isfactory root action can be set up.

Propagation, by freeing the recently made parts of the plants from the
old and worn-out back portions, which are not furnished with the roots
necessary to support themselves is one of the best means of preventing
Orchid diseases, and efforts should be made to keep the plants vigorous
and, therefore, capable of resisting attacks by insect pests.

Plants are also benefited greatly by having their position in the houses
changed, and that is one of the great advantages of the periodical
inspection, for during this process the relative positions of the plants
are altered.

It should be said that Cattleyas and other common Orchids badly affected
by disease had better be burnt, for it is cheaper to buy a healthy young
plant than to waste time in trying to bring the unsightly and diseased
specimens back to health.

The Cattleya Fly (_Isosoma orchidearum_), first imported probably with
_Cattleya Dowiana_, and frequently with other Cattleyas since, affects
the new growths, the grubs causing them to swell and rendering the
growth useless. The same species, or one closely allied, also attacks
the young roots of Cattleyas, Laelias, and their hybrids, causing
unsightly galls on the points of the roots. Fumigation, with some safe
preparation to destroy the fly, should be carried out, and every young
growth and root-point as soon as they are seen to be affected should be
cut off and burnt. By adopting these remedies it is possible to get rid
of the pest. In purchasing freshly imported plants, care should be taken
to reject those which show signs of having been affected by the fly.

Thrips, Red Spider, and Aphides occasionally appear in every collection,
and the remedy is fumigation and sponging with an insecticide, which
some growers prepare for themselves, either by pouring boiling water
over coarse tobacco tied up in a cloth and adding a little soft soap, or
by making an infusion of quassia chips. But excellent insecticides can
be purchased already prepared, which are guaranteed to be safe and
effective, and being of uniform strength, they may be used with
confidence if the instructions given with the preparations are observed
strictly.

Avoid using paraffin and emulsions of paraffin, for it is dangerous, not
only to the plants sponged with it, but to all the plants in the house,
for it affects the atmosphere.

SCALE INSECTS

These appear much less in collections now than formerly, bec