western-queensland-gardening-guide.pdf - South West NRM

mite wax scale
White wax scale (Grasmrdia destructor) also occurs and attacks a wide range of plants,
both cultivated and native. This is a soft scale, the adult being about 5 mm in
diameter, and is found mainly on mature wood. Living young are produced and these
settle on the current season's growth. Direct injury by the scale is less important than
contamination of the fruit by a sooty mould which proliferates on the escudates from
the scale.
Control
Both these scales may be controlled by using an oil spray in mid November and again
(if necessary) in late December. Do not apply during the heat of the day as the oil will
cause severe burning and may even kill the plant. A narrow range oil such as Caltex
Lovis or Ampol Octron may be better than white oil.
For red scale use 150 mL of oil in 10 L of water. For white wax scale use 90 mL of oil in
10 L water. Spray leaves, branches and trunks. Use early in the mo
afternoon. Spraying during the heat of the day when temperature over 320C can
age the trees. Do not spray when the trees are short of water. It is preferable to
gate a few days before spraying. An insecticide like carbaryl can be added to
reduce severe infestations.
Citrus aphid
Citrus aphids are soft, black or greenish-black, sap-sucking insects, about 3
tenth inch) in length, which are found on omg shoots and flowers. They cause
distortion of the leaves which become c d and scorched in appearance, and
dieback of the shoots occurs. Growth is retarded and hit set affected. A
characteristic feature of an aphid colony is a sticky fluid which is produced. This is
partly sap from darn plant tissues and partly a fluid secreted by the insects. The
fluid provides a me which is suitable for the growth of dark coloured moulds
which can cover much of the surface of affected shoots. The fluid also attracts ants
which are therefore found in association with aphid infections. Aphids should not
cause too many problems for home gardens.
Control
Lady birds will control aphids given half a chance. However, if growth is severely
infested, Pirimor at 2.5 g in 100 L applied to young growth is a biologically-safe control
method.
Citrus gall wasp
This is a very small, black wasp which lays its eggs in young twigs during the spring
, causing conspicuous swellings or galls to develop on the
merge from the eggs and feed within the gall tissue of the
in spring. Each cavity in
ae pupate for a brief period
ce of the gall. The wasps
appear in September and October an
after emergence, usually