150 Commercial Gardening 



comes thicker in texture, more especially on the twigs and berries; in fact, 

 the patches of mildew become so thick and felty that they can be readily 

 scraped off. Later in the season the felt-like patches of mould become 

 studded with small black fruits resembling in size the winter fruits of the 

 European mildew. Some of these remain attached to the mildew on the 

 twigs until the following season, others fall to the ground, but in both 

 instances the spores are liberated in the spring, and are capable of infecting 

 the young shoots of Gooseberries. 



The preventive measures that have proved most satisfactory in com- 

 bating this disease are as follows. Commence spraying with a solution of 

 potassium sulphide ( = liver of sulphur) 1 oz. in 3 gall, of water, just 

 when the leaf buds are expanding, and repeat about every ten days, or 

 more frequently if heavy rains occur. This method is adopted as a means 

 of preventing the spread of the disease by means of summer spores. With 

 the object of eradicating the disease, a different line of treatment should be 

 pursued. Somewhat early in the autumn every shoot should be pruned 

 back for at least 6 in. This practically removes all the shoots bearing 

 mildew and winter fruit of the fungus. In some places the prunings are 

 dumped in heaps to be disposed of at some convenient time. In other 

 places the prunings are not collected at all, but left lying on the ground 

 around the bushes. The prunings should be collected and burned at once. 

 The time to prune is somewhat difficult to determine. If it is done too 

 early in the season, and is followed by mild weather, new shoots are some- 

 times made which may become infected, and so carry over the disease to 

 the next season. If pruning, on the other hand, is unduly delayed, many 

 of the winter spores drop to the ground, and, unless due precautions are 

 taken, endanger the bushes for the following season. This can be guarded 

 against by digging over the ground during the winter, by which means 

 all winter fruit of the fungus, whether lying on the ground or on fallen 

 diseased leaves, are buried and rendered harmless. In places where the 

 methods outlined above have been honestly carried out, the disease has 

 been reduced to a minimum, or altogether banished. 



European Gooseberry Mildew (Microsphcera grossularim). This is 

 a white superficial mildew, appearing on the leaves, and sometimes but 

 rarely passing on to the fruit. It grows on both surfaces of the leaf, 

 and forms a very thin film which remains permanently white. Soon 

 after the appearance of the mildew its surface becomes minutely powdery 

 as if sprinkled with flour. This dusty appearance is due to the presence 

 of myriads of the summer form of fruit, which are conveyed by various 

 means to adjoining bushes, and thus the disease spreads apace unless 

 checked. 



At a later stage minute black bodies, smaller than the head of a small 

 pin, may be seen scattered over the surface of the white mouldy patches. 

 Theso are the winter form of fruit, which remain on the dead leaves until 

 the following spring, when the spores are liberated and infect the young 

 leaves. 



