Page 95 - Tài liệu Ebook cây cảnh Bonsai Basics

HEA LTHY BONSA I 97

,.I
caterpillars. Sometimes they develop in !'
the leaf and flower buds. I :I
Caterpillars are not always easy to
eliminate, as they are sometimes resis- i'
··l
tant to insecticides. Remove them by
hand where you see them and destroy
them. An insecticide powder, which
stays on the leaves longer, can give good
results, as the caterpillars absorb it as
they eat their way through the leaves. It
I
•;
may be possible to catch some species in
a saucer of glue placed at the base of the ,,
I
tree. This will prevent moths from climb-
ing the tree at night in autumn and laying
their eggs on the leaves. Scale insect

Scale insects tiny, red spider mites are visible to the
Minuscule insects which cling firmly to naked eye because of their bright colour.
branches and trunk, protected by a scaly The tetranychus group are particularly
outer shell. These insects are destructive voracious. the adult mite piercing the
pests. The female penetrates the plant's backs of the leaves to suck out the sap.
skin and sucks out sap. Like aphids, they They most frequently attack conifers,
encourage the spread of fungal and viral the needles of which then turn yellow
diseases. Control with an oily insecticide and drop.
in winter, then scrape away any dead Mites are quite resistant to insecticides
bark. Eggs will continue to develop (which are formulated to kill insects, but
under the shells of dead insects. It is vital not necessarily mites). Special products
to burn all debris from the scraping. are hard to find. The most effective
Another method is to dip a small treatment is to prune away and burn
paintbrush or cotton bud in methylated infested branches.
spirit. This can then be painted on and
around the scale.
Ants
Ants are formidable pests in several
Insect larvae ways. Due to their fondness for aphids,
Some insects may lay eggs in the bonsai on whose excretions they feed, they can
compost, that is, in the root ball. The almost be said to 'farm' them, since they
larvae which hatch arc especially fond of convey them from one plant to another
young roots, which they devour, depriv- plant and protect them from predators
ing the plant of nourishment. So keep a such as ladybirds. In order to be near
watchful eye open during repotting, their food, ants also tend to congregate
when you can destroy larvae with your in nests in the soil around the roots,
fingers. You could also use a suitable causing havoc in the root system and
insecticide like HCH . cutting through roots as they carve out
tunnels. The sole remedy is to set a trap
for them on the surface of the root ball.
Red spider mites lfan ant's nest is set up in the root ball,
For long mistakenly thought of as in- the only solution is to lift the plant from
sects, red spiders are actually mites, its tray. Brush off the soil and eliminate
about which relatively little is known, as many larvae as possible. When dis-
due to their microscopic size. Though turbed, ants are easily dislodged.