The damage often seen on our plants can be due to many causes, one of which, may be insects.
To recognise the damage caused by a few of these pests will enable the gardener to take the appropriate action, if necessary.
Summer is the breeding season for scales, the sucking insects that come in a range of shapes and colours.
At this time of year baby scales emerge and start looking for a good place to feed.
If numbers are small remove with a small brush or spray with a proprietary white oil.
The leaf webber is the caterpillar of a native moth that prefers close-leaved plants like leptospermums and melaleucas.
As it feeds the caterpillar binds the leaves together with a thick mat of its excreta to form what looks like a spider's web. Carbaryl is usually an effective control measure.
The woolly aphid is mostly a pest of apple and ornamental crab apples where it encrusts the twigs and branches with woolly galls.
These aphids exude honeydew which attracts ants and sooty mould. A systemic insecticide is recommended.
Lerps or psyllids are native insects that suck the sap from leaves of eucalypt, acacia, angophora, ficus and syzgium trees.
There are many species, each causing different signs of damage on the infested plants.
The species that causes the characteristic brown, yellow and red striping to the leaves lives on the underside of the leaves under a hard covering.
Established trees can usually out grow any damage as natural predators such as birds, spiders and ladybirds tend to keep the populations under control.
The leaf blister sawfly is often found on the leaves of eucalyptus where they feed on the tissue between the upper and lower surface of the leaf.
Leaf-eating insects on mature trees rarely cause sufficient damage to require control but if necessary spray with a systemic insecticide. Pests on young trees can be removed with a gloved hand.
There are many types of thrips that rob sap from plants causing a range of destruction from bleaching the leaf colour to flower failure and distortions of plant parts.
This insect curls up the growing tips of the leaves to form a protected feeding site.
Control consists of a thorough spray of a suitable insecticide.
There are a number of insects that cause galls on native plants with the most common being wasps and flies.
The adult insect lays its eggs into the plant's tissue and the chemical associated with the eggs causes plant cells to change character and form galls.
On hatching, the young insect larvae feed inside the galls.
These unsightly galls can be pruned from the tree if necessary.
White fly is hard to control but at least you can make their lifestyle uncomfortable by spraying with pyrethrum-based products.
Small populations can be ignored, especially on ornamental annual plants because they will usually be ready to pull out before the white fly can cause any major damage.
The most effective way to keep insect pest populations under control is to use basic common sense, that is practice horticultural hygiene, remove weeds as they appear, keep surroundings free of debris to eliminate hiding and overwintering places and encourage birds and beneficial insects with a selection of nectar-producing plants.
When applying insecticides always carefully follow the manufacturer's recommendations for safe and effective use.
Diary
January 2, 3: North-West Tasmanian Lilium Society Show at the Burnie Arts & Function Centre. Saturday 8am-4pm, Sunday 10am-4pm.
January 23, 24: Latrobe Lilium Show at the Latrobe Memorial Hall. Saturday 8am-4pm, Sunday 10am-4pm.
