. The fungus must be overcome 

 by timely dressings of lime, and where 

 practical by steam sterilisation, especially 

 for rearing in pots. 



Collar Rot. Plants affected by this 

 disease first show a wilting of the tips and 

 flagging of the leaves, and then fall over and 

 collapse. The fungus causing the trouble is 

 usually confined to the junction of the stem 

 with the soil. It is a soil organism, and 

 occasionally causes root trouble in Clover. 

 It is generally introduced into gardens and 

 fields with animal manures, particularly if 

 they are rank and strawy. The utmost care 

 should be taken to remove and burn all 

 affected plants, and use quicklime freely on 

 the ground. 



Remedies. Dusting the collar of the plants 

 with air-slaked lime acts as a preventive 

 of the disease. On badly infested land the 

 best plan is to strew dry litter over the surface 

 and set it on fire. This treatment may be 

 supplemented by dressing the land with 

 kainit, especially if Sweet Peas have to be 

 grown in the same ground. 



Rhizoctonia Disease. This fungus pest 

 is common to many seedlings, including 

 Sweet Peas. Severely attacked plants have 

 practically no root system. The fungus is 

 characterised by its browning effects on the 

 roots, and in some cases by their total 

 destruction of the root. Sterilisation of the 

 soil by steaming or heating to 180 or 200 

 is the best preventive. 



Powdery Mildew. This disease is some- 

 times very prevalent on Sweet Peas grown 

 under glass, and on plants grown in low and 

 damp situations, or where the plants are 

 disposed too thickly. Ordinarily, however, 

 the disease is not of material consequence, 

 and where it does appear, dusting with black 

 sulphur will prevent its spread. 



Bud Drop. This is not a disease, although 

 a common trouble in the culture of Sweet 

 Peas. It occurs on apparently healthy and 

 well-grown plants. The trouble usually 

 arises from the use of too highly nitrogenous 

 food supplies, in which the mineral elements 

 are too low, especially the phosphoric and 

 potassic. An application, therefore, of phos- 

 phoric acid or superphosphate of lime and 

 sulphate of potash alongside the row will 

 usually control this trouble within a week 

 or ten days, always provided sufficient 

 moisture obtains in the soil to render the 

 fertilisers available for reception by the 

 roots. 



Root Galls. The presence of galls on 

 the roots may render applications of nitrogen, 

 phosphoric acid and potash of no avail to 

 the plants, inasmuch as the tenants of the 

 galls interfere with the transmission of those 

 elements to the parts above ground. The 

 plants in consequence stop growing, and show 

 a dwarfed and sickly appearance. Such 

 plants may produce a few blooms, which 

 are of little value, since they are borne on 

 small peduncles, and the plants gradually 

 dwindle away. 



The galls are either formed singly or they 



