104 THE ORCHID REVIEW. [APRIL, 1915, 
glossums, as it produces spores on the under surface of the leaves, causing 
yellow patches on the surface. I think this disease is largely due to 
excessive moisture. The best cure for this is sponging. Spotting and 
decaying of foliage iscommon. This is due to mechanical agencies, such 
aS excessive moisture and insufficient ventilation, perhaps also to lack of 
light. Some Orchids revel in sunshine, and when cultivated in a house 
that is too shady become weak, and finally die. To prevent this give a 
more sunny position. It is rare to find much evidence of disease in 
‘Nurseries, as it obviously means loss to the grower, both in its effect upon 
‘visitors and in the loss of plants, some of which are very valuable. Some 
particular disease will occasionally trouble a grower, this, perhaps, being 
due to incorrect cultural methods. 
‘The commoner insect pests are :— : 
Turip.—This pest is most prevalent. In Belgium we have different 
‘systems for killing thrip, the best one to my mind being effected by means 
of tobacco laid on wire netting placed beneath the stages. Another 
method is to fumigate with nicotine. ; 
RED SPIDER.—This is largely due to dry atmospheric conditions. I 
once paid a visit to a nursery near Ghent, and there I saw a house full of 
Phalznopsis Sanderiana literally smothered with red spider. This was 
entirely due to a dry wall which they failed to damp. The best remedy is 
Sponging with water or insecticide. 
ScaLE AND MEALY Buc.—These are common, but are easily kept in 
check by washing and cleanliness, 
WoopLicE can be trapped with sliced potatoes, which should be 
examined each morning. SLucGs are caught with beer, and cockroaches 
destroyed with phosphor paste. 
ORCHID FLY (Isosoma Orchidearum) lays its eggs in the young growths 
of Cattleyas and Lzlias, and if it become numerous is most destructive: 
The remedy is to cut away the affected parts and burn them before the flies 
escape to lay more eggs. 
A BEETLE (Baridius aterrimus) is sometimes present on imported 
plants. of Dendrobium Phalznopsis, and on Phalznopsis from Singapore 
and Burmah. Although not very frequent it is most destructive, and the 
only method of destroying it is to watch the plants affected. 
This vast industry is an international one. Apart from the scientific 
interest attached to Orchids, many people grow them for their beauty a0 
peculiarity. Amateurs of all classes, but more especially the affluent 
peoples of the world, make Orchid cultivation their hobby, and from this 
wide-world popularity which the Orchid possesses, has developed the vast 
itrade which now, or did prior to the present debacle, exists in Belgium. 
HENRI PIERRE CHOLLET- 
