Insect Pests and Fungoid Diseases. 427 



heavily with slaked lime or gas-lime immediately the diseased crop is 

 removed. Avoid cropping diseased ground with any kind of brassicae for 

 several years. Drain wet land. Keep down cruciferous weeds. Avoid 

 the use of acid manures, such as superphosphates or dissolved bones. 



CUCUMBER AND MELON MILDEW (Erysiphe Cichoracearum). 

 This fungus produces a white network of mycelium on the leaves of ridge 

 cucumbers, marrows, &c. It is very prevalent after the middle of the 

 season, or earlier when the weather is very dry. 



Treatment : Keep the plants mulched and watered. Spray with 

 potassium sulphide or with Bordeaux mixture at half strength as soon as 

 the mildew is noticed ; or sulphur applied with a powder pump may be 

 dusted over the leaves whilst they are wet. 



CUCUMBER AND MELON ROT. In damp sunless weather melons and 

 cucumbers growing in frames are subject to attack from a fungus (probably 

 a Botrytis) which settles upon and causes rapid decay at the cut ends of 

 the shoots, stubs of leaves, or abraded portions of the stem. If not checked 

 the rot spreads to other parts and destroys the plant. 



Treatment : Carefully cut out and burn all parts affected with the rot ; 

 handle the pieces gently so as not to scatter the spores, or the disease will 

 be spread broadcast. Dress the fresh cut ends with flowers of sulphur, 

 and scatter slaked lime beneath the plants. 



Keep the frames and plants as dry as possible consistent with healthy 

 growth. Put a piece or tile or slate under each fruit to keep it from 

 contact with the damp soil. 



LETTUCE MILDEW (Peronospora ganglioniformis).This fungus 

 most frequently attacks tender young plants growing under damp conditions 

 in a stagnant atmosphere during winter and spring. It appears as a white 

 powdery growth, chiefly on the under surface of the leaves, but if unchecked 

 it spreads over and destroys the whole of the plants. 



Treatment : Winter the plants in a dry and airy situation ; an exposed 

 position with a low screen to break the rough wind is preferable to one at 

 the foot of a wall where the atmosphere is more or less stagnant. Give 

 plenty of ventilation to plants in frames or under cloches. 



Where the plants are badly affected remove and burn them. In case of 

 a mild attack dust the plants with flowers of sulphur applied with a powder 

 pump, or use a very fine spray of Bordeaux mixture or cupram, in either 

 case getting well underneath the leaves. Where disease has occurred, 

 water the ground with copper sulphate solution. 



MINT RUST (Puccinia menthce).Mint in beds is frequently attacked 

 by this fungus. It appears first in orange-coloured raised patches on the 

 leaves and stems, causing them to become distorted and spoiling the crop. 

 The plants become brown and die down early in the season. 



Treatment : Mint appears peculiarly subject to this disease and once it 

 has got hold fungicides are of little or no use ; then the only safe course is 

 clear the whole bed of roots and tops, which should be carefully collected 



