Page 180 - Tài liệu cây cảnh Bonsai4me Bonsai Basics

active when temperatures reach 10°C in the Spring and can be picked off by

hand at night time (!) or killed by using proprietary slug bait in the form of
pellets or liquid solution.
Cuckoo spit is evident by globules of white froth on the surface of leaves and
stems. Inside the froth are larvae known as froghoppers, these feed on the sap of
plants in the same way as aphids do, causing dieback and distortion of growth.
Cuckoo spit can be removed by hand and by insecticide.
Vine weevils are probably the worst enemy of bonsai! Unlikely to be
actually seen on the plant, their presence can be determined by irregular notches
taken out around the edge and centre of leaves. Far more destructive to bonsai
are the larvae of vine weevil, which feed on the root system commonly causing
the eventual death to the plant. Adult vine weevil are 8-10mm in length, black
with white/yellow markings running the length of their bodies. Vine weevils are
unable to fly but are excellent climbers and can occasionally be seen on the
underside of infected plants. Adult vine weevils are easiest removed from
affected plants by shaking or brushing the foliage from which grazing adults will
be dislodged. Vine weevil grubs are approx. 10mm in length, white with a red

‘head’. They feed on the roots of plants over winter and by early Spring pupate
into adult vine weevils which are all female and can go on to lay up to 1,000
eggs over the course of the year. Vine weevil eggs are spherical, brown and less
than 1mm in diameter - they should not be confused with slow-release fertiliser
pellets used by nurseries which are larger in size. Larvae that hatch in the warm
summer months can become adults by autumn. The presence of larvae is most
frequently discovered when repotting in Spring or when trees suddenly die from
a lack of roots! Vine weevil grubs can only be dealt with at present by removal
by hand or by a small number of proprietary chemicals on the market. Most
effective is "Bio Provado Vine Weevil Killer" which is used as a soil drench
protecting the foliage against adult vine weevil attack for a month and vine
weevil larvae attack for 6 months.
Scale insects are sap sucking insects that attach themselves to the bark of

bonsai and cover themselves in a protective shell brown shell. These are best
removed by handpicking, as contact insecticides are unable to bypass the
protective covering.
Red spider mites are very tiny sap-sucking insects that attack trees
(especially coniferous plants) in hot, dry periods. The mites are hard to see with
the naked eye but their presence can be detected by fine webbing around the
foliage. Contact insecticides are effective against affected trees and regular
misting of foliage in hot, dry weather will deter infestation.
Fungus Gnat/Scarid Fly are tiny flies that can be seen flying around trees that