100 VEGETABLE GROWING IN NEW SOUTH WALES. 



attacked should be carefully carried out, arid though this will destroy many, 

 large numbers will still remain in the soil and in small pieces of broken leaves, 

 As these retain their vitality for a year, or even two or more years where 

 blight is severe, a rotation of crops (see page 22) should be practised. 



The first injury from this Disease is the loss of leaves, but if the weather 

 becomes unfavourable to the fungus after an attack has commenced, the 

 affected plants may recover and produce sufficient new foliage to carry the 

 bulbs to maturity, especially if the attack has been early. Spraying with 

 weak Bordeaux mixture (see page 128) should be done to prevent infection. 

 When the early appearance of the disease is noticed only in isolated areas, 

 several thorough sprayings should be given to these areas first. Sprayings 

 to prevent infection should be commenced early and given about every four 

 weeks, but, in rainy weather, about every two weeks. 



Anything that tends to weaken the onions, such as too much moisture or 

 shelter, should be avoided. Seed should be free from bits of leaves and 

 stems which may harbour the disease, and before sowing should be soaked 

 for half an hour in a solution of formalin 1 part, and water 200 parts. This 

 will also prevent the introduction of onion smut, which does not yet occur in 

 New South' Wales. 



Dry Rot of Potato. 



A very common form of potato disease is a dry, whitish, crumbling 

 condition of the tubers. If such tubers are kept dry they mostly shrink 

 up and become hard, whereas if kept at all moist, or stored -in a damp 

 place, they soon become covered with an abundant, white, felt-like growth 

 of fungus- threads. Investigations have proved that this dry rot ean be 

 produced by many species of Fusarium, some of which are true parasites 

 and can entirely destroy the tubers, while others cannot by themselves 

 destroy the tubers, but only assist in the destruction after the tubers 

 are attacked by other fungi and bacteria. The species causing dry rot are 

 not the same in all countries, and although some occur in both Europe and 

 the United States of America, others are confined to one or other of those 

 areas. Where there is any suspicion that the seed may be diseased, it would 

 be advisable to cut all tubers, and any showing a brown ring under the 

 surface should be rejected, as also should those showing any signs of surface 

 rotting. As the fungi can live for some time in the soil, fyadly infected 

 areas should have a rotation of crops (see page 22). 



Early Blight of Celery and Parsnip. 



This disease, as its name infers, occurs early in the season, [and produces a 

 more defined spotted appearance than the late blight (see page 102). When 

 the spots become numerous on a leaf it begins to turn yellow, and assumes a 

 characteristic ashen colour and velvety appearance. When a leaf becomes 

 badly attacked it wilts and dries, and numerous spores are produced over 

 the surface, particularly during muggy weather. 



Early spraying with weak Bordeaux mixture (see page 128) will control this 

 isease. 



