92 VEGETABLE GROWING IN NEW SOUTH WALES. 



Spores from diseased spots on stems and leaves may fall on the pods, where 

 in the presence of moisture and a sufficiently high temperature, they germin- 

 ate rapidly and produce the spots, which enlarge and darken until nearly 

 black. The dead tissue dries and shrinks. Spores are produced bv the fungus 

 in these spots in great abundance, and ooze out, forming pink masses held 

 together by a mucilage, which when dry, sticks them to the spot. When dew 

 or rain falls on these spots the mucilage is dissolved and the spores set free in 

 the water. At this time any disturbance of the bean plant will scatter these 

 spores to other plants, and for this reason beans should not be cultivated nor 

 handled in the early morning while the dew is still on them or after a shower. 



Since diseased pods and stems left in the field provide infection for the 

 new crop, all diseased plants, leaves, and pods should be collected and burnt. 

 Only clean seed should be used in any ftiture planting ; it should be 

 obtained from some source known to be free from disease. 



These are the best preventives, and if they are rigidly carried out the new 

 crop may be free from disease. 



As a further precaution all seed should be disinfected. The most 

 satisfactory dip is a solution of about 1 oz. corrosive sublimate or mer- 

 curic chloride in 6-J- gallons of water. The seed should be soaked in this for 

 ten minutes. This method of disinfection is also of great service in check- 

 ing other diseases. 



/ \ 



i A rotation of crops (see page 22) and spraying with Bordeaux mixture 



(see page 128) have been found to keep the disease in check, but it is best 

 perhaps to pull up and destroy a crop affected with this disease. 



Soil well fertilised with stable manure some time previous to planting has 

 been beneficial in promoting active plant growth and also reducing disease, 

 The grower should also be on the look out for resistant varieties selecting 

 seed from any plants that show resistance to the disease at any time. The 

 wax podded varieties are less resistant than others. 



Asparagus Rust. 



This disease does not attack the shoots which are cut for market, but is found 

 on those green ones which are allowed to develop after cutting has ceased. 

 Affected tops become reddish-brown in colour, and on the stems numerous 

 small, reddish, pustules appear. These contain the spores of the rust fungus, 

 1 n severe cases the tops turn yellow and the needles fall prematurely. The 

 plant, therefore, fails to manufacture and store up the necessary foods 

 resulting in a reduction of subsequent yields. 



The occurrence of the disease is closely allied to certain weather conditions. 

 Rust is most frequently found during seasons of insufficient rainfall, or on 

 soils which dry out rapidly ; hence it may be kept in check by irrigation 



