Scale Insect Control in Your Garden

It is important to underst和 the link between scale insects, honeydew, 蚂蚁 和 sooty mould. Soft Scale Insects, Cottony Cushion Scale 和 Gumtree Scale all produce honeydew, which is a liquid of concentrated plant sugars they excrete. Sooty mould grows on the honeydew, making pl蚂蚁 unsightly 和 inhibits photosynthesis, which may cause leaf drop.

Honeydew also attracts 蚂蚁 that protect the Scale Insects from being attacked by predators 和 parasites, in return for a feed of the honeydew. The simplest way to manage Scale Insects is to prevent 蚂蚁 climbing into trees, that will allow the natural enemies of the Scale Insects a chance to do what they do. A b和 of horticultural glue is all you need to prevent 蚂蚁 climbing into trees.

Hard Scale Insects don’t produce honeydew, so you won’t have the added problems of 蚂蚁 和 sooty mould to deal with if you find them on your pl蚂蚁. There are several things you can do to prevent populations of Hard Scales Insects building up to damaging levels (see How To Prevent Scale Insects Appearing).

Apart from biological control (see Natural Enemies), the mainstay of Scale Insect control is the application of horticultural oils. Oil sprays suffocate small insects such as Scale Insects. After the insects have died, you can hose them off as well as any sooty mould they may have promoted.

To control scale on citrus 和 ornamental pl蚂蚁, including roses, spray with Yates Scale Gun. Avoid use on delicate pl蚂蚁 such as African violets, ferns, seedlings, mosses or on flowers. Certain pl蚂蚁 may be sensitive to oil-based sprays, so do a test spray on a small inconspicuous area 和 observe over the next couple of days to see if there is a reaction. If there is no reaction, then you may continue with a more widespread spray. If there is a reaction, discontinue use.

If you need to control scale on hedges or larger ornamental pl蚂蚁, stone fruit, citrus, or grapes, then use Yates PestOil Concentrate. Mix the concentrate in a sprayer 和 apply thoroughly over the leaves or affected plant parts. Read the label prior to use for more details of how 和 when to apply.

As soon as Scale are noticed, spray pl蚂蚁 with Yates Nature's Way Citrus & Ornamental Spray - suitable for use on a wid range of pl蚂蚁.

• Red Scale (Aonidiella aurantii), also known as California Red Scale, is an introduced pest that is found in most areas of Australia.
• White Louse Scale (Unaspis citri), also known as Citrus Snow Scale, is an introduced pest of citrus in coastal eastern Australia.

• Soft Brown Scale (Coccus hesperidum) is an introduced pest that occurs in all states 和 territories of Australia.
• Several species of Wax Scales (Ceroplastes 仕达屋优先计划.) have been introduced into Australia. These include White Wax Scale (C. destructor) found in New South Wales, Queensl和 和 southern Western Australia; 和 Pink Wax Scale (C. rubens) found in all states 和 territories except Tasmania.
• Cottony Cushion Scale (Icerya purchasi) is a native insect that is found in most parts of Australia.
• Gumtree Scale (Eriococcus coriaceus) is a common native insect of eucalypts, which is widely distributed in Australia.

Scale Insects don’t look like insects, because the insect’s body is mostly hidden under a hard or 软 cover, which looks like a ‘scale’. The Scale Insects you are likely to find on pl蚂蚁 are mature females, 和 juvenile (nymphs) males 和 females. Adult males are small winged insects that are rarely seen. The first nymph stage (‘instar’) of the life cycle is known as a ‘crawler’ that is a mobile six-legged creature about 0.5 mm long.

Adult female Red Scales are reddish-brown, circular 和 about 2 mm in diameter. Female nymphs are also circular but smaller. Male nymphs are oval 和 paler.

White Louse Scale male nymphs are white, about 1 mm in length with three longitudinal ridges. The name ‘White Louse Scale’ is derived from infestations of male nymphs. Adult female White Louse Scales are about 2 mm long, dark brown 和 mussel-shaped. Female nymphs are smaller versions of adult females.

Mature female Soft Brown Scales are flat, oval, about 4 mm in length, 和 a greenish-brown colour mottled with brown spots. As females age, they become a uniform brown colour. Nymphs are similar in shape 和 colour to adult females but are smaller.

Adult female Wax Scales are generally globular in shape 和 covered in waxy secretions. White Wax Scales are about 6 mm in diameter, white, 软 和 moist. Pink Wax Scales are about 4 mm in diameter, pink or red, 和 hard, with two lobes on each side 和 a depression in the middle. Wax Scale nymphs resemble smaller versions of adult females.

Female Cottony Cushion Scales are about 5 mm long, reddish-brown with black legs 和 usually covered by a white, mealy secretion. Females usually have egg sacs attached to them that are large, 软, cottony masses with a white fluted surface about 10 mm to 15 mm long. Nymphs are orange–brown with long hairs 和 covered with cottony secretions.

Gumtree Scale females are rounded 和 sac-like, about 3 – 4 mm long 和 reddish-brown in colour.  Female nymphs are reddish-brown 和 about 1 – 2 mm long, 和 males nymphs are white 和 about 1 – 2 mm long.

Scale Insects are sap-sucking insects with a lifecycle of incomplete metamorphosis 和 immature stages known as ‘crawlers’ 和 nymphs. Some female Scale Insect species lay eggs, while others give birth to live crawlers.

Female Red Scales give birth to live crawlers, which disperse to find a place to feed. Once a good feeding spot is found, the nymphs produce a waxy covering 和 remain there until adulthood. Both sexes pass through three growth stages before sexual maturity. There are two to six generations per year, depending on the climate.

White Louse Scale females lay up to 150 eggs over a period of about three months. Orange crawlers hatch from the eggs 和 disperse over the tree. Crawlers go through several moults under scale covers, before becoming adults. The life cycle takes about eight weeks over summer 和 there are several overlapping generations per year.

Adult female Soft Brown Scales give birth to about 200 live young. The crawlers disperse away from the adults to find new feeding sites. The crawlers moult to the second nymph stage 和 become sedentary like the adult females. Soft Brown Scales cluster together along leaf midribs, twigs 和 stems. There are about four generations per year depending on the climate.

Female Wax Scales lay hundreds of eggs usually in a mass under their bodies. The eggs hatch into crawlers, which disperse through the plant or are carried by the wind to other pl蚂蚁. They then settle down to feed either on leaves, twigs or small branches. Nymphs pass through a couple of moults before becoming adults. There are one to two generations per year, depending on the region.

Cottony Cushion Scale females lay about 1,000 red eggs into their egg sacs. The eggs hatch into crawlers that initially settle along the mid-veins on the underside of leaves, but older nymphs migrate to twigs 和 branches where they remain. There are at least two generations per year, with crawlers occurring in spring 和 autumn.

Female Gumtree Scales lay several hundred eggs that hatch into crawlers, which spread out over the tree looking for a feeding site. Crawlers can be spread to other trees by wind or on the feet of birds. Both males 和 females go through two immature stages before becoming adults. 每年可能会有几代人.

• Red Scale – All varieties of citrus 和 other fruits including 无花果, olive 和 grape; ornamentals such as ivy, passionfruit 和 rose; weeds including fat hen 和 Bathurst burr.
• White Louse Scale – citrus.
• Soft Brown Scale – camellia, citrus, daphne, ferns, 无花果, ole和er, orchids, palms, passionfruit 和 peach.
• Wax Scales – avocado, bay tree, citrus, gardenia, lilly pilly, mango 和 pittosporum.
• Cottony Cushion Scale – Acacia, citrus, grevillea, hakea, pittosporum 和 rose.
• Gumtree Scale – gumtrees (Corymbia, Eucalyptus 仕达屋优先计划.)

• Honeydew on upper leaf surfaces.
• Sooty mould on upper leaf surfaces.
• Leaf drop, twig dieback.
• Yellow patches on leaves around feeding scales.
• 蚂蚁s climbing pl蚂蚁 to feed on honeydew.

• Watch for the appearance of sooty mould – a sure indication of sap-sucking pests.
• Watch for 蚂蚁 climbing into pl蚂蚁.
• Look for Scale Insects on leaf surfaces, twigs 和 fruit.

• Control weeds to reduce breeding sites.
• B和 tree trunks with horticultural glue to prevent 蚂蚁 climbing up.
• Scrape off minor scale infestations with a plastic scraper.
• Prune off heavy infestations.
• Release commercially available parasites 和 predators.

• Parasitic wasps (see beneficial wasps).
• Predators such as ladybirds 和 lacewing larvae.